Hello. I'm new here. I have been working on vehicles most of my life, and currently do it for a living and holding 1 ASE cert (A4). I personally own a 1988 Pathfinder 4x4 and love going out on a good trail. More about that some other time.
Got doozy in the shop right now, a 92 FJ80 with the 3FE engine, thats got me pulling my hair out. Mitchell and IdentiFix have very limited amount of diagnostic information and not very many service manual bits.
CEL on. It's running rough with random multi-cylinder misfire, black/gray sooty exhaust indicating rich condition, and strong exhaust smell that makes your eyes water. I don't see any oxygen sensors in the exhaust piping? Performed vapor test, found a couple vacuum leaks, fixed them and no change. No exhaust leaks found. Have codes for AFM and TPS. Initially also had a code for IAC, but found IAC to be stuck open, replaced it and that code did not reset after clearing, but no significant change in running condition. More on TPS and AFM in a moment.
EDIT: Also when vehicle arrived it had TPS and IAC unplugged, and all the vacuum lines on the throttle body side of the plenum were disconnected completely and laying on valve cover. These issues were corrected first and foremost, but did not make a significant change.
Engine will crank, start and rev okay, revs up to about 3000 RPMs, then the engine will stumble violently, pop and shake and wont increase past ~3K RPMs. Verified fuel pressure, checked and replaced spark plugs (old plugs looked lean instead of rich???), wire set, cap and rotor, ICM, no change. Verified cold start injector is not leaking. No fuel coming out of fuel pressure regulator vacuum line. TPS and AFM look to be recently replaced.
If I unplug the TPS, engine idles just a hair better (exhaust still indicates rich condition), and when I rev up the engine there will be fuel cut (like a limp mode rev limiter) around 2800-3000 RPMs and will not go past 3K, if I plug the TPS back in it will do what I mentioned above and run a little worse. Noticed that TPS adjustment is maxed out to the left. If I try to adjust it even a little the idle just shoots up (not sure if that's normal for these?) Swapped TPS with a good part and no change, code returns after clearing with both TPS. Connector and wiring look okay.
If I unplug the AFM engine idle rises to about 2000 RPMs and stays there for a about a minute then stalls. If I try to rev with the AFM unplugged the engine stalls. (Again not sure if this is normal for unplugging AFM??) AFM looks clean and flap is not stuck. Connector and wiring look okay.
Before I just throw a AFM at this thing, (hard to find in the shop portals) I need to research and find information about the EFI system on these particular vehicles. So far not much is turning up... Where can I find a downloadable FSM? Does this EFI system even have a limp mode? Is it really as simple as a bad AFM??
Got doozy in the shop right now, a 92 FJ80 with the 3FE engine, thats got me pulling my hair out. Mitchell and IdentiFix have very limited amount of diagnostic information and not very many service manual bits.
CEL on. It's running rough with random multi-cylinder misfire, black/gray sooty exhaust indicating rich condition, and strong exhaust smell that makes your eyes water. I don't see any oxygen sensors in the exhaust piping? Performed vapor test, found a couple vacuum leaks, fixed them and no change. No exhaust leaks found. Have codes for AFM and TPS. Initially also had a code for IAC, but found IAC to be stuck open, replaced it and that code did not reset after clearing, but no significant change in running condition. More on TPS and AFM in a moment.
EDIT: Also when vehicle arrived it had TPS and IAC unplugged, and all the vacuum lines on the throttle body side of the plenum were disconnected completely and laying on valve cover. These issues were corrected first and foremost, but did not make a significant change.
Engine will crank, start and rev okay, revs up to about 3000 RPMs, then the engine will stumble violently, pop and shake and wont increase past ~3K RPMs. Verified fuel pressure, checked and replaced spark plugs (old plugs looked lean instead of rich???), wire set, cap and rotor, ICM, no change. Verified cold start injector is not leaking. No fuel coming out of fuel pressure regulator vacuum line. TPS and AFM look to be recently replaced.
If I unplug the TPS, engine idles just a hair better (exhaust still indicates rich condition), and when I rev up the engine there will be fuel cut (like a limp mode rev limiter) around 2800-3000 RPMs and will not go past 3K, if I plug the TPS back in it will do what I mentioned above and run a little worse. Noticed that TPS adjustment is maxed out to the left. If I try to adjust it even a little the idle just shoots up (not sure if that's normal for these?) Swapped TPS with a good part and no change, code returns after clearing with both TPS. Connector and wiring look okay.
If I unplug the AFM engine idle rises to about 2000 RPMs and stays there for a about a minute then stalls. If I try to rev with the AFM unplugged the engine stalls. (Again not sure if this is normal for unplugging AFM??) AFM looks clean and flap is not stuck. Connector and wiring look okay.
Before I just throw a AFM at this thing, (hard to find in the shop portals) I need to research and find information about the EFI system on these particular vehicles. So far not much is turning up... Where can I find a downloadable FSM? Does this EFI system even have a limp mode? Is it really as simple as a bad AFM??
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