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LTS Networking March 1999 - Linder Technical Services
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1. MARCH 1999 Network The Official Newsletter of LINDER TECHNICAL SERVICES TECH TRAIN ING Je AUTOMOTIVE INDUSTRY 7S MEETINGS SN on For the 1999 year we have scheduled the first Wednesday evening of each month as cian Tra Industry Night The J anuary meeting was snowed out but the February amp March meetings were nothing short of WOW February s meeting was held at Ivy Tech on East Washington Street and kicked off with a short group discussion introducing Mac Vandenbrink The Ignition Guru Mac held everyone s attention as he led a group discussion on Ignition Systems and used a 1999 Olds Cutlass hooked up to an older version scope 2500 Allen Unit and performed cylinder balance coil stress tests and even placed the vehicles front 02 sensor on the scope screen for all to see an analyze Ivy Tech also had some of the latest COP coil on plug vehicles on display for discussion and hands on performance testing Meeting was ended at approximately 9 30 and many stayed later to discuss various ignition testing among themselves So Next months meeting is set for Wednesday April 7th again at Ivy Tech with the topic Ford ECM Programming These meetings are a no charge meeting and are conducted at the Ivy Tech Facility Automotive Department East Washington Street Make it a point to attend the next meeting What Technical Industry Meeting Where Ivy Tech Automotive GM Classroom When Wednesday
2. April 7th Time 6 30 9 30 PM Topic Ford ECM Programming cost FREE BE THERE TOOL TIME LTS has also scheduled the first Monday of every month to be TOOL TIME TOOL TIME is a technician product review evening at our Gasoline Alley shop and the tools to be reviewed are set by the attendance from month s prior This month s tool time features the P R I INC SENSOR SIMULATOR This tool is displayed discussed and used in a hands on session Many new uses and functions will be discussed These sessions are not sales pitches and most times the manufacturer doesn t even know we are dissecting their tool TOOL TIME starts at 6 30 and runs to 9 30 each evening Come early and get involved This is a no charge session also LFS NORTH in formaron RANDY S CASE STUDY 1990 Cadillac Eldorado 4 5 LPFI 48 812 miles north VIN 1G6EL1331LUXXXXXX COMPLAINT Vehicle travels down the road at 50 mph without using the accelerator pedal It did NOT do this before YOUR tune up HISTORY The 4 5 and 4 9 Cadillac engines have an in depth idle relearn procedure that must be followed to HELP this condition GM released a bulletin for this condition in 94 PROCEDURE Key on enter diagnostic mode off and warmer key off wait 20 seconds and repeat 3 times Let engine idle w o A C for 18 minutes Idle in gear for 1 minute Idle in gear with A C for 1 minute then turn the key off and wait 20 seconds CAUSE During a routine ser
3. burn stroke and the exhaust stroke can compare and contrast the kV requirements for each firing event If it requires 10KV to fire on the burn stroke and 3 kV to fire on the exhaust stroke then the common denominator is compression Now let s say that a different cylinder requires 10kV on the burn stroke and 6 kV on the exhaust stroke What could be the problem Well judging from the other cylinders know that the plug gap minus air fuel ratio and compression only requires 3 kV on the exhaust stroke The diagnosis becomes a logical deduction that there is a small break in the plug wire upstream of the spark plug You would never see this looking at compression alone since the kV demand of the plug under compression outweighs the small break in the wire Of course there is always the snap throttle test where on decel the hydrocarbon spike eliminates the plug gap But by the time My scope loses sync and then regains it l m back at idle again Stop by the shop and try it out for yourself You ll be amazed For more information on the DiScover Il unit call Mike at Linder Technical Services 4 4 D GASOLINE ALLEY INDIANAPOLIS IN 46222 317 487 9460 OFFICE 317 487 868 FAX WEB PAGE WWW LINDERTECH COM E MAIL LINDERTECH JUNO COM We re on the web WWW LINDERTECH COM WE ENCOURAGE PROFESSIONALISM THROUGH TECHNICIAN CERTIFICATION international TNA Automotive Technicians Network MARCH 1999 FROM THE
4. DATA GROUP A Really Bad Fuel Pump Waveform tf e TTT performance problem Technician used a current probe and lab scope on fuel pump feed wire See fuel pump waveform in picture to left This has got to be one of the worse fuel pump waveforms have ever seen New pump waveform is seen on right waveform Note current draw of approximately 8 0 amps ground is first line up from bottom and rapid speed of motor with sharp voltage to commutator transitions due to the horizontal brush set up of this Carter Chrysler design pump A smaller commutator area moves past the brush contact area much faster than a vertical brush such as Delco etc with a horizontal brush contract area etc Waveform compliments Marsh Garage Indianapolis Indiana 4 LINDER TECHNICAL SERVICES
