1985 L98 Multiple Codes
Thread Starter
4th Gear
Joined: May 2014
Posts: 4
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From: Gray Maine
1985 L98 Multiple Codes
Not sure where to begin with this car. Picked it up in a trade for a motorcycle I had over a year ago. For the first 3 months it ran great. Not sure the history of the car but it seemed pretty solid when I picked it up.
It just suddenly started running like crap last year I couldn't keep it idling or evening running, it would pop sputter and backfire. It just happened almost instantly. Pulled the codes and it pointed to either a bad O2 sensor, bad egr temp sensor or bad ECM.
Replaced o2 first, no change, tested egr temp sensor, it was testing n/c. Replaced it and engine ran and idled decent, compared to how it was.
Been driving the car off and on for several days, erratic idle to point of stalling at times and hesitates and bogs out if I get into the throttle. Pulled 9 codes tonight, 25, 34, 35, 42, 43, 44, 51, 54, 55. It seems like most could be caused by the ECM and the way it happened suddenly leaning to changing out the ECM first. Looking for any input.
It just suddenly started running like crap last year I couldn't keep it idling or evening running, it would pop sputter and backfire. It just happened almost instantly. Pulled the codes and it pointed to either a bad O2 sensor, bad egr temp sensor or bad ECM.
Replaced o2 first, no change, tested egr temp sensor, it was testing n/c. Replaced it and engine ran and idled decent, compared to how it was.
Been driving the car off and on for several days, erratic idle to point of stalling at times and hesitates and bogs out if I get into the throttle. Pulled 9 codes tonight, 25, 34, 35, 42, 43, 44, 51, 54, 55. It seems like most could be caused by the ECM and the way it happened suddenly leaning to changing out the ECM first. Looking for any input.
Team Owner
Joined: Sep 2003
Posts: 25,413
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Earlier ECM's responded to 'tap tests' to reveal maybe a bad ECM or maybe just failed solder joints to the internal boards. Clear the codes again and I'd consider some 'tap tests'.
GOOGLE "ECM TAP TEST" and interpret as you wish. If the car is a keeper there are I believe upgrades to later ECM's that were generally considered more reliable. There should be many interesting reads.
GOOGLE "ECM TAP TEST" and interpret as you wish. If the car is a keeper there are I believe upgrades to later ECM's that were generally considered more reliable. There should be many interesting reads.
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