Late-model Mexican Beetles and The ACD Air
Contents
1. cet TE BE 0 VAG COM Protocol KW1281 Open Controller m Controller Info VAG Number 043 906 022 E Component DIGIFANT 1 82 3684 Soft Coding Shop Extra Extra This information will vary slightly depending on the year vehicle This is from a 2001 model year The 2000 models used the 043 906 022 D version which is nearly identical in function The earlier years 16 may go back to 043 906 022 B that is Digifant 1 80 apparently with fewer features supported for diagnostics Fault Codes These Digifant versions do support DTC storage or Diagnostic Trouble Codes like OBDII cars When the controller or ECU notices a sensor reading outside the range it expects it will log an error code that identifies the problem With VAG COM you just click on the Fault Codes button and it displays all the stored DTCs Here is an example caused by a loose O2 sensor cable VAG COM Fault Codes r Controller Info VAG Number 043 906 022 E Component DIGIFANT 1 82 3684 Fault Codes 1 DTC s Found 00525 Oxygen Sensor G39 03 10 No Signal Intermittent Print Codes Copy Codes Clear Codes 05 In this case VAG COM shows both the basic code 00525 and the additional information code 03 10 that it is an intermittent fault After recording the codes click Copy Codes and paste to a Word document you can erase the codes b2. This is not intended to be training in engine management systems and diagnostics for an owner of the older carbureted cars The procedures used are similar to those for modern VW models using computerized engine management systems and this is intended to be an aid for technicians already familiar with the general procedures so they can apply their expertise to the air cooled engines Mechanics unfamiliar with these systems and procedures can gain understanding from readily available sources such as the Scan Tool Companion and other publications from Bentley Publishers The Bentley website technical forums www bentleypublishers com are also an excellent resource Introduction Those of us who drove early 60 s Beetles when they were new have always felt connected to them and as we have lived with the more complex and comfortable modern cars have longed for the simple transportation of the Beetle Eventually many of us bought and restored old Beetles and found that 35 year old carburetors and ignition systems aren t as reliable as we remembered We also may feel guilty about the relatively dirty exhaust of the old cars although with so few on the road this is more of a symbolic issue than a problem Wouldn t it be nice to have a new old Beetle with a solid clean running engine without fussy carburetors and distributors Along came Btlmex and others who could take your old U S registered Beetle and put on a b
3. but it is not drilled or tapped for the mounting stud This can be easily done by removing the lower tinwork and heat exchanger on the right side to gain access The mounting point for the linkage return spring is different than the older doghouse shroud so the older spring would stretch too far and put too much tension on the mechanism Either get the later Brazilian spring or add an extension wire to the spring Adding the shutters will increase the defrost air flow when the engine is cold as they reduce air flow to the engine raising the shroud internal air pressure causing more flow to the open heat exchanger path Once the shutters open as the engine warms the defrost flow is the same as without shutters but the warmer air is effective The shutters may actually cause the oil to warm up slower than without them With the doghouse shroud the shutters do not close off airflow to the oil cooler So the higher shroud pressure with the flaps closed results in more cold air flow through the oil cooler It is probably best for he engine to leave the heater controls for the passenger compartment fully on during engine warm up In the 70s VW sold accessory covers to block some of the engine compartment inlet vents in cold weather as the doghouse design does over cool the oil in these conditions This is obvious if either an oil temperature gauge or oil pressure gauge is added Synthetic oils Ow30 OwW40 or 5w30 5w40 should flow and lubricate
4. better in these conditions but the colder oil temperatures may still result in water condensation accumulating in the oil More frequent oil changes are still a good idea in cold weather 10 Ignition System There are several changes to the ignition system in these models 1 A breakerless non advance distributor is used similar to the one used on the 86 91 wasserboxer in the Vanagon 2 Advance is controlled by the Digifant ECU 3 The signal from the ECU triggers a square coil with an integral electronic module Also used on Golf Jetta in the 1990s 4 The plug wires uses the newer style electrical connector that grip a pin in the distributor cap rather than expand into a ring in the cap The older wires will not work properly unless an older style cap is also used 5 The spark plugs are now 34 inch reach longer threads due to the thicker head walls This should reduce cracking of the heads around the spark plug and valve seats These changes mean that timing should not change due to normal wear a stronger spark is produced and less maintenance is required Transmission The transmission uses the swing axle design of 1968 with the wider brake shoes 4 bolt drums and long spline axles introduced that year It also uses the Z bar for suspension control Although this sounds strange to the US enthusiast where the swing axle disappeared after 1968 this style never actually went out of production for the rest of
