Check engine and running like crap

I got the check engine light on my way home from work this morning. I was most of the way home and the jeep was running great, in about 3 seconds it started misfiring and I had the check engine light. Anybody have any great ideas?

92 4.0 AX15

Take it to Autozone and they can tell you what is wrong. It won't cost you a thing.

Your Jeep has user-accessible diagnostics. Do the key trick: ignition on - then off-then on-then off-then on and leave it (engine not started in this procedure). You should then get a series of flashed codes from the check engine light. Be ready with a pencil or something to write them down. Each code is two digits. The normal end of sequence code is "5-5" and the common code for recent battery disconnection is "1-2." Any other code is a trouble code. You can then go on line HERE and get an idea of what the code is for. If it's undecipherable or not on the list, you can post back here and somebody with a more Jeep specific manual can probably help.

e.t.a. It occurs to me that this comes up so often and we keep steering people to Allpar for generic Chrysler codes; one of these days we should get everyone who has a FSM to list the codes, and do an OBDI code list for the FAQ so we can send people locally.

thanks just did that.

It gave Me

33, 52, 72, 15, 12, 55

33 is ac I don't have ac so I'll ignore that one

52 Oxygen sensor stuck at rich position (looks like a possibility)

72 isn't anything on that page so IDK (any ideas?)

15 No speed/distance sensor signal (I wasn't moving so I don't think that matters)

12 recent battery disconnect

55 end of codes

here is the vid I took, if someone could confirm what I just listed that would be great

I had a 90 shadow that
burped the codes the same way:
I see 12 35 27 31 51 11 55

If codes are set, the 1st set will always be a 12, the last set will be 55

allpar.com reads as follows

35=cooling fan ckt open/short
27=Injector problems (long description)
31=bad evap solenoid
51=o2 sensor lean
11=no ignition reference or timing belt skipped

WaXJ_Skier said:

thanks just did that.

It gave Me

33, 52, 72, 15, 12, 55

33 is ac I don't have ac so I'll ignore that one

52 Oxygen sensor stuck at rich position (looks like a possibility)

72 isn't anything on that page so IDK (any ideas?)

15 No speed/distance sensor signal (I wasn't moving so I don't think that matters)

12 recent battery disconnect

55 end of codes

Click to expand...

Joe,
on some Mopars Code 72 is a catalyst efficiency code, basically saying the cat is operating below its required level. I havent seen anything with it referenced to jeeps. You just did a tune up right? Double check all your plug wires are tight and haven't worked loose. I would guess that your misfire is more the cause of the codes than the result.
-Ryan

That's a lot of codes. My first suspicion is that there's a wiring harness or connector problem or something else going on, especially if it's throwing codes for things you don't have.

My 95 FSM doesn't list 72 either. Have you had the battery disconnected within the last 40 or so starts? If not, then code 12 might be telling you that something else has interrupted the power to the PCM.

First thing I'd do is go through all the connectors - unplug and replug and check for corrosion, etc. Make sure if you've been driving in really bad weather that the big connectors on the PCM haven't become wet. My 95 tends to flood the bottom of the connector in very hard rains. It's never given codes, but a big enough downpour kills the tach signal, probably because it's at the bottom front of the connector.

have you guys looked @ that video? I'm pretty sure that I listed whats there but already somebody else has seen something different than what I saw. Yes my baterry has been disconnected recently.

Thanks for all the help guys, it was a loose connection on one of the injectors. now it only pulls a 12 and 35. Both happen to be true so no worries. I never have had an electric cooling fan until now and its not quite wired corrrectly yet so that would explain the 35.

If its going to set codes, the 1st code will be the 12, and the last will be 55
I listed them in the order I saw them on the video. I don't know if you did or not? Glad to see you got it fixed regardless....