Geez ... wish it would be the CPS ... or fly ... When I had a CPS go out; it had no driveability symptoms though ... would be going alone fine ... then chug chug ... dead. Would restart later drive fine for a while then repeat the same stuff.

I can't remember if you've said already cuz there are so many responses and I have to finish the install of my new KC fogs before it gets too hot in the garage .... but ... are there any codes? Check engine light on? On and off?

 

After the post about the flywheel, I got to thinking about the fact that my fiance replaced the CPS. I didn't know what year he got so I asked him and he said the CPS he got was out of Jyard and he thinks it came from a 91.Now I called the parts store and they said 88-90 have the same CPS and flywheel. So I am thinking maybe since he didnt get the right year CPS that could be a problem. I found a new 1 in stock at Autozone so I will be heading out to get that later today after work. Cross your fingers that this is the problem, if so it would explain ALOT. I will let ya kno.

 

a 91 cps will not plug into an 89 harness,they are two different plugs.the flywheels are the same from 87-90 and 91-95,as long as what you have is all from an 87-90 you are fine.
In 91 when chrysler took over the jeep name they changed the control system and wanted to make sure that no part of the old renix could be used with there system,so they cahanged all conectors and controls so they were not interchangable,the flexplate on an 89 has many little square holes on the tone ring where as the 91 has longer rectangular holes and farther apart.

 

ahh crap. i doubt the CPS thing. i have an 89 xj, 94 zj motor 91 aw4 and my cps is for a 91 aswell.

 

No, no check engine light.

I put an 88 cps and the flywheel is from my 88.

So I put in the new cps improved a bit but didn't fix problem. ALL injectors are spritzing just fine, also checked injector wires. They are color coded and I think 2 were switched somehow, we never took it apart. Once switched, ran better still not good.

Can someone take a pic of the motor of an 88 or 89? I am trying to figure out the vac lines. I have the manual but its not that great IMO. I just need a good detailed clear close shot of a complete motor.

Didn't do compression tonite as we forgot the tester at home.

 

my 90 cherokee idles fine but once you give it gas it spudders and backfires. what is wrong?

 

helps some, that's good, right? ... let's hope it's not in that cyl head .... and if it is, let's hope its a rocker arm too tight or something nice and simple. There ain't much left ...

Don't you think it's odd that the check engine light isn't on? I don't really understand that amid all the misfiring and such ... anyone else have any ideas on why no CE light?

Unless ... it's just gone out on it's own and the codes are still in the PCM?? I'll get back to that in a minute ...

Just curious ... it's kinda hard to check injectors without a bench ... did you see the spray pattern? or just feel the click ??? If you saw the pattern, were they a nice little cone shape or did they piddle, drip or squirt a stream ??? Good find on the wires too

You're right about the Haynes ... only marginally helpful ... never seems to have exactly what I want ... looks better for Renix's though than HOs. I also have Alldatadiy.com online also.... and it ain't much better .... HUGE gaps from the factory manual ... sorry *** ... oppps ... s'cuse me.

Can you borrow a OBD tester and run the codes? Be interesting to see what is hangin' out in there .... and yes, by all means redo the comp test the way I explained ...

MY KC Slimlite fogs are on, wires hidden ... and KICK AZZ !! I can actually see to drive at night on these dark, deer laden roads ... !! I coulda' changed out a motor quicker I think though ... what PITA

JPman ... try starting a new thread on that one please , you'll get more hits and answers quicker. Your question is really burried deep in here ... I mean down deep

 

Karen, you might try disconnecting your exhaust. A plugged catalytic converter can act like a potato in your tailpipe, making your motor suffocate. I wonder if your old motor wasn't the culprit, and rather the fuel delivery or exhaust... Does it have an EGR valve, and have you replaced the oxygen sensor? If its a new motor I assume you pulled the battery but you might disconnect the negative cable and touch it to the positive for 30 seconds to drain/reset the ECU.

 

Please try to read the codes first

 

That's awesome. I need new lights on my car so I can see.The exhaust was removed and did not help any, so cat is good. Have not replaced 02 sensor yet.How do I read codes? I don't know anyone with the OBD to fit. Is there another way?The injectors kinda spit out a stream in a varied sequence. Tried to watch it and get the order in which it worked but its too fast. Think it might be same as firing order.I'm about fed up with this jeep

 

Yes I believe there is another way to read the codes by switching the key off and on in a certain sequence and counting flashes of the CE light, IIRC, but I can't find the instructions now, so forget about it.