5. left 043 906 022 E b Center mounted throttle body 1BO 133 061 Throttle position sensor G88 044 907 385 A Intake air temperature G42 1HM 906 501 a e Dual tube intake manifold without pre heat pipes as fuel injectors are at the heads BAA 129 711 BAA 129 705 BAA 129 706 and 2ea BAA 129 729 A f Port fuel injectors N30 33 BAA 906 031 g Manifold pressure sensor in the J169 ECU under the seat with vacuum line to manifold h Hall sender G40 in distributor Distributor 043 905 205 N i Engine Temperature Sender G27 in head at cylinder 4 113 906 161 j Idle speed control valve N71 controls air around throttle body 048 133 455 k EVAP system vent valve N80 from charcoal canister 034 133 517 Fuel pump relay J17 m High pressure fuel pump mounted to frame head 043 919 051 n 4 wire Lambda OXS sensor G39 at inlet to CAT converter 043 906 265 B o Combined CAT and muffler which fit standard heater boxers Part Number 043 253 702 C 8 An electronic immobilizer is included on most cars that disconnects the ECU and starter if the correct electronic key is not present Some models use a key fob that must be inserted momentarily into a slot on the dash before starting the car while others use an RF wand that is sensed without direct contact Unlike modern US models this is not built into the actual key so keys can be duplicated This is NOT built into the Digifant contr
6. stock engine can use under any condition A pressure regulator at the engine bypasses the excess fuel back to the fuel pump holding a constant pressure above manifold on the system This assures that quantity of fuel injected is proportional to the duration of the injection pulse and doesn t have to also compensate for varying fuel and manifold pressure The recirculation of excess fuel is different from other models Most systems including the FI Beetles of 1975 1980 send the excess fuel directly back to the fuel tank through a second fuel tap in the tank The ACD system was designed so the familiar single tap fuel tank could be used This is done by using a special fuel pump design so access to a spare fuel pump is a good idea if you plan to keep your car many years However the pump appears to be very reliable so this may be overly cautious The pump is large compared to most cars and is mounted on the right frame head under the tank It has 4 hose connections an inlet from the tank an outlet to the engine a return line from the engine and a vent line to the vapor venting system that feeds back into the tank fill connection The pump location under the tank and vent system makes this single outlet fuel tank concept work well This also means that two fuel lines are run through the frame tunnel to the engine The Mexican chassis uses two 7mm steel lines Retrofitted chasses may either use two new metal lines or use the origin
7. the engine harness 5 A wire from the engine harness goes through the front tin to the starter Disconnect this at the starter when removing the engine Hydraulic Lifters The hydraulic lifters are a proven design having been used on the T4 engines and Wasserboxers since 1978 They are necessary for the ACD engine as variations in valve clearance affect emissions and can cause damage to the catalytic converter The hydraulic lifters keep optimum clearance with no user maintenance The lifters require greater oil flow and cleaner oil and thus also require the spin on filter pump with larger gears than used on older engines The full flow filter keeps the oil clean to prevent fouling the lifters and the larger gears provide more oil flow When properly bled and adjusted during assembly the lifters should not require re adjustment until an engine re build is needed Some owners report various problems with hydraulic lifters that can usually be traced to a couple of causes When adjusting the lifters the clearance is first adjusted to zero clearance and then an additional turn in to compress the piston in the lifter to allow them to self adjust This assumes that the zero clearance is when the valve train first contacts and the lifter piston is fully solid at maximum extension If the lifter has bled down and the zero clearance position is started with the lifter mechanism partly compressed an additional turn may bott
8. the world The IRS rear suspension however did go out of production once the US stopped importing the Beetle The transmission uses the familiar 12 volt starter and smaller bushing and unlike older swing axle transmissions adds the throw out bearing guide tube around the input shaft common to 1971 and later Beetles This means the later style throw out bearing must be used for replacements Brakes A dual circuit master cylinder is used with front disk brakes of the same design used on US KG cars Other worlds areas used these brakes on Beetles in the 70s also although they were not used on US Beetles This results in excellent brake feel and control but with the light Beetle front end it is still easy to lock the front brakes first and lose steering control The front disks do not require periodic adjustment but the rear drums do require adjustment just like the older Beetles The brake warning light is now an LED integrated into the gas gauge Wheels and Tires Because of the swing axle rear camber changes the Mexican production kept using 155R15 tires throughout Beetle production up until the Ultima Edicion special model that used a 165R15 whitewall tire Many people think the narrower 155 tire wears better with the swing axle transmission Both 11 General and Continental made tires in this for the Mexican market but they are very hard to find in the US The 165R15 tire may be the only feasible replacement There wer
9. Late model Mexican Beetles and The ACD Air Cooled Engine Disclaimers etc This is NOT an official service manual and the information and procedures contained herein have been gathered from various unofficial sources Technical information for the modern Mexican fuel injected air cooled engine has been nearly impossible to find leaving those of us who do not live in Mexico without the resources to properly maintain and repair our vehicles Fortunately the engines are extremely reliable and require less adjustment than the classic cars of the 60s and 70s I ve driven mine daily for 3 years and it has needed only oil and filter changes But when something does go wrong Having accumulated the various specifications and some procedures and by experimenting where procedures were not described I ve put this data together to help me maintain my cars Due to many requests I ve decided to make this available to aid other owners as well However not all information may be accurate and I assume no liability either for the correctness of the information or any damage or harm that may result from using the information and procedures contained herein Besides with my few resources and no insurance a lawsuit wouldn t be worth your time anyway The author has no association with any Volkswagen company and use of trademarked terms are purely for identification and in no way imply any connection or endorsement of a Volkswagen legal entity
