tychoS Posted January 27, 2021 Share Posted January 27, 2021 (edited) DII 2002 V8 4,0 Motronic When pushing the engine to perform, it misfires badly. Eg. when trying to accelerate briskly from 100 to 130 km/h, the engine will most often misfire, loose its will to accelerate, and only reach say 115 km/h. When cruising at 110 km/h it will sometimes start to misfire and the speed drops down to 100 or 95 km/h. At other times it will happily drive at 110 or 130 km/h for quite a while without misfiring. Replaced during 2020 by myself: camshaft(LR), hydraulic lifters(LR), timing chain(LR) + sprockets, injectors (Bosch), sparkplugs(NGK) The camshaft was well past its prime, as were the other parts. Replacing all these parts took the engine from undriveable to working ok, unless I push it above say 75% or so. I did the replacements in increments, and each increment made the engine perform significantly better/less badly. So whats likely to be the next step? I could keep on replacing parts, the next step would be either the ignition coils+leads or the lambda+maf sensors. But I am wondering if the problem could be elsewhere, eg. either the ECU itself or the wiring harness for it. How to best diagnose? Nanocom has this sorry story to tell: P0134 = LAMBDA SENSOR UPSTREAM CATALYST BANK 1 DRIVE CYCLE C OCCURED 21 TIMES SIGNAL INVALID P0172 = MIXTURE ADAPTION FACTOR FRA BANK 1 DRIVE CYCLE C OCCURED 1 TIMES SIGNAL TOO HIGH P0175 = MIXTURE ADAPTION FACTOR FRA BANK 2 DRIVE CYCLE C OCCURED 1 TIMES SIGNAL TOO HIGH P0300 = EMISSION RELEVANT MISFIRE MULTIPLE CYLINDERS DRIVE CYCLE C OCCURED 2 TIMES SIGNAL TOO HIGH P0303 = CATALYST DAMAGING MISFIRE CYL 3 DRIVE CYCLE C OCCURED 64 TIMES SIGNAL TOO HIGH P0305 = CATALYST DAMAGING MISFIRE CYL 5 DRIVE CYCLE C OCCURED 64 TIMES SIGNAL TOO HIGH P1000 = EMISSION RELEVANT MISFIRE CYLINDER 2 DRIVE CYCLE C OCCURED 2 TIMES SIGNAL TOO HIGH P1000 = LAMBDA SENSOR UPSTREAM CATALYST BANK 2 DRIVE CYCLE C OCCURED 7 TIMES SIGNAL INVALID P1300 = CATALYST DAMAGING MISFIRE MULTIPLE CYLINDERS DRIVE CYCLE C OCCURED 66 TIMES SIGNAL TOO HIGH P1668 = ANTI-THEFT ALARM SERIAL LINK FAULT DRIVE CYCLE A OCCURED 1 TIMES SIGNAL TOO HIGH NA OCCURED 65 TIMES SIGNAL TOO LOW FAULT IS CURRENTLY PRESENT NA OCCURED 193 TIMES SIGNAL TOO LOW FAULT IS CURRENTLY PRESENT NA OCCURED 0 TIMES SIGNAL TOO LOW FAULT IS CURRENTLY PRESENT Edited January 27, 2021 by tychoS Quote Link to comment Share on other sites More sharing options...
elbekko Posted January 28, 2021 Share Posted January 28, 2021 I'd clear the faults, reset the adaptive values, and drive around while keeping an eye on the lambda values. If a lambda isn't switching, it can really screw with the tune (been there, done that). Quote Link to comment Share on other sites More sharing options...
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