ICM Issues

[Alchemy333]

Ive been having this issue with what appears to be an intermittent misfire/rough idle... persists to around 4k rpm. New crank and cam sensors, new coils, fuel filter, plugs, wires... tried the ECM replacement (which failed and I had to return), and following the advice in the forum of swapping out the ICM instead.

 

Ordered a Delphi from Partsgeek... wouldn't start. Rechecked everything... ran down to Oriellys and grabbed a MasterPro ICM. Installed and ran super rough and had no power. So, I reinstalled the original I took out... started right up as it was prior to attempting replacement.

 

Is there something I'm not doing right or some sort of setup I may be unaware of? Or, were they just 2 bad ICMs in a row? Or, may this be the sign of a separate problem?

 

PS. Still have the "No E Codes" at scan. 

 

Thanx!

Edited April 15, 2023 by Alchemy333
Correction R code to E code

[Ronnie]

7 minutes ago, Alchemy333 said:

Ordered a Delphi from Partsgeek... wouldn't start. Rechecked everything... ran down to Oriellys and grabbed a MasterPro ICM. Installed and ran super rough and had no power.

It's very unlikely that you got two bad ICMs. Must be a problem with wiring or something. Install one of the new ones and run these tests to see if you can figure out what is going on.

 

Reatta Owners Journal - ICM & Crank Position Sensor Troubleshooting

[2seater]

The best situation would be to swap in a complete operational system from another 1990, including a different Prom. A big ask for sure, but if the tests don’t show anything, the individual parts swapping isn’t working. I don’t remember if I mentioned possible front of engine harness damage, inside the loom. I am not sure if the tests suggested above will reveal that or not? We need to definitely eliminate the ignition through ecm system as the problem. 
 

If it runs well enough to idle you can go through injector overrides to isolate a bad cylinder. How about six spark testers from Harbor Freight. Relatively cheap and gives simultaneous spark quality visual info.

 

 

[Alchemy333]

@2seater oooh... good idea with the spark checkers. I'll knock that off the list tomorrow. And what is the crank sensor light/tester that was mentioned in the ICM tests @Ronnie listed?  I also returned both of the new ICMs already... cuz that was 300bucks out of my budget. Is it ok to perform the tests with the original/working module? 

 

...and who would have a new PROM? I seem to have sought one out with no results a while back. Plus I'm in Cali and need the proper chip for a smog test eventually (we previously determined that is the one I have).

 

I also recall a company that reprograms ECMs for the 3800. Might that be a solid option?🤔

 

Edit: out of all the wiring I have gone through... my clips and insulation appears pretty solid. All the wire protecting sheathing is brittle and breaking of everywhere... which will be replaced once everything else is in order. I checked all my grounds and cleaned the one under the ICM as well. Only loose wires I can't find homes for is near the drivers side fuse box... and one near the ECM.

Edited April 13, 2023 by Alchemy333

[Ronnie]

5 hours ago, Alchemy333 said:

And what is the crank sensor light/tester that was mentioned in the ICM tests @Ronnie listed?  I also returned both of the new ICMs already... cuz that was 300bucks out of my budget. Is it ok to perform the tests with the original/working module? 

Here are instructions for making the test light I used.     Reatta Owners Journal - How To Make A CPS Tester  Some people have found that a digital volt meter would work for doing the test but mine wouldn't. That is the reason I had to make a test light.

 

You can do the tests on the old ICM but the tests were intended to be done on a car that won't start. I was hoping you still had the Delphi ICM to use for the tests.

 

I did the tests on my car when it was running fine just to get a baseline on what the test results should be. You should get the same results I did if you do the test. I don't think it will help with pinpointing  a miss or poor performance if the engine will start and run.

[2seater]

Hopefully we aren't chasing our tail. I think we centered on the ICM-ECM area because of the loss of E data that occurred? For the purpose of eliminating the one part that is common to every test so far, I think any borrowed 1990 Prom could be substituted. It seems that changing various parts does cause a change in operation so...? I think testing for continuity and possibly short circuits in the wiring from the ECM to the ICM may need to be done. It is pretty straightforward since the color codes at both ends are the same. Having a helper would be of great help here

[Padgett]

I always remove the pad in the 14 pin ICM connector. Pins are short and with the single bolt do not always make a good contact/

[Alchemy333]

7 hours ago, Padgett said:

I always remove the pad in the 14 pin ICM connector. Pins are short and with the single bolt do not always make a good contact/

Dang... wish I would have thought of that, although it did cross my mind, before returning both units so impulsively😬

 

The single bolt also has a locking retainer on the inner side, which i made a few attempts to remove, thinking it may have been interfering with a complete connection. Even thought about shaving down the plastic female end of the connection... at which point I'd have possibly lost 150 bucks through experimentation, unable to return tge part.

