Todays 2.9 puzzle

[sspencer82]

'88 2.9 starts and runs fine for 3 seconds, "check engine light" comes on, rpm drops.
Yes this is the same engine from 'Stuck at 3K'... the thing will NOT go into tune like it should. Doesn't matter whether PIP plug is in or out...no change. The engine has no power. Have to turn radio up to drown out the valve clatter when accelerating.

 

[Psychopete]

'88 2.9 starts and runs fine for 3 seconds, "check engine light" comes on, rpm drops.

Hard to say.. I would start on that by pulling codes since the CEL is coming on, and checking the fuel pressure to make sure it's in spec.

 

[jhammel85]

Have to turn radio up to drown out the valve clatter when accelerating.

..Hmm. Yeah I would start with codes too but, Perhaps the distributor is loose and knocked itself out of time???

Is it possible the valve chatter was actually pinging from detonation?

Just an idea..

 

[sspencer82]

It's been spitting out 3 codes: O2 (always did that), PIP, and I forget the 3rd one. Haven't checked codes on it since Jeep went down. It has a new pressure regulator, relatively new TPS... Could it be the re-man computer? Could it need to be reprogrammed? The engine was re-built last year, should be roaring instead of sputtering

 

[jhammel85]

The PIP code could be tripped by the sputtering but an 02 sensor can cause this too. Especially the bogging down. Unplug it and give it a ride around town...See if it still does it.

I guess it could be a CPU problem but I would try to find out whats up with the O2 or its circuit.

 

[sspencer82]

distributor is tight...I'm thinking electrical/ computer issue

 

[Psychopete]

If it's o2 sensor lean code, a lot of times it really is sensing too much oxygen in the exhaust. Misfire, vacuum leak, etc can all cause this code. Something funny in the ignition could be causing a mis-fire. Think you should try and tackle the code 14 first, clear codes by pulling the jumper while the stored memory codes are being output, and wait and see if that resolves the o2 sensor code. Were those just stored memory codes, or did you run through the KOER test?

 

[sspencer82]

what jumper? I did KOEO... this thing has had 3 O2 sensors in the past 3 years

 

[Psychopete]

Are you using a code scanner or doing it manually with a jumper wire at the diagnostic connector?

Probably not the o2 sensor then unless it's a wiring issue, but mostly bad o2s will cause problems when the engine is up to temp. Think it's likely it's sensing too much oxygen, seen this senario many times. The codes don't always point to a specific sensor at fault, but that what it's reading is out of range of what it's suppose to be.

 

[sspencer82]

Code reader...I do get code 14