I've got a few ideas, but...here are a few questions first.

Where did the replacement dizzy come from? What year?

What does the Crank Angle Sensor in the dizzy look like. How many holes are there near the center?

Talk a bit more about the damaged crank pully. If the keyway is wallowed out that much it really should have been replaced. But, that damage is probably not causing the issue, just something for the future.

What does the exhaust smell like at idle? (If you can smell it at highway speed, I'll send you a cookie. <img src="/forums/images/graemlins/smile.gif" alt="" />) With this much gas, it should smell very very bad. If it doesn't then this is a vacuum issue, not fuel. (Or even lack of fuel) Either one will create obscene EGTs.

Just a few ideas...

Michael

Man, don't tell me they changed THAT in '93, too?

From what I can recall the internals are identical. The ring and the sensor are very similar, if not identical. They both have the two locator holes, and then hole with the flat in the center, and of course the 360 little tiny slots. I will go to the salvage yard and see what year the Trooper is I got the dizzy from. I will also call my friend and see what year his is.
The damaged pulley/damper, I replaced. My old damper/pulley was trashed (wallowed keyway being the main problem), results of the loose bolt. Oddly enough, the crank escaped with only some minor scuffs and no real damage. I only had to remove a small burr on the end to get the new damper in place.
Strangely enough, the exhaust really does not seem particularly pungent. I have run it in the garage a number of times while working on this, and it seems to smell normal. But, that is without load on the engine. Without load on the engine, that gives me an idea, it does this with load on the engine, maybe it is a vacuum problem?? Maybe it is fuel pressure regulator related?? Even on the short drive, the hill to my house lit it up, and that hill is plenty of load, that is for sure! I wish it was an auto, it would be much easier for me to simulate a load on the engine (power brake it). I am going to pull it in the garage and give it one last hurrah before I throw in the towel.
There is actually an Amigo on Ebay I have been watching. It looks pretty good, and so far has stayed fairly low in price, but then we all know what happens on Ebay in the last 5 minutes of an auction.

Man, don't tell me they changed THAT in '93, too?

Batch fire to SEFI.

Michael

So it finally threw a code, code 61, which indicates a short in the air sensor circuit. I checked the air sensor, and the wires form the MAF to the ECM. All check okay. At least the wires do. I don't know what the values should be on the MAF, but it has continuity. When I tried to ohm it out, I actually could not get a reading on any of the resistance settings, but it did show that it has continuity. Not being too much of an electrical type, I don't know what this means, it probably just means I have a crappy multi-meter (paid $3 at Harbor Freight), but I am not sure. I actually pulled the top off of the MAF and there was some corrosion between the actual sensor and the base, where it mounts. I cleaned this up, but have not driven it again. I will test drive tomorrow and see what happens. I really can't see anything else wrong. While talking to Michael on the phone, I checked the EGR, mostly just to eliminate it from the equation, and it seems to be functioning. I am beating my head against the wall on this one, and really don't know what is causing the red hot manifold???! And I just missed a great deal on a '98 amigo. I told myself my max bid would be $3995, and the stinkin thing went for $3850!! I was in the garage swearing at the Trooper when the auction ended (forgot it was ending and didn't go bid). I blame the Trooper<img src="/forums/images/graemlins/evil.gif" alt="" />. Now the cloud of profanity that hangs in the garage will grow a little darker! <img src="/forums/images/graemlins/angry.gif" alt="" />

All right, I'll clarify a few things from above. 1. I learned that what I thought was for continuity (on the multimeter), is actually for checking diodes (not too much of an electrical guy, got a C in EE210). So, this tells me the readings I was getting, say there would be an extremely high voltage drop across the MAF sensor. This is probably not the case, I doubt the wires in the MAF are diodes (not impossible, but maybe improbable). I say this, because the value I get when I check them indicates there would be a 1600 volt drop across the MAF, on one wire, and an 800 volt drop on the other. I don't think this is the case. That being said, I think the code thrown, may actually be the problem. If I have an open short in the MAF, this could drastically affect the mixture of the engine, possibly causing the glowing red manifold. Why it took so long to present the code, I don't know. Maybe it just wanted to be sure it was really dead before it threw a code. Also, the CE light never has come on, I was checking codes out of desparation. I did check the resistance on the MAF, and one side appears open, and I believe it is the hot side, at least it is the side with the wire with the red stripe (the code indicated there is an open short on the hot wire of the MAF). I am going to pick up a MAF at the salvage yard tomorrow. Hopefully it helps.

BTT, in case anyone who might know something has not seen it yet. I got the salvage yard MAF, looks to the same as the old, at least that is what the multimeter tells me. I am going to put it in, just for kicks, but I think the results will be the same. If anyone has any ideas, I would be glad to hear them.