Edited April 13, 2023 by Alchemy333

[Alchemy333]

15 hours ago, 2seater said:

I think testing for continuity and possibly short circuits in the wiring from the ECM to the ICM may need to be done. It is pretty straightforward since the color codes at both ends are the same. Having a helper would be of great help here

I'll run through the tests in the next day or so here... and report back. Appreciate the support! 

Edited April 14, 2023 by Alchemy333

[DAVES89]

On 4/13/2023 at 12:37 AM, Alchemy333 said:

@2seater oooh... good idea with the spark checkers. I'll knock that off the list tomorrow. And what is the crank sensor light/tester that was mentioned in the ICM tests @Ronnie listed?  I also returned both of the new ICMs already... cuz that was 300bucks out of my budget. Is it ok to perform the tests with the original/working module? 

 

...and who would have a new PROM? I seem to have sought one out with no results a while back. Plus I'm in Cali and need the proper chip for a smog test eventually (we previously determined that is the one I have).

 

I also recall a company that reprograms ECMs for the 3800. Might that be a solid option?🤔

 

Edit: out of all the wiring I have gone through... my clips and insulation appears pretty solid. All the wire protecting sheathing is brittle and breaking of everywhere... which will be replaced once everything else is in order. I checked all my grounds and cleaned the one under the ICM as well. Only loose wires I can't find homes for is near the drivers side fuse box... and one near the ECM.

Don't use that one. I believe that is to power the Bose [shared harness with a Riviera].

[2seater]

17 hours ago, Alchemy333 said:

I'll run through the tests in the next day or so here... and report back. Appreciate the support! 

One thing I forgot to mention about the inexpensive spark checkers: If you have one or more that appear to indicate irregular spark, switch it with another and observe if the problem child follows the spark tester. The way the ignition system works, if you lose one spark plug, the other one of the pair is likely compromised as well.

Edited April 14, 2023 by 2seater

[2seater]

On 4/12/2023 at 9:26 PM, Alchemy333 said:

PS. Still have the "No R Codes" at scan. 

 

 

"R" codes?? You are looking for "e" prefix codes, and "c" or "h" suffix to indicate if active or not.

[Alchemy333]

6 hours ago, 2seater said:

"R" codes?? You are looking for "e" prefix codes, and "c" or "h" suffix to indicate if active or not.

My mistake... I meant E code

I do have b552H, r026H, r034H and r061H

 

I also grabbed another ICM from Advanced Auto and installed it to rule out bad ICM's, and perform tests if it were still necessary. Cranks with no start... just like with the Delphi. To reiterate, it was running with the misfire, prior to this new install... with the reinstalled original ICM.

[DAVES89]

I have to wonder why you are trying to get an answer "over there" when they same guys you are getting help from here are also over there. 

Edited April 15, 2023 by DAVES89

[Alchemy333]

14 minutes ago, DAVES89 said:

I have to wonder why you are trying to get an answer "over there" when they same guys you are getting help from here are also over there. 

I actually posted in the other forum by mistake...😆 I should check if any responses and delete otherwise.

[Ronnie]

58 minutes ago, Alchemy333 said:

I also grabbed another ICM from Advanced Auto and installed it to rule out bad ICM's, and perform tests if it were still necessary. Cranks with no start... just like with the Delphi.

Are you bolting it on to the mounting plate or are you just connecting the wires when you are trying the new one?

[Alchemy333]

3 minutes ago, Ronnie said:

Are you bolting it on to the mounting plate or are you just connecting the wires when you are trying the new one?

Im bolting it down snuggly. 

[Alchemy333]

I just recalled... when I plugged in the new/refurbished ECM (before it failed), it gave the code "No E Data"... which makes more sense as to why I may be having issues. I just went through the process of resetting the ECM... with no change. This is leading me to believe that the swapping of ICM is not being registered by the current/original ECM... and I feel at this point I should lean towards another replacement. What you guys think?

Edited April 15, 2023 by Alchemy333

[Ronnie]

When the engine will not start with the new ICM are the spark plugs getting spark from the coils? That is the first thing you need to know. Next thing you need to know is if the injectors are spraying fuel. Knowing the answer to those questions will give you an idea about where you need to start looking to find out why the engine won't start.

 

If the engine will start with the old ICM and not with the ones, I don't see how the ECM could be the problem. The ECM has no way of knowing which ICM is connected to it. If you do the test properly that I recommended, I'm confident that you will find the problem. 

[Ronnie]

This is just a shot in the dark but something worth checking...

 

The only logical reason I can think of that the engine will start with the old ICM, and not with the new one, is maybe one of the pins in the ICM connector is broken off and sticking in the old ICM. That might allow the broken pin to make a connection with the old ICM plugged in but not with the new one.