Injuneer

If the bolt isn't long enough to accommodate the three washers, get a longer bolt. Make sure it is long enough to add the three washers behind the ICM bracket, and to hold the ground straps in front of the ICM bracket, with the washer to minimize twisting of the strap lugs when you tighten the bolt. I would go as far as making one of the 3 washers a fiber washer, rather than metal, to minimize heat transfer through the washers.

Rob/Shoebox mentions that the 93's use a bolt rather than the stud. Your 94 may be a very early production model that carried over the bolts from 93.

As far as the MAF - you made two changes at once - cold ICM and no MAF. You really don't know which change made it idle better. Reinstall the intake duct and MAF, making sure there are no tears in the rubber elbow, and that the elbow fits fully over the throttle body, particularly on the bottom.

16Sammy61

I imagine this 94 must be right at a awful point for changes. If its an early production and carried over the bolt, i was informed on Shoebox's website that i have the dual fan config.(3 relay system) from late model 94's. This car has the potential to run amazing, but i run into countless problems. Just now as i was removing the inboard nut, it merely pulled the stud out with it because it is so rusted on. You wouldnt happen to have the appropiate stud length so i could install one?( might just install 2 to make my job easier) the one that came out is about 1 3/4" long. I tested it with the EVAP hose bracket and 2 3/8" washers and the coil bracket on the stud. It looks as if there will be enough room for the outside nut to hold it on. JW if its easier to install a outboard stud the same length or get a longer bolt.

16Sammy61

Scratch that, i bought a longer bolt and gapped the icm out. Its about the inch it should be and everything is plugged up. It still died three times on me but it started back up within 5 minutes each time. Now its running terribly hot it was at the 260 mark when i was rushing to get it home. There was coolant exploding out of the recovery tank and i had to catch it. Not sure whats happening now...

Either way i shall have to wait almost another month to be able to scan the car. It tells me the cable is currently in transit from Illinois. It said it left there 6 days ago, however will not arrive until June 23... I dont see how it takes 30 days to get to me in TN, thats only about a 8 hr drive but oh well. The car still died 3 times so not sure if the icm mod worked, however it wasnt nearly as hot to the touch after driving the car. Last time i could barely hold it with a towel. Im at the mercy of the mailing system currently, so the car shall sit until then.

16Sammy61

Friend wanted to come out and check stuff today to put his own input in. It started fine after the usual 2 or 3 seconds of turning. He noticed that when he shut it off and went to restart it right away, the car did nothing. No noises or turning or anything. It had never done that to me until today. He took the key out and let it sit for a minute or two while he did something, come back and it started. After letting it warm up it did eventually just die out of nowhere. He said he thought that when he turned the key back the fuel pump was not making any noise. He thinks the crank sensor could be a problem. Not exactly sure about what he said, but it related to it not getting the right signals. Keep in mind, he works at a Toyota place, but has knowledge over all platforms. His wife has a 4th gen mustang, and his daily drivers consist of a 5 spd Plymouth laser and a dodge dakota v8. Hes not very biased when it comes to brands or types of cars. Although i failed to tell him what would be the CPS(crankshaft position sensor) is part of the opti, right? So would that be a bad, or soon to fail opti?

Injuneer

Your 94 does NOT have a crank sensor, so I can assure you with absolute certainty it is not the cause of the problem.

It does have a camshaft position sensor, and that is the optical module in the Opti distributor. If it has a problem, it should set codes - DTC 16 and/or DTC 36. And that is one of the items we have already discussed as a possible source of a heat soak problem. That's why somehow, you have to scan it for codes.

Did you ever get around to checking the fuel pressure?

16Sammy61

As of now, i wont be scanning it any time soon. Recieved one part of my cable today and its not even the right thing. Already sent the seller a very...descriptive message. Basically i want my CORRECT cable within a week or action will be taken.

Still trying to find somewhere that will test my pressure, or let me borrow one. Have been busy last day or two, and haven't got around to find one. Theres an autozone a town over, just too busy to make my way there and back in one day. Might be able to tomorrow depending on schedule.

Letting the car sit for now, sometimes let it run for 2-3 minutes just to keep it alive and well. Will check back in ASAP or when i get the pressure checked.

maybe2fast

260* !!!! Start with a hydrocarbon test!

16Sammy61

Im reviving this thread! I finally got my car scanned and can now let you guys know everything.

First, the overheating is probably not fixed. The radiator has been looked at and it is somewhat clogged and dirty. I can pay someone $80 to flush it, but can i do it myself? I have a hose, so if someone can tell me a good way to do it then let me know.