5. Il converts any ignition scope to a very comprehensive problem solver But first before examples how about a quick description of operation 1 The Box utilizes a direct connection to the secondary ignition circuit This is accomplished by Teeing into the plug wires at the ignition coils Average hookup time is l 3 minutes Even on 2 8 3 1GM Of course on these engines it is only difficult to replace the coils not snap on the plug wires Now that I m connected to the secondary circuit cylinder kill is simply achieved by throwing a switch can manually kill them or can have the Box kill them in timed mode so that may perform a cylinder balance with gasses When a cylinder is killed the spark is routed through the Boxes hookup cables through a neon bulb then to ground A neon bulb is provided per cylinder 2 LINDER TECHNICAL SERVICES yy FUEL INJECTION SERVICE A TE FROM THE INJECTION WIZARD running but the system should hold some pressure a minimum of 5 psi for at least 10 minutes If the regulator is found faulty it can be replaced separately You will notice on the fuel rail where the regulator is typically mounted a dampener The dampener absorbs the fuel pulses when the injectors open There is service port available at the rail for fuel system testing The Camaro had a clogged filter do to a local gas station having water in their tank Looking for this information found a
6. amaro had me do a little research The engine in question was the LS1 Vin G 5 7L 346 cu in V 8 The technician felt he had lew fuel pressure and was unable to find a spec to compare with Here is what I found out First of all this vehicle uses a returnless or demand fuel system This means that only one fuel line the supply line is connected to the fuel rail and no return line from the rail is used This is done to reduce fuel heating and therefore reducing evaporative hydrocarbon emissions There is a return line from the filter area to a regulator which is located in the tank at the sender unit Since no vacuum is routed to regulator the system pressure according to GM should be constant between 55 60 psi Pressure will drop after the pump stops Dynamic Auto Test ANALYSIS FROM THE ANALYSIS SLEUTH TALES FROM THE TEST LANE I converted my hand held scope into a DIS Problem Solver First of all want to say lutilize hand held scopes daily Second like you I ve found that for ignition analysis on DIS at best most will only identify a wide open plug wire Of course must go from cylinder to cylinder to find it Now comes DIS parade adapters However with parade compression and waste spark are superimposed Now still have a plug wire scope but don t have to hook to one wire at a time All of this for 500 1100 00 Instead to convert to a problem solving tool utilized the DiScover Il The DiScover
7. couple of other nice to know facts The sequential injection system uses the newer style Bosch disc type injector The injector resistance specification is a minimum of 12 2 ohms 70 deg F Also sequentially fired is the ignition system It uses the coil near plug electronic ignition which has a coil for each sparkplug The firing order is 8 7 2 6 5 4 3 this looks familiar so don t get fooled 3 On the other side of the neon bulbs are calibrated spark gaps to ground fixed at 22 kV So now if the car has an open plug wire the neon light will light up and the spark occurs inside the Box With this dont even need a scope to find the open plug wire All need to do is start the engine Aside of the tests perform without a scope when do hook my scope to the Box may display ignition patterns in three ways A may look at compression and waste superimposed to compare kV demand B Imay separate compression and waste spark for the same plugs on the same screen for the negative side of the coil C Imay do the same for the positive side of the coil Whatis the advantage of looking at compression and waste spark on the same screen Well now can see the plug fire under two different conditions What can see Let s first establish that kV demand is determined by the greatest gap in the circuit combined with the conductivity of that gap air fuel ratio t compression When I see a plug for a given cylinder fire on the
8. vice the throttle plates were cleaned causing the learned values stored in the PCM to operate the ISC as if the deposits were still present We suggest NOT cleaning the throttle plates on these engines during regular maintenance procedures The relearn TSB will only drop the speed to 20 mph not cure the condition completely Only weeks of driving will cure the complaint FUEL PUMPAMPERAGE DRAW TEST The fuel pump amperage draw test can be a useful test when diagnosing fuel pump concerns The tests are broken up below depending on the type of engine you are working on High amperage usually indicates a bound fuel pump Low amperage usually indicates a problem in the wiring 1 Make sure the key is in the OFF position 2 Disconnect the fuel pump relay if not equipped with a prime connector 3 Set the DVOM to the amps scale and connect one test lead to battery power Connect the other test lead to the prime lead fuel pump side of the relay cavity The following data is rule of thumb as to what is good and what is not T B I engines 2 to 4 amps PFI engines 4 to 6 amps C P I engines 8 to 9 amps 5 7L Engine Pictured is the 1996 VIN P Consult your service manual for other models VIN P PCM 2 U H r 440 ORN PCM BATTERY FEED 15 AMP 440 ORN PCM BATTERY FEED FUEL PUMP PRIME CONNECTER TO FUEL PUMP 120 GRY 350 R FUEL PUMP FP RELAY U H 2 LINDER TECHNICAL SERVICES A question about fuel pressure on a 1998 C
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