Fuel system - Troubleshooting
Contents
1. Check compression See ENGINE MANAGEMENT Fuel Lack of compression Fuel injection 6 23 Fuel system Troubleshooting COMPLAINT Oil pressure warning light stays on POSSIBLE CAUSE Low oil level Failure to carry out daily check and top up Short circuit Switch faulty Blocked Oil pressure switch POSSIBLE FAULT ACTION TESTS Top up and carry out recommended daily check top up Trace leak repair as necessary Disconnect lead from oil pressure switch Switch on ignition If oif warning light remains on there is a short circuit Fit and connect new switch Run engine If light goes out leave new switch on position Renew filter Dirty or defective Clean or renew valve Oil strainer Biocked Excessive clearance Examine renew if defective Examine renew if necessary 6 24 Fuel system Troubleshooting COMPLAINT Abnormal noise from engine top end POSSIBLE CAUSE POSSIBLE FAULT ACTION TESTS Tappets noisy Adjustment too Adjust correctly slack Oil feed to Clear restriction valve gear restricted Check compression Test 1 Loose valve Dismantle check and repair guide s as necessary Tapping or rattling from top end 6 25 Fuel system Troubleshooting Test 1 Compression Note This test can only be carried out with the battery in good condition 1 Start engine if possible r2. dry Slowly rotate tester handie to create a pressure 10 bar below injector opening pressure Hold pressure for 10 seconds check nozzle It should be dry If injector fails to meet any requirement in 2 3 or 4 renew injector 19M 0026
3. D 4 vO m f a E si PR os f uit nd k p ie ie eaten J es Fi 4 1 aO a l n Ras i 5 a i f ae L q i ATIC t Ea LN as s A AD MINA mete Ay O Pu e AE A 19 ie O Y ff WN f t uy y A et N 4 MA 3 ae A MA Vy M AY SN y 10 ELN A F AN D 4 6 29 Fuel system Troubleshooting 6 30 COMPLAINT Engine will not start POSSIBLE CAUSE POSSIBLE FAULT ACTION Stop start Remaining in See appropriate Electrical solenoid stop position Fault Finding Manual in fuel system Bleed fuel system Blocked Clean filter renew element Fuel filter Check performance Check correct timing Check pump performance repair renew as necessary COMPLAINT Engine misfires will not idle correctly Fuel injector s Defective Injection pump incorrectly timed Worn defective POSSIBLE CAUSE POSSIBLE FAULT ACTION In fuel system Bleed fuel system Air cleaner Blocked Renew air cleaner element Dirty Clean filter renew element Fuel injector s Check performance injection pump Idling stop out Adjust idling stop of adjustment Incorrectly Check correct timing timed Worn Check pump performance defective repair renew as necessary Fuel filter TESTS TESTS Fuel system Troubleshooting COMPLAINT Engine lacks power POSSIBLE CAUSE POSSIBLE FAULT ACTION TES
4. Fuel system Troubleshooting FAULT FINDING COMPLAINT Engine will not start Engine misfires will not idle correctly Engine lacks power Excessive exhaust smoke Oil pressure warning light stays on Abnormal noise from engine top end 6 21 Fuel system Troubleshooting COMPLAINT Engine will not start POSSIBLE CAUSE POSSIBLE FAULT ACTION TESTS Starter motor See appropriate Electrical Fault Finding Manual No fuel in tank Check replenish fuel tank Glow plugs inoperative Check glow plugs and circuit Fuel injection inoperative or See ENGINE defective MANAGEMENT Fuel Check compression COMPLAINT Engine misfires will not idle correctly Does not turn engine Lack of compression POSSIBLE CAUSE POSSIBLE FAULT ACTION TESTS Fuel injection Intermittent on See ENGINE one or more MANAGEMENT Fuel cylinders Lack of Check compression compression 6 22 Fuel system Troubleshooting COMPLAINT Engine lacks power Note Ensure brakes are not binding POSSIBLE CAUSE POSSIBLE FAULT ACTION TESTS Throttle cable Adjust cable Fuel injection Defective See ENGINE MANAGEMENT Fuel Mechanical Check compression Repair renew as necessary Turbocharger if fitted Repair clear pipe sensing pipe COMPLAINT Excessive exhaust smoke POSSIBLE CAUSE POSSIBLE FAULT ACTION TESTS Air cleaner Renew air cleaner element