2/17/05
Ran a few more tests, at the suggestion of Jerry Lemond. Checked the vacuum, it holds 15 inches at idle, and does it steadily with the timing set to specs, I can get it up to 17 inches if I advance the timing. Doesn't seem to be a vacuum problem, or a burned valve problem, or a misfire problem. I have test driven with timing advanced, and with the timing set to specs, both cause the manifold to glow. At this point, I am suspecting a clog in the exhaust again, somewhere upstream of the cat, farther upstream than the muffler shop tested. Maybe at the flex pipe I installed. I am going to disassemble the exhaust next and see if I can find any type of constriction or blockage.

I am going to throw this back to the top again. It looks like a computer problem after all. Last I night I disassembled the exhaust, no obstructions whatsoever. Tonight I pulled the intake apart, and cleaned out the common chamber. The EGR tube that exits at the bottom of the opening by the throttle body was totally clogged. I cleaned up all the EGR passages and the throttle body. After I reassembled everything, I checked the timing. At idle, it was right on. I revved it a couple of times with the light still on, no advance. Now in the past, I have seen it advance, but not this time. Even during this whole problem I have seen it advance. Apparently there is an intermittent problem somewhere. So here is my question for the Isuzu gurus; what controls the timing advance? Is it the computer alone, or could there be some other failed component causing this problem? After a test drive, the bogging is back, the hesitation after shifting is back. If it is a bad distributor, would it run at all? Is it possible, the computer is not getting the right signal, and not advancing the timing?

"ELECTRONIC SPARK ADVANCE (ISUZU I--TEC SYSTEM)

Amigo, Impulse, Pickup, and Trooper II 2.6L

The ECM uses inputs from the crank angle sensor to control the distributor advance curve. The ECM is part of the Isuzu I-TEC engine control system. Other sensor inputs to the ECM which control ignition timing advance are as follows:

coolant temperature sensor, vehicle speed sensor, airflow sensor, throttle valve switch and detonation (knock) sensor."

An excerpt right out of my Mitchell's Isuzu Manual-on-CD.

So, the above areas of input to the ECM would be where to concentrate your troubleshooting efforts. And ultimately, it could even be the ECM, but you'd want to rule out the other things first.

BTW I don't recall the 2.6 having a knock sensor, that's probably a 'blanket' description and I'd hazard a guess that the Impulse Turbo is the one with that sensor.

HTH and G'luck........ed

Michael, I want my cookie. <img src="/forums/images/graemlins/wink.gif" alt="" /> The aerodynamics of the Trooper (did I just say those two words in the same sentence?) will cause the air around the back doors to be very turbulent and actually kick into the back of the truck. If you prop the back doors open and go for a ride, you will most certainly smell the exhaust, at any speed. With the doors open (and the front windows) you'll get a cross-ventilation effect where the exhaust will go in through the back doors, right up through the passenger compartment, past the driver's nose, and back out the driver's window. I've personally experienced exhaust smells using this method that made my eyes water they were so rich. <img src="/forums/images/graemlins/wink.gif" alt="" />

Are your cookies any good? Maybe I'll just wait til the next time I see you in Moab to get it...

By the way, Jeepfiend -- AutoZone has a sign on their window where they advertise free code-scanning for your CEL... The sign also says they can test all kinds of things --alternators, batteries, this, that, the other... Including ECM's. Dunno if it'll show your problem, but it might be worth stopping over there...

-Chris

I am heading the salvage yard today for an ECM. I have tested the ditributor, and it seems to be functioning properly. I took it out, hooked it to the battery and then spun it with a drill, while I checked the output of the encoders, and it looks to be functioning. I don't know the specific output specifications, but there was a voltage increase with RPM's on the signal lead, and the injector pulse is coming through strong. It appears to behave properly for an optical encoder.
The problem would be getting it to Autozone to have it checked. I am 40 miles from the nearest Autozone, and 5 miles of driving the Trooper makes the manifold bright red. Personally, I really don't want it to burn, at least not while I am in it. I might call them and see if they can plug it in. I don't know that their machine could tell anything more than having the computer blink codes. From the self diagnostic, the Trooper thinks there is nothing wrong with itself.
I think I have it narrowed to the ECM, but not for sure. I can't think of anything else that would cause it to not advance the timing without at least throwing a code. I would think that if any of the other sensors had a fault that would prevent spark advance, there would be a code for that part. I did have the MAF code, but it has not returned, and the other MAF I got tested exactly the same as mine. Could they both be bad, maybe, but I doubt it.
By the way, the exhaust smells normal at idle, and is rank at higher rpm's. With no spark advance it gets pretty stinking rich above 1200 rpm.