Thier machine (code reader) can tell you lots of things. For example. When the O2 sensor went out on the amigo, he plugged it in while the truck ran. The code reader gave us what the O2 was telling the computer. The 02 sensor didnt go out completely, it just got weaker, thus sending a weak signal to the ecm. Even if something isnt wrong (that the ecm knows about) their code reader can tell you if a sensor is giving the right amount of info (volts) for the ecm to use. Understand?

kevan

Yeah, I'm pretty sure AutoZone can tell you more than just the codes, but I'm not sure that would be a free service. <img src="/forums/images/graemlins/rolleyes.gif" alt="" /> At any rate, since it looks like you've narrowed it down to the ECM (at least, it's worth delving into it more anyway) it might be your easiest bet to replace your ECM with a known good one just to test it.

That being said, the easiest way to get a known good one in there is for someone on this board who's relatively near you to let you borrow theirs... Any volunteers?

-Chris

Didn't know that Autozone had that kind of diagnostic capability. I figured they just had a generic code reader. Thanks for the heads up. I have never been too keen on places like Autozone or Checker for anything besides basics. I have always found their parts to be of lesser quality. They are great for fluids and light bulbs, but I would not buy anything of importance from them. I was feeling cheap when the alternator on my Land Rover died, and bought an Autozone reman'd unit, and the bearings went out in 200 miles. Typically their lifetime guarantee, just guarantees a lifetime of replacing the part.
Since I already have the junkyard ECM I will give it a shot (didn't see your post until after lunch). If it doesn't pan out I guess I will have to figure out a way to get the Trooper to the valley, to an Autozone.

Hey jeep i dont if this helps but im havin the same prob my manifold is glowin red on my rodeo after i drive it. So I told a friend of mine thats a Auto tech he told me its prob my fuel regulator its running rich that makes sens because I keep fail emmisons for HC raw fuel not being burnt. I dont know if this helps you but im gona try that first let me knoe if you find a salotion thanx Ron

I am sure my regulator could be bad, but my timing is not advancing, and I think that is a larger problem. It is definitely rich, but I think mine is more timing related than fuel. All my plugs are dark and the manifold is red hot in only a few miles. But with no spark advance, I am sure that unburned, or burning fuel is being dumped into the exhaust.
The computer was not the smoking gun I was hoping for. It acts exactly the same as it did with the other computer. I guess I will pay the 20% restock fee and take it back. I am at a total loss as to the cause. I will see what Autozone can diagnose. Frankly, the car is not worth taking it to a mechanic. Only a couple of hours with a mechanic, and I would easily exceed the value of the Trooper in labor costs. If Autozone can't diagnose this, I think the Trooper is bound for the scrap yard. I hate to do it, because I think it has a few miles left in it, but it just not safe to drive around with a red hot manifold. From the color, I would estimate the EGT's are probably somewhere around 1100-1200F. That is just too hot to have under the hood, it is not worth the risk of fire. If you have a glowing manifold, I would not recommend driving the car until it is fixed. If it is glowing, it will even ignite spilled or leaking oil. I will see what Autozone can do, but I am skeptical of their capabilities.

Well, you can turn it into a barbequer <img src="/forums/images/graemlins/smile.gif" alt="" /> take it out, open the hood, put a grill down, and start cookin

kevan

That's not a bad idea, with a hand throttle, I'll bet that thing would be red in short order, and I can mount the grill right above the manifold. If I pull the heat shield off and make some other sheids that will help divert the heat to the grill. Then I can cut the back off, and build a smoker on there. It will be the ultimate tailgate party Trooper. I'll just have to be sure to always carry plenty of brauts in cause it really goes up. It would be wasteful to not use a good fire! <img src="/forums/images/graemlins/notooth.gif" alt="" />

BTW, I have called several Autozones, and none of them have the capability to check the ECM and the sensors on an '88. I don't want to be one to say I told you so, but my skepticism was not unfounded. Unless you have a rather expensive tool you are limited in what you can do with an OBDI system. I have looked on line and cannot find any readily available software for OBDI. I am not saying it is not available, I just didn't see any in the searches I did. OBDII is a different story. OBDII scan tools are relatively inexpensive, and the whole OBDII system is considerably more robust. There is a lot more available info from OBDII systems. I have an old laptop with some OBDII software I use on my Land Rover. I don't know what Autozone you went to, but none of them in Utah Valley have the ability to do anything beyond reading codes on an OBDI system, and I have a blinking CEL that will tell me the exact same things. Also, the '93 computer is a bit more advanced than the '88. There were some pretty big changes in '92-'93 on the Isuzu MPI systems, at least on the 4 cylinders. If there is an autozone in Salt Lake that can do the '88 I will take it to them, but none of them in Utah valley can do anything with it besides reading codes.

In reply to original poster>

You keep saying "it isn't worth fixing" - perhaps - but what I ask is what are you going to do if you don't fix it?
Unless you're NOT going to get another vehicle, keeping it IS a cheap alternative. <img src="/forums/images/graemlins/zombie.gif" alt="" /> Any other vehicle will still cost you as well.

I'm having problems similar to yours. My Troop is a 1990 which has had all the common 4ze1 2.6L problems. We bought a new AMC head, complete w. valves. Mechanic had the old head checked because everything looked perfect even though the compression check said trouble. The old head was shaved, and now................after we have returned the new AMC head........the mechanic and my husband both thought the Troop sounded as though there was a valve leaking SO the mechanic took it apart again and there is an exhaust valve leak..[only one].......so the Troop is still in the shop. But he's conscientious and felt responsible for not having discerned the problem earlier, anyway, we're keeping the Trooper, at this point we'd lose too much money if we gave up!

Maybe you could get away from the prob for a few days and come back with a fresher perspective??

Hang in there, I think you'll come up the solution; right now you are just too close to the problem.

Ahem....been there, done that.
<img src="/forums/images/graemlins/cyclops.gif" alt="" />