10. There is a way to bypass the immobilizer so the key fob is not needed but that will not be covered here for security reasons The Ultima Edicion and other 2004 cars used an RF wand that did not need the socket on the dash Windshield Washer A new electric pump washer tank is used that mounts to the left front quarter panel inside the trunk and is formed to fit the Beetle side with minimal effect on the trunk It mounts to one of the fender bolts which is longer to allow a nut to hold the bottle in place 13 Electrical System The familiar Bosch 51Amp alternator with internal voltage regulator is used on the engine The standard battery supplied is a 36AH unit much lower capacity than the 45 AH battery used in the 70s The new systems put a small continuous drain on the battery and many users report their cars will not start if unused for several weeks Adding a modern radio also adds to the current draw as most radios now include clock and active electronics that consume some power even when shut off A standard group size 42 battery with higher capacity is a good replacement Headlights are now halogen with separate bulb Front turn signals are mounted in the front bumper Replacement Hella units from several US suppliers fit correctly Bumpers The bumpers look like those on the 68 73 cars except the black stripe along the middle of the bumper is wider and the front bumper has cut outs for the turn signals However differe
11. a ul 812 3 57 ms 13 31 20 C Engine Speed Inj Period Supply Voltage Intake Air Temp 760 890 rpm 2 5 3 5 ms 12 15 V 20 100 C Group Idle Functions oo ee a 812 56 0 3 57 ms Engine Speed N71 Current Inj Period 760 890 rpm 19 60 Dec 2 5 3 5 mM 0 19 YAG COM Measuring Blocks Basic Settings Sample Rate or gt VA G COM Reading Header Label File 043 906 022 LBL Measuring Blocks Group Basic Load Idle a 812 35 5 255 0 01000000 Engine Speed Eng Load 2 2 2 2 2 s ween nn 760 890 rpm 22 35 255 00000000 Group Vent Functions Idle 005 ea ua 812 0 0 217 0 Engine Speed N80 Current Atm Pressure 760 890 rpm 0 0 174 250 Group Idle Functions a Ba 36 0 130 0 53 0 72 0 Engine load Lambda Learn N71 Current Throttle 60 100 Dec 80 140 Dec 19 60 Dec 11 103 Dec Sample Rate 1 7 VA G COM Label File 043 906 022 LBL Measuring Blocks Group Idle Functions a Te a cy LDn J Engine Speed wren anne nnn N71 Current 760 890 rpm 0 0 16 80 Dec The default VAG COM labels for the readings are generally good but a custom label file 043 906 022 lbl used in the above screens gives more detail Measuring Block table 20 The specified data is in the following table Note that specified ranges are all when recorded with the engine idling after full warmup Zone 1 Zone 2 Zone 3 Zone 4 Engine Speed idle 760 890 Engine Temperature 80 120 C O2 signa
12. a problem especially in the USA I understand VWoA doesn t special order parts that are not used on US models but the VW dealers in other world areas may be able to do so Some of the parts are also used on other VW cars of the 90s and are available from US dealers Some are unique to this model and you may need to go to a Mexican dealer to get them If you plan to keep your car a long time you may want to get and keep spares of key parts www btlmex com does list some parts and may be able to get others but there is no guarantee how long the parts business will be viable for them to continue I hope you find the following information useful Tom Brunson Aging VW owner and enthusiast General Information The air cooled Sedan model produced by Volkswagen Mexico in the 1993 2003 years used the classic 1600 engine with some updated components It is known as the ACD code engine Differences from the engines in older models include 1 Hydraulic valve lifters similar to the type 4 and waterboxer lifters are used so valves stay in adjustment and should not be adjusted between rebuilds 2 Revised cylinder heads that take a 34 reach sparkplug 3 A full flow filter pump is used with larger 30mm gears for higher oil flow This provides better filtering to avoid fouling the hydraulic lifters Because of the higher oil flow pressure is better maintained in hot climates Factory spec oil is 15w40 for the Mexican climate ra
13. al 5mm fuel line and a new line The capacity of the original 5mm line is of course less than the 7mm lines expected by the ACD design but many of the converted cars use it without obvious problems Many conversions use copper tubing for the new fuel lines often running through plastic tubing to prevent rattles If copper tubing is used check to see that it is well secured and supported as copper work hardens from vibration and can eventually fail from fatigue The line supplying fuel from the pump to the engine exits to a hose going to a can type fuel filter mounted to the bottom of the rear parcel shelf above the rear torsion bar This should be a long lasting part but is also a good candidate to keep spares Factory recommendation is 60 000 km replacement From the filter another hose runs to the fuel loop of the engine going to the injector rails then to the pressure regulator and back to the return line going up the tunnel to the pump The fuel injectors are located at the manifolds on the cylinder heads and inject directly at the intake ports This vaporizes the fuel at the heads which helps cool the heads and prevents fuel condensation in the intake manifold so no manifold heating is necessary Fuel injectors can clog from very small amounts of foreign material so anytime it is necessary to open the supply lines beyond the fuel filter the area should be well cleaned prior to opening the lines and extreme care taken to keep dir