5. TS In fuel system Bleed fuel system Dirty Clean filter renew element Defective Check performance Check correct timing Check pump performance repair renew as necessary COMPLAINT Excessive exhaust smoke Fuel filter Fuel injector s Incorrectly Injection pump timed Worn defective POSSIBLE CAUSE POSSIBLE FAULT ACTION TESTS Fuel injectors Check performance Injection pump Check correct timing Check pump performance repair renew as necessary Incorrectly timed 6 31 Fuel system Troubleshooting 6 32 Test 1 Injectors injector tester DX710 illustrated Note To identify faulty injector run engine at idle speed Slacken and tighten in turn each injector high pressure union No change in engine speed while a particular union is loose indicates that injector not performing correctly Y 2 Engine stopped remove suspect injector from engine and connect to tester Checking injector opening pressure Rotate tester handle and note pressure at which injector operates it should be Normally aspirated engine 125 5 bar Turbocharger engine 130 5 bar Checking spray pattern Rotate tester handle fast enough to operate injector 4 or 5 times per second Spray pattern should be finely atomised uniform in shape and should not contain splits or solid fuel A slight centre core ts permissible Checking for dribble Wipe injector nozzle
6. ct yellow lead of tester to threaded portion of glow plug Press test button and note ammeter reading Keep button depressed and note time taken for ammeter reading to stabilise Compare results with figures given in Test 2 fy 2 305 a 1 GOW Bigg TESTERA woli 6 26 Fuel system Troubleshooting Test 4 Relay and timer circuit 1 Switch off master switch and disconnect supply lead from glow plugs Connect read lead of glow plug tester to supply lead and connect black lead of tester to battery negative terminal 2 Connect yellow lead of tester to a spare glow plug fitted in top of tester Press and hold test button while switching on master switch and note ammeter reading The reading should start to fall towards stabilised figure and drop to zero as timer breaks Circuit a 19M 0025 6 27 Fuel system Troubleshooting FAULT FINDING COMPLAINT Engine will not start Engine misfires will not idle correctly Engine lacks power Excessive exhaust smoke COMPONENT LOCATION 1 Fuel heater 5 Fuel injection pump 2 Fuel injector 6 Air cleaner 3 Glow plug 7 Fuel filter 4 Intercooler turbo charged engine only 8 Turbocharger 6 28 O sj O O sl Y 2 OQ O L pur 102 gt Y gt LL 9 j Ve gt all Ne l E E ps A MD pe SA EN Whe gt oe al MA Pee p e as z oe ye A i y ie to E ee
7. un it until it reaches normal running temperature stop engine 2 Disconnect lead from shut off solenoid on injection pump 4 Fit adaptor of a diesel compression tester into No 1 glow plug position Connect compression tester 5 Operate starter motor until gauge reaches its highest reading record reading and remove adaptor 6 Repeat operations 4 and 5 for remaining cylinders and compare readings All reading should be within 10 of each other and should all be above 25 5 bar 370 75 Ibf in2 3 Remove glow plugs Test 2 Glow plug in glow plug tester Tester DX300 illustrated 1 Connect red lead to battery positive terminal and black lead to negative terminal 2 Fit glow plug into tester and retain with spring Sm 7 A loaded bar Connect yellow lead to threaded tine NA portion of glow plug y J 3 Press test button and note ammeter reading Keep button depressed and glow plug tip should start to glow after 5 seconds 44 CAUTION The glow plug tip must glow first If it fails to do so replace glow plug 4 Ammeter reading should show initial current draw of 25 amps which should fall to 12 amps after 20 seconds ii oP A e a Test 3 Glow plug in engine 1 Switch off master switch and disconnect sf m electrical leads from glow plug s to be tested XM 1948 Connect red lead of glow plug tester to battery positive terminal and black lead of tester to negative terminal 2 Conne
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