I just did a tune-up on my '97 beast this weekend, and was enjoying the heap purring like a kitten. Nice.

Then I managed to get myself involved in some other people's drama yesterday on the way home from work, and that involved letting the Jeep idle for a few minutes. My e-fan isn't working (planned project for this weekend) and it hit the 260 mark. I got it shut off, and it was able to sit for maybe 4 or 5 minutes, then on the road again, and it cooled down.

But, it's running very raggedly, sometimes smoothing out with a lurch, then back to ragged.

Any suggestions on what to look at first? What components would most likely have been compromised by the heat?

Yes, I'll be doing a compression test. *sigh*

 

Compression test is good!

Either 150 or 145 on all cylinders. That works.


TPS is suspect - it sweeps from .90 to 3.88. According to The Walker Himself, I should see:


So, new TPS in hand, and I'll swap it out tomorrow. My reader is also throwing an interesting code: P0351 - Ignition Coil "A" Circuit Primary/Secondary Malfunction.

Hmmm. Brand new coil from NAPA. I'm thinking the compression test set that code. I had the coil disconnected while cranking, of course.

I'll install the new TPS in the morning, and see what happens.

 

Good luck. Interested and following.

 

Well, that's that!

The TPS turned out to be a large part of the problem. Once I had it in, the misfiring was MUCH less. I did a test run and it was night and day. So, no question, the TPS was bad.

However, that, "P0351 - Ignition Coil" code was still there. So, swapped in a new coil, and cleared that up. Running fine, no codes. (I love having my own code reader!)

There you have it, folks. A momentary overheat condition (I almost hit 260) was not enough to damage the engine (so says the compression test), but it toasted two critical components; the TPS and the coil.

The coil was brand new (NAPA), the TPS (OEM) was replaced a year ago, so they should not have been hanging on the ragged edge of functionality.

By the way, in the middle of all this fooling around I verified that my e-fan works if it has power, installed a manual switch on the dash, and verified that it works perfectly.

Then on the last test run the e-fan died.

Oh, well, that's Jeeps!

 

Why did it over heat that fast Mark?

 

No e-fan, and I'm pretty sure my fan clutch is shot. I have one waiting in the garage, along with a water pump and t-stat. I think I'm going to go ahead and do the hoses and radiator while I'm at it. It's cheap insurance.

I had been driving for over an hour, so everything was well heat-soaked, so idling for a few minutes after driving very slowly for about 5, was all it needed.

 

You should be good to go after you do all of that.

 

A good example to learn by for everyone: Deferred maintenance can bite you hard with little or no warning.

 

Well, okay! Back to running badly, like flipping a switch. Not as bad as before, but not good. Then I had to stop and shop a bit on the way home, and it's back to running decently.

Something else is going on, obviously.


I have an on order, so that should help me get to the bottom of this. I'm looking forward to being able to see what's happening in real time, instead of just reading stored codes after the fact.

 

Mark....now I'm in suspense! What's been happening and has everything been resolved?

MrTodd

 

6 year old thread revival..... Pretty sure his Jeep is now totaled.

 

I know. I'm bored and was reading through threads and this one struck me. I always wondered what happened!

MrTodd

 

Well, since you dragged it up out of the moldy grave, I'll fill you in.

It cleared up on it's own. Dunno what that was about.

And yes, it was totaled a few years ago when some idiot in a Suburban pulled out from a side street in front of me.