14. ch running during warm up is minimized by the Digifant system On older engines with carburetor and choke the mixture would be very rich with a cold engine and fuel would condense on the cylinder walls washing off the oil film causing rapid wear The Digifant is less rich on startup and leans out rapidly to prevent this cause of wear 2 Classic engine oils were so thick when cold that they could not flow through the oil passages well and much would bypass directly to the sump giving less flow to the wearing parts Modern oil such as 0w40 synthetic flows so well at cold temperatures that oil pressure should stay low enough to keep the bypass relief closed providing better flow to the wearing parts 3 Modern synthetics also have better lubricating properties when cold also causing less wear While the Mexican domestic climate may not see the extremes of other world areas these system considerations probably had more influence on the decision to drop the thermostat than the climate Because these cars use the basic heat and ventilation system with defrost vents only in the corners of the windshield defrost in the mornings in cold climates can be a challenge It can be improved by fitting the thermostat and shutters used on the 70 s engines The fan shroud and engine tin still has the mounting points and the shutters and linkage can be easily fitted The engine case still has the cast boss where the thermostat bracket would be mounted
15. e some factory accessory aluminum wheels styled similar to the New Beetle wheels available in Mexico However nearly all production used the familiar steel wheel Most models came with a small center plastic cap for the axle end and with plastic caps over the lug bolts However the wheel is made to fit the common steel hub caps used in earlier years Chassis The original chassis on these cars resembled a 1975 Fuel Injected Beetle chassis with the later style floor pans and seat mounts and dual fuel lines The front transmission mount was the pre 73 style Because of the swing axle rear suspension no inner pivot brackets were used However the frame horns were formed to fit them with blanking plates welded in Of course nearly all cars imported to the US were re mounted on a 1973 or earlier chassis modified as needed to fit the later parts Thus a 69 or later chassis could easily be fitted with a later IRS suspension if desired Most of the older chassis will have had new floor pans welded in to fit the new style seats new fuel lines run to the rear and possibly repair to the clutch tube through the chassis etc www btlmex com was selling the Mexican chassis removed from their conversion cars and while these would likely not be legally usable for US registration they could be a good source for chassis repair parts The possible use as a chassis for replacement use would depend on the codes of the state having jurisdiction Instrumen
16. ease air to the defrost vents There is no fresh air ventilation system Anti theft devices Both an alarm system and electronic immobilizer were standard for the last years of Beetle production The alarm uses a mechanical key switch in the left front quarter panel using a round key It senses the door light switches and similar switches mounted on the front hood and rear engine hatch Opening any of them will cause a separate horn to sound which is mounted in the engine compartment The immobilizer is a small relay box that switches power from the starter and ECU if an attempt is made to start the car without keying the immobilizer Most cars used a key fob chip that had to be inserted into a socket in the center of the dash and then removed The car could then be started within 30 seconds An LED on the socket would flash when the immobilizer would was not reset to start the car There have been cases where the both relays in the immobilizer did not latch correctly allowing the starter to work but not the ECU so the car would not run Usually keying the circuit again would correct this Replacement keys to match the immobilizer are not available but a complete replacement unit with 2 keys is available from btlmex com The immobilizer box itself is mounted in an inaccessible area Most were under the rear seat by the ECU protected by a heavy metal shield attached by shear bolts to prevent tampering
17. ech information does not give a step by step procedure but notes that the vacuum signal line from the manifold to the ECU should be disconnected when checking setting timing The specified setting tolerance is 5 7 degrees BTDC at 1500 rpm with a fully warm engine however the method for obtaining the conditions to set the timing this way were not specified in the information I have found In normal operation the Digifant system controls advance dynamically Timing cannot be adjusted in the normal Basic Setting mode as it controls the engine speed down to 830 It is possible that the timing could be set by carefully holding the RPMs at 1500 in normal mode but this is touchy If anyone has further information about out to obtain the setting conditions please let me know Some VW ECU systems that require a timing adjustment like the MP9 0 system also not sold in the US will control the engine to the correct conditions when Basic Setting is initiated with a certain measuring block displayed but I have not yet discovered such a function in this Digifant system With lack of the correct procedures to get the timing at 1500 it appears close timing could be obtained by setting the timing mark TDC at the case split at normal idle and check at 6 BTDC as basic setting mode is started At the least it would be a good idea to check the setting on a car and record the results so it could be duplicated if a distributor needs to be replaced 23 Other O