Second, i have now scanned the car. After 2-3 seconds of turning it started. At first it held at 2k rpms for about 2 seconds. Then it dropped to idle. The idle was a little rougher than usual i thought. No DTCs yet. The car idled for a few minutes im not sure how many, but i gave it a few small revs here and there. Eventually it just cut off with no warning signs or anything. Right then and there two DTCs were set(they will be posted below). I went to start it again and it took a little bit this time but it did start again. This time another DTC became present. I let the car idle some more before i stopped the scan and cut it off. Near the end i gave it some higher revs in an attempt to see if it would throw another code, but there was nothing. Keep in mind the engine never got close to temp. I dont really want to run it anywhere near hot or warm.

Third, the reason imdont want to run it hot or warm is because of the head gaskets.There arent any major symptons of the failure but i have a feeling they may be going bad anyway.

Finally, the DTCs. When the car cut off for no reason, it set DTC 41 and 42. It said something about icm but im not sure exactly what it means. The other DTC is 36. I know it has to do with the distributor, but again im not sure what it means. Whatever info about them you guys have to offer will help.

Also, i noticed it said the fan relays were both working, or sending signal or something. I know its because the SES lamp was on, i learned about my fan system on Shoebox's website. I know only the passenger side fan comes on, so does it mean the driver side is broke or wore out?

Every little bit of information you guys have to offer will help me. Im unsure about everything at this point.

SA68SS

30 dollars will get you a new coil, and this was the problem with my car last week. One symptom that I had every time just before it died was the tacho jumping high.

When it died I would try to restart, with spluttering results, and then after a cool down it would start and run.

If you are going toward an engine rebuild, a coil would be a cheap attempt at a fix.

16Sammy61

I know a coil can be had for 30, but the code is about the icm. Which is around 90. Not sure yet anyway, however i have no signs or anything to tell me the car is going to die. It idles for awhile and it just cuts, like you turned the key off when you were done driving. So im not exactly sure.

I do not think the whole engine needs a rebuild. I have not yet confirmed the head gaskets are going bad, im just guessing. i can do them myself for the cost of gaskets, new head bolts, and some sealant. Thats assuming the heads arent warped either, which they shouldnt be.

16Sammy61

I also have the data log if anyone needs it! It is saved as an excel file from Scan94/95 but if it needs to be changed to something else it can be done.

16Sammy61

Any help? Not sure what the codes are telling me. Does it mean new opti and icm, or is there a different problem? Any input is greatly appreciated!

moparman

You're right about the DTC 36, problem with the opti. Both 41 and 42 could have something to do with the ICM. Also check the opti wiring and wiring for the ICM.

I don't have an OBDI car, so I'm just going by what I've read on some diagnostic sites.

16Sammy61

This is my first OBDI car. And, i also, am just going by what i have read. I think i should try to change the opti harness first and see if that fixes it. But im not sure how to check it. I just need more in depth info to know if i should just change the opti completely.

Definitely am going to change the coil, icm, and the wires for it because it looks awful. However, if i do that, i would like to know if i should just do the opti, plugs, wires at the same time since im there.

Injuneer

DTC 36 (OBD-2 equivalent = P0372) indicates a problem with the high resolution pulse signal from the optical cam position sensor in the Opti. That code should not prevent the engine from starting or running. When the PCM loses the high resolution signal, which is uses for extremely high accuracy spark and injector timing, it defaults to the low resolution pulse. If there was a problem with the low resolution pulse signal, you would have DTC 16, and that does prevent the engine from running or starting.

The harness problems are generally due to corrosion of the harness connector pins, damage to the pins, or loss of insulation on the wires. The "short" Opti harness starts at the gray 4-pin connector on the EVAP bracket on the passenger side of the intake manifold, and runs to the rear portion of the Opti body. Both ends of the harness should be examined for damage.

The no-start is most likely due to a problem with the ICM. DTC 41 and DTC 42 sort of contradict each other, and may point to a wiring problem at the ICM/coil connector interface, or an internal problem with the ICM

DTC 41 = Ignition Control (IC) circuit (open circuit)

DTC 42 = Ignition Control (IC) circuit (shorted or grounded circuit)

http://shbox.com/1/Dtcs.htm

The best thing t do would be to get hold of the factory manual diagnostic charts for the two codes, and work your way through them. Alternatively, take the ICM to an auto parts store and have them test it. Make sure they get it good and hot while testing it.

Here is a link to a post on another site that has a free download of the 1994 (and other years) factory manual.

LINK: 4TH GEN SERVICE MANUALS; 82-02 PARTS DIAG; 99-02 WIRING DIAG - Firebird Nation