thoreightysix

Car died randomly the other day. It started back up for an instance, died again. It wouldn't start. Waited for a little while, started back up again. I let it idle for a few minutes, then it died again...no sputter, just cut out. I had to wait even longer for it to start. It started and was able to drive home a few blocks ( just drove it conservatively). I started it the next day. Started just as good as ever. Began my investigation, and believed it to be the ICM from all the studying of threads on here over the years. I took it to 2 Oreilly's locations, one tested it bad, one tested it good. I am torn between this ICM and the Opti.

I can't scan for codes because I believe that the previous owner didn't hook the ALDL data port up correctly ( 93 car with 94 computer / MAF).

This ICM module is definitely an old stocker, so I'm thinking that it probably doesn't have much life left anyways. When i took it off the heat sink, the backside looked nasty as well as the heat sink with no signs of old thermal paste.

bad coil? opti? ICM? ICM harness?

Any help would be greatly appreciated as always. In a tough spot, or I would of already replaced the ICM.

shoebox

Getting it scan capable would help. Otherwise you have to guess. Anything electrical is subject to odd behavior. The "no thermal paste" would be a bad sign, though.

thoreightysix

Thanks for responding!

The coil is newer, opti is a few years old.

As far as the data connector, i am quite intimidated when it comes to tackling it. I do have the USB adapter for my laptop though...

The weird thing is that it started after the car sat for a while. Got fired, it sat for about a week, then acted up when I left the store Saturday.

The car has 152xxx, so that ICM has probably seen its share of heat cycles and will be going out in the near future. Probably start with replacing it and installing it properly with my fingers crossed ( the opti would sink me).

From my reading on here, the ICM is a common issue, right?

Thanks Again

thoreightysix

Alright. I replaced the ICM, used an AC Delco unit. Started it up, let the car get as close to operating temperature as possible. Upon revving the engine, I killed it. Wouldn't start up right away...waited a couple minutes, started and ran for around 40 seconds then died.

I'm thinking it's the opti, optical cam position sensor perhaps? There is a tiny oil leak in that are and didn't replace the seals the last time I was in there, so oil might of made it's way inside.

Of course I need to get it scan capable, where would I start on a 93 wiring theto a 94 computer? Any tips? I have the DLC_wiring, just wondering if there is anything else I should know.

Injuneer

93 and 94 both use the same 12-pin data link connector. Use the wiring diagram for the 94. Shoebox has the wiring for all years on his,website.

thoreightysix

Checked out the wiring situation. The tan wire (D30), wasn't connected on the PCM side and the ALDL side :I. Connected the wire, still cannot see the PCM. There was another wire that wasn't connected, D9, a black and white wire that goes into the same plug as D30.

I guess the next step is to buy some wire and run a new D30? I am lost and without proper equipment.

Injuneer

What scanner are you using? You can't short the pins on a 94 and flash the codes on the SES light. 93 was the last year that worked.

thoreightysix

Im using OBD1 to USB hooked to my laptop, using TTS datamaster. I had success connecting to it. I ran a new tan, serial data wire from ALDL connector to the PCM. Quite a timely process, killed my battery at 31684 bytes received. I'll have to jump it tomorrow and finish scanning, find out what's wrong with this beast.

thoreightysix

Ok. I jumped the car ran it for a while to charge the battery. Started freescan, let it scan for a long time, a very long time. Did not throw any codes, but it did gather the cars info. Does freescan give you indication that the scan is complete? Or does it just keep gathering bytes? I'm surprised I didn't throw any emission codes. My cat is supposed to be 'gutted' ( according to the previous owner).

I started the car to keep my battery alive, monitoring the freescan dashboard. Got the car as hot as possible, revved it up. Did not die. Before, while it was hot and I revved it, it would die. That wasn't the only screwy-part. It started right up, again and again! Hot. Hotter than it has been since it was running right.

The only possibility I can think of ( at least until I get a multimeter), is that oil got into the opti. Maybe there was oil on the optical disc and the oil broke down from getting the car hot enough. There is a small leak in that general area. The problem did start when I stopped driving it everyday. I am baffled. I was hoping for a code for some direction.

Injuneer

Codes are set by diagnostic routines. Some of the routines are not run when the car is sitting and idling. If the emissions have been deleted, maybe they have been deleted in the tune, preventing codes from being set. If the battery was disconnected at any point, or just died, you would have lost ll the stored codes. In a 93, there is no after-cat O2 sensor to determine if the cat is there and working. You would not get a code for a deleted cat.

I don't use DataMaster for logging (I don't use the stock PCM to run the engine), I just use it to review data logs for people. I suspect it will just keep running until it reaches the limit of storage capacity. There is no "complete"..... it's just recording data. There is no set routine that it has to go through.

thoreightysix

So, am I going to have to drive it around to throw the code?

I do have the log, but the formatting looks all funky ( using Open Office).

Injuneer

Depends on the code. Some will set when the engine is cranking (example - cam position sensor), others have to be on the road (example - EGR).

With regard to the formatting, are you using the 93 or 94/95 version of DataMaster?

thoreightysix

I was using the 94, F-Car w/ auto trans.

thoreightysix

Ran freescan & TTS datmaster, got the car to stall ( upon revving ), no codes. This sucks.

Injuneer

Have you checked the fuel pressure?