18. eed Stabilization Valve Wiring or defective part N71 short or open circuit Fuel Pump relay J17 short to Wiring positive Control Unit Defective Replace ECU J169 Measuring Blocks Besides simply reading and clearing DTCs the VAG COM software lets you watch engine and sensor readings while the engine is running using the Measuring Block functions like the VAG1I552 This can be very useful for troubleshooting to compare actual readings to the expected range of values Also by recording the readings while your engine is running properly you have a starting point to look for changes when trouble occurs It is a good idea to take snapshots of the measuring block values on your properly running engine for comparison later VAG COM lets you display more than one block at a time but as you display more than one measuring group the sample rate decreases You get fastest readings by displaying a single block 18 VAG COM Measuring Blocks Basic Settings Sample Rate 1 3 7 VA G COM Label File 043 906 022 LBL Measuring Blocks Group Group a a S Group or E e O o VAG COM Measuring Blocks Basic Settings Sample Rate 01 5 VAG COM Reading Header Label File 043 906 022 LBL Measuring Blocks Group Basic Functions Idle H al 83 C 0 79V 00000000 Engine Speed Engine Temp Lambda Signal Binary flags 760 890 rpm 80 120 C 0 0 1 0 Y 00000000 Group Basic Functions Idle ca E
19. et the digital values in field 4 of measuring block 1 will all read 0 VAG COM Measuring Blocks Basic Settings VAG COM Measuring Blocks Sample Rate 01 S Reading Header Label File 043 906 022 LBL Group Basic Functions Idle U i 001 Gi 840 83 C 079V 00000000 n Engine Speed Engine Temp Lambda Signal Binary flags 760 890 rpm 80 120 C 0 0 1 0 Y 00000000 21 Once these conditions are met display measuring block 000 which is where Basic Setting should be initiated VAG COM Measuring Blocks Basic Settings Sample Rate 1 2 VAG COM Label File 043 906 022 LBL Basic Settings Group 000 ae 052 140 0o05 Joss 124 ooo ooo 072 007 207 Dr 1 2 3 4 5 6 F 8 g 10 The display zones relate to Zone Variable 1 Intake Air Temperature 2 Battery Voltage 3 Engine Temperature 4 Load vacuum sensor 5 Lambda probe signal 6 Vacant 7 Vacant 8 Throttle Valve Potentiometer 9 Injection Period 10 Engine Speed The values are not in engineering units but are simply the digital values read on each channel Before entering Basic Settings these values should be seen Display zone 3 Engine Temperature below 044 Display zone 8 Throttle Valve Position above 008 and less than 113 Display zone 10 engine Speed above 128 If so click on Switch to Basic Settings If the timing checks OK see Ignition Timing below wait for at least 60 seconds in basic settings mode
20. for all climate conditions Owners also notice lifter clatter occurs more often if the engine is started and stopped without being allowed to warm up Wasserboxer owners also report this Avoid this when possible People familiar with exhaust valve stretching and failure on older VW engines may be concerned that this condition will not be detected with hydraulic lifters However the operation of the ACD as a system makes valve problems less likely than on older engines Exhaust valves are largely cooled by heat transfer to the valve seat when closed Hydraulic lifters maintain consistent valve operation assuring the valves are in contact with the seats the proper cycle time to provide cooling The Digifant closed loop system keeps proper mixture to avoid overheating from a lean condition Finally the port injection helps cool the heads through fuel vaporization Added up the likelihood of valve problems is greatly reduced and should not be a concern Engine Cooling and Warm up Older VW engines were known to wear faster if thermostats and shutters were removed The ACD engine does not come with either installed and owners may be concerned about the effect on engine life Although the decision not to use this system on the ACD certainly included cost concerns there also may be less need for them and the effect on engine life should be minimal Rapid engine wear during warm up has several causes which are minimized for the ACD today 1 Ri
21. for the system to learn and save the adaptation figures Values include Ignition timing 5 7 deg btdc 1500 Idle speed 800 860 rpm CO content pre CAT 5 5 8 5 Lambda signal zone 5 100 250 fluctuating Load manifold pressure zone 4 50 100 HC value lt 300 1000 After at least 60 seconds has elapsed the ECU learns and stores the settings Then exit Basic Settings mode and check the fault memory to assure no faults were reported 22 Ignition Timing Ignition timing is checked by aligning the TDC crankshaft pulley mark with the engine case split line using a digital advance timing light to measure the advance Unlike older Beetles there is no mark on the pulley at the correct advance although one could be added at 6 degrees BTDC In normal operation the Digifant ECU controls the ignition timing so an attempt to check timing at normal idle will not give the expected result In fact the retard at normal idle is to approximately 0 TDC This means a rough check with a timing light will show the TDC mark about at the case split This is not a very accurate check but can be an easy start to look for problems When you initiate Basic Setting mode the Digifant ignition control is disabled and the idle is controlled to 830 rpm so the timing can then be checked by a digital advance timing light to see if the TDC pulley mark lines up with the case split The checking tolerance is 4 8 degrees BTDC at 830 30 rpm The available t
22. ght must be used for the setting or a degree pulley may be temporarily installed In normal operation the ECU adjusts timing so this must be disabled by using the VAG1552 or VAG COM to check or adjust timing Ignition timing does not normally change with age and wear and should not require periodic adjustment 2 A Basic Setting procedure which matches the ECU to the throttle body and engine sensors storing the adaptation value in non volatile memory so it is not lost if the battery is disconnected This procedure is covered in detail in a following section Because of the spin on oil filter recommended oil change intervals are extended compared to earlier Beetles up to 7500 km 4600 miles as on other VW car models Engine Specifications Power rating 34 KW 44 hp at 4000 rpm Max torque 98 1 Nm 132 ft lb at 2200 rpm Displacement 1584 cc Bore 85 5 mm Stroke 69 mm Compression 7 75 1 Fuel Required 87 AKI regular unleaded Rated fuel mileage 13 9 km l 32 5 US mpg Max cruising speed 127 kph 78 mph Spark Plugs NGK BP5ES A 3 4 thread length Champion N12Y VW part 101 000 047 AA set of 4 Plug electrode gap 0 7 mm 0 028 Engine Oil Capacity 3 0 liters 3 2 US qt with filter change Fuel Supply System Overview The ACD engine requires fuel pressure at the injectors to maintain a constant pressure above the manifold pressure The fuel pump delivers a near constant volume of fuel which is more than the