If it were me, I'd tap one of those shops that you paid to help you or TRIED to help you to borrow one. Smile nicely at them ... offer to leave a deposit ... whatever works for you. Autozones used to let them out that way, but in Cal they stopped that practice citing some coccamammie state regulaltion of which California has no shortage. The key to the codes is in the Haynes.

If you can borrow one, run the codes, write them down and then clear them. Run the motor for a while then re read the codes and write any you find down .... then and only then; return the OBD II checker.

If you can't borrow one anywhere, here's a link...

http://cgi.ebay.com/ebaymotors/U480-...QQcmdZViewItem

Harbor Freight used to have 'em too ... cheap.

NEXT, injectors need to spray a fog in a cone like pattern. If a stream or drip comes out, they need penicillin. NO ... just kiddin' ... they need cleaning. Gotta be a fog or cone. This could very well be the problem or at least ONE of them. Find a shop with a bench and take them in for cleaning. In Cal we have a company called "Injector Corrector" ... which I lovingly refer to as "Infector Deflector"...

 

I have an OBDII, I thought I needed an OBDI?And how bout the ECM? Should I try 1 from the Jyard for now and see if it makes a difference? My bro power washed the entire inside of the engine bay before putting in the new motor. COuld the washing have screwed something? Also do the ECM for the 88 jeep need flashed? When I got a new computer for my car I had to have it flashed in order for it to work.Or EGR valve or egr solenoid need replaced? 02 sensor?

 

Geez ... maybe it is OBD I ?? ... the plugs are different, I THINK ... look and see. Borrow and OBD I if that's what it takes.

Sure, go ahead and try an ECM if it's free to do so ... I'm just not an expert on this year. Motors and diagnostics in general ... yes. Don't know for sure about the flashing either ...

Yes the power wash could have screwed something up depending on how carefully it was done ... I do it, myself, but I'm really careful. In light of that fact, I would unplug EVERY connector, carefully inspect, clean and grease each one with dielectric silicone grease.

 

So I did the compression test again just like you said and all reading are from 138-151 (I forgot the paper so I don't remember exactly what order)

I did some checking and found a couple vac lines that my bro replaced WRONG so I followed the book and got them all hook back properly. Sounds much better but still backfiring.

I couldn't locate an OBDI reader so my bro told me to test it by counting the flashes. In a previous post it was questioned about the CE light. Well, the bulb was out! I replaced it and it is staying on. The guys tried to do the test with a paper clip in the diagnostic connector and it arced and got hot (burned his finger). We also tried to readjust the timing again by the book cause I found it in the manual and tried to make sure it was done properly. Anyway, no the jeep will not start AT ALL. We are not getting spark to the coil at all.

How do you test the ICM? What reading should we be getting? Could they have fried the PCM? Is there a way to test that? I need the jeep running by Sun if I can cause I gotta move the jeep out from where it all.

Is the ECU the same as PCM & ECM?

 

like the motor is good then. At the very least we can ELIMINATE compression as an issue. That is a HUGE step forward. Count yer blessings. If you can't find a OBD checker, that is sad. Someone in your area must be able to test it. It would be WONDERFUL to be able to see what the PCM or whatever you call it ... lol ... I'm lame on this model year, ain't I? ... lol .. has to offer in the way of trouble codes. Could lead us right to the offending sensor ... or not.

Perhaps you could still borrow the spare PCM from the boneyard? Doesn't sound good regarding the arcing and burning of the fingers ... I don't know how that test actually works, only that I thought it could be done.

Once it runs again, you can look at the the timing marks under a timing light and tell us what you see? Is the timing within spec. Check the Haynes for the number.

Also since there was a manifold replaced, you can check for vac leaks with either, a can of carb spray or an unlit propane torch. Lets get it running again and I'll explain how to do that test if you don't already know.

Also what did you decide to do on the injectors? Are you able to find a shop to clean them. If not there is always the option of a pretty heavy dose of SEAFOAM in the gas .. not quite as good as a MotorVac but better than nothin. Not too much gas in the tank right?

Glad to hear, K ... let's get it runnin again. You could search this forum for answers on flashing that PCM to reset it too ... bet it's here somewhere.