Need HELP!!!

[RAVEN13xxx]

1052851

ok 97 TJ 2.5 with 82k miles---- new plugs wires cap rotor. It has started to run really rough and missing somethin fierce. Everything checks out OK (wires plugs etc.) The ECM is throwing codes left and right about random misfires and misfire on #4. As I said all that checks out. I am beginning to think the ECM is going out. Any ideas?? Maybe it is time to do that 350 convert.

edited by: RAVEN13xxx, Jan 30, 2003 - 05:46 PM[addsig]

 

[marc]

1052852

Did you catch anycodes for fuel injectors? Or do you have any tapping noise from you valve train you could have floated/burnt a valve if every thing checks out with your ignition that would be my only guess since its only in one cylinder I wouldnt be bad gas or a clogged air filter, also can you tell if its running rich? If its running rich I wouldnt be a fuel injector because its dumping the fuel also when you checked you dis. cap how did you points look? hope i helped

marc[addsig]

 

[jcooper]

1052854

clogged/bad fuel injector? Too much or too little gas (sticks open or closed) means it won't ignite (misfire).

Platinum plugs? I've heard they don't do well in jeeps for some reason.

Cooper.



[addsig]

 

[RAVEN13xxx]

1052856

Nope no codes for injectors and fuel is fine. I had it on the Snap-On scanner at work and everything checks out. All injectors are OK, air/fuel ratio is perfect, and no noises except the backfires through the TB and the bad misses. No to the platinum plugs also.

edited by: RAVEN13xxx, Jan 30, 2003 - 06:07 PM[addsig]

 

[MudderChuck]

1052890

Just thinking out loud. Most of the newer motors run right at the edge of detonation. If they detonate, they sometimes deform a valve, looks like an insideout umbrella. If you put a little air into the suspect cylinder (about 5-10 PSI) and hold the throttle valve open you can often hear the air passing the valve. But sometimes the valve seats good enough this doesn´t happen. Compression testing will often show up low, but sometimes the valve opens just enough to admit air. One test that might help, is to check the lash, by hand and when you get to the susupect cylinder, the lash for the intake can be really (too) tight.
If the knock sensor was going out, it would probably default to a fairly low advance. If the crank position sensor, was going out it, would probably be random and not confined to one cylinder. If it was coolant leaking into the cylinder it would probably mess up your air/fuel ratio, as well as leave bubles or foam in hte cooling system.
If it is a valve and you catch it quick, simple lapping and a replacement valve will set thing straight.
Low vacumn might also be an indicator.
:-? :-? [addsig]

 

[MudderChuck]

1052893

I once found, a little puddle of water, under the mounting plate in my distributor. It was like -15 and only misfired when it was warm, drove me nuts, until I caught on. When it was hot, it was just vapor (occasional misfire), when it was warm, drops (serious misfire) when it was cold ran just fine. :roll: [addsig]

 

[idrthrbfishing]

1052900

I have a 97 2.5 with 90k Myjeep runs fine, My buddie had 97 sport 4.0 66k your problem sounds a lot like what he was going through, his cataletik converter was causung all kinds of goofed up codes as the dealer put it , they replaced it and it ran fine after,just a thought.:-? Until kid 3 came along and he had to sell it. now he is missing it every time he sees mine. :lol:

edited by: idrthrbfishing, Jan 30, 2003 - 08:52 PM[addsig]

 

[RAVEN13xxx]

1052923

Thanks for the tips...... I'll check them out tomorrow at work and let ya know what i come up with. :-( [addsig]

 

[AFholmz]

1052957

mr. fishing is right. It should be the cat. TJ's are nortorious
for pluging the cats. My cousins would even run it was so
plugged. Luckily there are bolts right behind the cat so
you can cut them and clean it out. It has a hollow sound
but its cheaper than a new $250 cat.[addsig]

 

[RAVEN13xxx]

1052974

Well, when I redid the exhaust, i made it a totally welded system..... no bolts or clamps. I believe the cat is OK.[addsig]

 

[hi_c]

1052979

O2 sensor checks out? Do the compression test on each cylinder, like Mudder said. Also check for an air leak, too much air causes misfires. I had a bolt backout of the intake manifold last year that caused it to run rough. When it gets too much air, the fuel spits more to compensate and the thing ran so hot that the leftover fuel burned up inside the Cat. The cat was glowing red one night, that's how I caught it. If it would've blown up... i would've had some serious problems![addsig]

 

[RAVEN13xxx]

1053095

IT'S FIXED!!!!!!! I checked for play in the distributor shaft, and it had alot. I replaced it and also replaced the plugs cap and rotor (wires will wait till i get the $$ for the 8mm accels). It ran better but not great. I really started thinking it was the ECM. Did a compression check and all were within 20 of each other running about 164. I checked the injectors with noid lights and that was OK. Then, checked then with a stethoscope and all were clicking. Since I was getting nothing from #4 cylinder, I put in a new injector,and....... TADA...... IT'S FIXED!!

edited by: RAVEN13xxx, Jan 31, 2003 - 05:38 PM[addsig]

 

[MudderChuck]

1053127

Air, fuel, spark and compression. Something bound to happen, when they are there, hopefully when it´s supposed to. Trick always has been, to figure out what´s missing and why. And assumptions will often get you in trouble, if I heard it clicking, I probably would have assumed it was, OK. What made you swap the injector out? Instinct or had you seen it before? Are the injectors in the newer models prone to failure? Maybe the filter has a few to many microns :lol: What do you think?[addsig]

 

[MudderChuck]

1053129

I´m thinking of getting a 98 or so TJ, 2.5 ltr. I was wondering what might be handy in the way of parts, to leave rolling around the old glove compartment? Already figured a pick-up coil, maybe crank position sensor, along with the normal ignition parts. Would an injector or two be worth it? I sometimes get called away, don´t like to fly, if I can help it. And mostly it´s a short notice type thing. Road repairs are always iffy, to sometimes non-existant.[addsig]

 

[RAVEN13xxx]

1053208

Well, it was getting spark and air but no fuel. The noid light told me the ECM was sending the signal, but no fuel going through the injector. I grounded the #4 plug wires and there was no change in rythyme... so no fuel to that cylinder. As far as spare parts.... cam sensor (under the rotor inside dis.), crank sensor, plugs, wires, serp belt, coil. The injector was kinda pricey, and only from dealer. My cost on it was about $86.[addsig]