23. l in Volts 0 0 1 0V Digital Code 8 bit all 0 for Basic Setting Engine Speed idle 760 890 Injection period 2 5 3 5ms at idle Supply Voltage 12 0 15 0V Intake air temperature 20 100 C default Functions Engine Speed idle 760 890 Current to idle control valve 19 60 at idle Injection period 2 5 3 5ms at idle Engine Speed idle 760 890 Engine Load 22 0 35 at idle 00000000 default Functions Engine Speed idle 760 890 Current to N80 evap valve 0 at idle Ambient Pressure digital 250 sea level 6 Basic Engine Load decimal 50 100 O2 learning value decimal 80 140 Current to idle control valve Throttle Position default Functions digital 11 103 at idle 19 60 at idle Engine Speed idle 760 890 Current to idle control default valve 19 60 at idle Functions Performing Basic Setting The ECU is matched adapted to the throttle body and engine sensors by using VAG COM to initiate the Basic Setting mode This procedure is only valid providing all engine sensors are operating properly and the following conditions are met Ignition timing checks 6 deg 1 deg Engine running at idle speed throttle fully closed under 2150 rpm Engine at normal operating temperature more than 80 deg C No DTCs fault codes stored in ECU memory All electrical consuming accessories turned off ei When these conditions are m
24. made as some have the connector on a removable cable Ross tech ISO COM However many build the interface electronics into the connector Use the shell and contacts listed below Most would probable prefer making an adapter cable to leave both the car and the interface un altered This requires a 3 pin connector shell 357 972 763 two double ended contact pigtails 000 979 129 15 to get three contacts plus a spare a 16 pin DLC connector shell 1HO 972 695 and two double ended contact pigtails 000 979 131 for it Wire this per this pin out Car Connector OBDII 16 pin connector Pin 1 Striped K line pin 7 Pin 2 Brown Ground pin 4 Pin 3 Red 12V pin 16 Cut off the mounting ears from the DLC shell for dash mounting and shrink 2 layers of 1 2 heat shrink tubing over the back as shown to serve as a handle General Procedures VAG COM can be run on a small tablet PC which makes a very portable and handy diagnostics system 00 aaahh a 022000000 amp Eh D ea After connecting the cable and starting the laptop and VAG COM software turn on the ignition and select the Engine Controller VAG COM also supports a lot of other controllers used on other VW Audi vehicles but only the Engine Controller is used on the Sedan The laptop attempts to communicate with the car and after a minute of trying different protocols it will display the following controller info ej VAG COM Open Controller
25. nge but in a wider temperature climate a 5w40 or OW40 synthetic is more appropriate The 70s dual relief oil pressure control is used The spin on filter is the same as used by most water cooled VW 4 cyl engines and the anti drain back of the Vanagon waterboxer filter 070 115 561 is helpful OEM are Mann or Mahle brand available from busdepot com 4 Anelectronic ignition distributor is used with no advance mechanism 043 905 205 N Ignition advance is controlled by the electronic Engine Control Unit 5 A combined ignition coil spark control unit is used 6N0 905 104 6 No thermostat or air shutters are used in the cooling system as the ECU controls mixture during warmup to prevent fuel washing the cylinder walls However the fan shroud design has not changed and the shutters and thermostat can be fitted by drilling and tapping the case for the thermostat mounting stud to provide better airflow for cold defrost of the windshield 7 Fuel and ignition are controlled by a Digifant 1 82 ECU system This system is unique to the air cooled engine although similar in concept and procedures to many VW cars The control unit includes non volatile memory for storing adaptation values matching the ECU to the car sensors and for storing fault codes for diagnostics System components include the following see Fig 1 for locations Parts marked with are available from US dealers a Digifant ECU J169 mounted under the rear seat on the
26. nt mounting brackets are used so the bumpers have slightly different mounting holes The older bumpers will fit by either using the old brackets which fit the body or drilling holes to fit the new brackets Except for the Ultima Edicion the bumpers were typically painted the body color with the wide black stripe Btlmex sells the chrome bumpers as used on the Ultima Edicion These are probably the best quality chrome bumpers of this style available with very good chrome plating The steel used is about twice as thick as the common Brazilian aftermarket bumpers External Trim Door hood and trunk handles are painted black on most models but can be easily changed to chrome versions Same design as used in the 70s cars If you change the handles the lock cylinders can be swapped to the new handles so the same keys will work 14 ACD Engine Diagnostics The Digifant ECU communicates for adjustments and diagnostics It is intended to use the VAG1552 or VAS5052 diagnostics tool used by VW dealerships However it does not use the now standard 16 pin DLC connector as do US models so it requires an adapter cable Although VW models sold in the USA are OBDII compatible so some diagnostics can be done with standard OBDII scan readers the Sedan is NOT OBDII compatible as it is not intended for sale in the US The cost of the VW dealer scan tools makes them impractical for the normal owner mechanic One solution is the VAG COM s
27. oftware and adapter cables from www Ross Tech com which allows a laptop computer to duplicate the functions of the VAG1552 VAG COM is available in both English and Spanish also German from the Ross Tech website Interface Adapters Adapting the Sedan diagnostics connector to the VAG COM can be done using two VW produced adapter cables One adapter converts the 16 pin OBDII socket to the older VW 2x2 connectors and the other converts the 2x2 to the special 3 pin diagnostic socket used by VW Mexico on the Beetle harness The 16 pin to 2x2 adapter typically costs about 50 and the other cable is hard to find However since only 3 wires need to be connected there are several approaches to adapt the car to a standard interface The Sedan diagnostics connector is located inside the engine compartment normally parked on a dummy connector mounted in the top left corner near the hinge for the cover To enable the car to be used only with standard 16 pin interfaces a DLC connector could be spliced in place of the 3 pin socket Because it is located in the engine compartment it should be protected by a cap and would require a custom bracket to mount the connector If this method is used gold plated contacts might be a good idea If you have an interface that will only be used with the Beetle it may be possible to replace the DLC connector of the interface with the 3 pin plug to fit the car This would depend on the way the interface is
28. oller it is a different unit Most of the engine is identical to the air cooled Beetles of the 70s and repair procedures are similar However the valves should not be adjusted periodically and are set like the T4 hydraulic lifters 0 clearance plus 1 turn compression when assembling The hydraulic lifters may bleed down and clatter a bit when the car sits but they should not be adjusted if this happens Doing so could collapse them fully and hold valves open They will pump back up with time as the oil thins with heat to work back into the lifter Idle speed is controlled electronically with no mechanical adjustments on the throttle body When fully warmed up the idle speed should be 830 760 890 rpm The Digifant ECU also limits the maximum engine speed to 5000 rpm This controlled maximum speed allows the use of the cast steel crank and flywheel The use of cast steel components is very acceptable for the stock engine and has proved as reliable as forgings with the stock power and engine speed limited by the Digifant system Modern casting methods and alloys are far superior and more consistent than when VW tried and abandoned cast cranks in early Beetle production There are two major adjustments in engine operation 1 Ignition timing which is set by turning the distributor as with older models The one timing mark on the ACD pulley is at TDC although the timing is set to 6 degrees btdc This means either a digital advance timing li
29. om out the lifter and keep the valve from seating fully This can cause poor idling and valve burning Valve clatter can occur when one or more lifters bleed down and cause excess lash clearance before they again pump up to proper operation An owner may panic when he encounters lifter clatter and re adjust the valves while the lifter pistons are partly collapsed thereby adjusting them too tightly and causing the problems noted above There will be conditions that cause lifters to bleed down see below but this is a minor issue so don t be too aggressive to over react Just drive the car fully warm and the lifters should pump up within minutes to a few days Driven sensibly there should not be damage from this condition Lifter clatter seems to be worse when too heavy oil is used When a valve stays open with the engine off the valve spring may hold enough pressure on a lifter to cause oil to seep out With a thick oil the lifters don t fill again as easily as with a thinner oil That s why you typically have to drive with a hot engine enough to get the lifters to quiet down as the oil thins when engine gets warm By using a wider range oil that s thinner when cold the lifters will pump up faster Synthetic oils also thicken less when cold and are available in wider viscosity ranges After changing our cars to 0w30 or Ow40 synthetics lifter clatter hardly ever occurs and quiets quickly if it does A Ow40 synthetic should be excellent
30. ormally stay light grey to white and if they maintain normal color the mixture is probably OK and another cause rubbing brakes tires or pressure may be indicated Mileage can also vary a LOT depending on driving style Has your son been driving the car A common complaint is that the idle speed will stay too high when coming to a stop until it is pulled down by letting the clutch drag This is probably partly due to tightening emission controls as backing down or engine braking can increase emissions if the throttle is closed Earlier ECUs B version seem to drop the idle faster Careful basic setting does seem to help this condition
31. peration Problems Symptom Possible Fault Possible Solutions Low performance surging Incorrect mixture manifold Basic Setting vacuum lines ECU pressure sensing High Idle Speed Adaptation off manifold pressure Basic Setting vacuum lines ECU sensing Irregular Idle Speed Engine Temperature sensor Replace CHT Basic Setting adaptation OXS voltage low Replace OXS High Fuel Consumption Odometer error sensor orOXS Check odometer check short or error adaptation diagnostics codes check sparkplugs perform Basic Setting Engine does not start Immobilizer fault fuel or ignition Reset immobilizer Operate fault Starter 10 sec check DTCs Check fuel pressure check spark The immobilizer is a separate box with latching relays that shuts off current to the ECU and starter if an attempt is made to start the car without keying the immobilizer Because two relays are involved it is possible for one to latch and not the other so the starter may work but the engine will not run Usually resetting the immobilizer again will cure this US Beetles are notorious for having a plastic gear in the odometer crack and slip causing the indicated distance traveled to read low If fuel consumption appears to increase always check the odometer reading over a distance to be sure this isn t the problem If fuel consumption does increase check sparkplugs for indication of a rich condition sooty deposits The ACD plugs n
32. rand new Mexican made body and running gear You could even fit the new ACD fuel injected engine replacing the troublesome fuel and ignition systems with a very trouble free electronic Digifant engine management system and with a Lambda sensor and triple catalytic converter to make the old Beetle you would be driving anyway a clean running and reliable vehicle The restored car also had improved brakes modern seat belts and seats and even an alarm and anti theft system While they did not have airbags and other modern U S mandated crash protection systems they met all requirements for the time the car was originally imported and could therefore continue to be licensed and driven The car still has the simple basic transportation feel of the Beetle with the least reliable systems replaced with solid modern technology You end up safer and cleaner than continuing to drive the car with the original aging parts so this is a real win win situation As long as none of the new electronic systems has a problem and needs to go back to a dealer in Mexico Luckily the Digifant system of these cars has built in communication and diagnostics so that a standard interface like the VAG1552 can connect and read any stored trouble codes DTCs to help find problems and can also be used to make adjustments if they are required Some procedures are common to other VAG models and some are unique to this model If replacement parts are needed it can be
33. t out The ACD injectors are not available from US dealers so consider keeping a spare Engine Removal Removing the engine is very similar to older Beetles with attention to a few extra details 1 Disconnect both fuel hoses to the engine one at the fuel filter the other at the return tube to the front Plug all open ends The fuel rails and injectors can be damaged by the bodywork around the engine seal and make removal and installation very difficult unless the rails and injectors are removed first Remove the mounting bolt from the rail and then pull the two injectors and rail out as a unit and place on the head away from the bodywork leaving the fuel lines connected Note the injectors are not fastened in the rail or in the manifold but float on o ring seals between them so they may fall out of the rails as you move them You may find it easier to remove the muffler cat assembly from the engine and heater boxes before removing the engine This gives more clearance for the engine to move to the rear to clear the transmission If you choose to do this remove the Oxygen Sensor from the cat first The electrical connector for the sensor will not fit through the grommet in the rear engine tin the sensor will fit through once removed The main electrical harness for the engine now connects with a single round connector on top of the shroud Twist the broad knurled locking collar and it disconnects the car harness form
34. ts The only instrument is the familiar VW speedometer with built in indicating lights and fuel gauge Like the rest of the world all speed and distances are in metric units The housing for the speedometer is now plastic with some differences from the old units The gas gauge now incorporates a brake warning LED behind the speedometer faceplate and the associated electronic circuitry The vibrator voltage stabilizer for the gas gauge is no longer used If the owner wants to change to a speedometer with measurements in miles the gas gauge and brake warning light will not simply fit into an older speedometer housing However the Speedometer mechanism of an older unit will fit directly in to the new housing and then the new gas gauge assembly can be maintained Only one small hole must be drilled in the old faceplate for the brake warning LED Controls Dash switches are now rectangular rocker switches as on other VW models A dual stalk turn signal and wiper control is used but the windshield washer is now an electric pump unit so the stalk no longer has a control valve for the pneumatic washer 12 The heater control is still a lever to the side of the handbrake but only one lever controlling the flaps on both heater boxes is provided There are no rear seat heat vents or defroster and therefore no controls for them Floor heating is by outlets under the doors with operating levers on each grill Close the floor vents to incr
35. y clicking the Clear Codes button to see if they reappear which would mean the problem still exists Some codes will only reappear after driving for an extended time or for more than one driving cycle The following table should be helpful in finding causes of the errors that may be reported 17 Diagnostic Trouble Codes supported by 043 906 022 E Digifant control unit Message Possible causes 00515 Hall Sender G40 Wiring or defective part Open circuit or short circuit 00518 Throttle Valve Position Pot G88 Wiring or defective part Open circuit or short circuit 00519 Intake Manifold Pressure Sensor Defective sensor tubing to G71 no signal manifold 00522 Engine Temperature Sensor G27 Defective part or corroded Open circuit or short circuit contacts 00523 Intake Temperature Sender G42 _ Wiring or defective part 00525 Lambda probe G39 No signal Wiring or defective part 00532 Supply Voltage out of range Should be 10 to 16 V 00533 Idle speed control too high low Valve N71 connector air leaks 00537 Lambda regulation out of range Probe heating Exhaust leak Ignition fault Intake leak injector fault Evap valve open high fuel pressure 00561 Fuel Mixture adaptation out of Fuel Pressure Ignition problem range Intake leak Injector fault Exhaust leak Evap valve open Ignition output short Check N571 transformer Evap Valve N80 open or short Wiring or defective part circuit Idle Sp
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