coil pack/ignition control module

[Blue90]

I noticed some green goo leaking from the ICM on my '90 vert so I replaced it with a unit I got from a PnP from a '90 Riviera that looked clean.

Now the car won't start.  It cranks but won't catch.  

I'm considering putting the original unit back in to see if the one from the Riviera is bad.

Any ideas would be greatly appreciated. ?

[Cargirl]

I would definitely swap hem out to see if you bought a defective unit, sounds like you did. Question: Why install a used part when that item is available new?

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[Ronnie]

I think Cargirl is probably right. Two things to look for when you take the connector loose from the ICM. Make sure none of the pins got bent (see photo) and check to make sure you didn't use 2 rubber seals between the connector and the ICM. I've heard of someone installing the connector with two rubber seals and it held the connector away from the pins resulting in the engine not starting.

 

[Blue90]

Thanks Ronnie, I will check out the seals and pins.

But I think Cargirl is right, I should just buy new units.

[DAVES89]

A crank sensor can go just like that as well. I parked the Black for the summer and about two months later went to run it for a while and it wouldn't start. Ran when parked and then very next start... no start.

[Blue90]

I don't know why I didn't notice this when I first undid the connection but this doesn't look good.?

[Ronnie]

I have to agree. It doesn't look good. Looks like the two wires at the top of the photo might be touching.

[2seater]

That is ugly. Lots of what appears to be heat damage. The one plus on the '90 is the harness with that connector is a complete sub-harness that should be easily available at the PnP. The harness also connects the cam and crank sensor as well as the knock sensor I believe. The main connector for the sub-harness is behind the power steering pump.

[Blue90]

Thank you 2seater, that is good to hear.  I assumed the harness continued through the firewall.  I will check that out.  I envisioned a long afternoon splicing old, burnt wires together.  

It's difficult to tell from these photos but I cleaned all the exposed wiring with spray degreaser and then a CRC electrical cleaner.  I separated the wires and sprayed with a clear rubber coating called Flex Seal; put everything back together with the original coil pack and ICM, and it still won't start.  I'm too tired to do any more today so tomorrow I will start the quest with fuel and spark, not unlike court and spark.

[2seater]

If any of the wires did indeed short out, it could possibly take out the ICM and as Dave mentioned, the Crank Sensor can fail causing a no start. There are two signals from the crank sensor and if one of them fails while running, it will continue to run but will not restart. The ICM issue could be coincidental, and not the root cause of the no start.

[Blue90]

17 hours ago, 2seater said:

That is ugly. Lots of what appears to be heat damage. The one plus on the '90 is the harness with that connector is a complete sub-harness that should be easily available at the PnP. The harness also connects the cam and crank sensor as well as the knock sensor I believe. The main connector for the sub-harness is behind the power steering pump.

2seater, a '92 Riviera just came into a PnP near me, does it have the same type of sub-harness as the '90 Reatta?

[2seater]

I do not know for certain. That would be a vin L engine but am pretty sure the sensors are the same and in the same locations on the passengers end of the engine. The coil/ICM upgrades we seek are used on the vin L engine so should be compatible. Good time to do the upgrade now and grab all the parts.

[Blue90]

Thank you, I will try to get to the yard today.

[padgett]

Be better off upgrading to the later Delco unit used from '91 up. The complete system is a bolt in replacement. Do need to make sure the wiring and connector are ok.

http://performanceresearch.us/padgett/cars/coils.htm

[Blue90]

So an update:  It's late and I just returned from Hood River where my 99-year old mother-in-law is going into hospice; but it's ok.  She's not in any pain, she's lived a good, if hard, life,  and she still considers me her favorite son-in-law (I'm also her only son-in-law!).  And I'm on my second glass of Burgundy.

Anyway, on Wednesday I spent over two hours at the yard removing the wiring harness from the '92 Riviera.  I couldn't believe how many parts I had to remove to get to this harness; the coil pack and ICM (which I was keeping) , the alternator (which means removing the serpentine belt (which I just cut off, this is a PnP after all)), a couple of hoses, and some brackets; (one around the crankshaft which had 17 mm bolts holding it on, as compared to the same bracket on the Reatta having 10 mm bolts).  And the engine had an oil leak which meant everything was filthy with grimy oil;  to paraphrase the king of Siam, " et cetera, et cetera and so forth).  In other words, a typical day at the yard.  You know it's either cold and wet or hot and dusty.  This day it was hot and dusty.  I had to return Thursday morning to finish up but I got it all. Thank you again 2seater, I'm sure this is the same harness and it cost me $5.  I also picked up the coil pack and ICM, which cost me $50, and the alternator (which I had to remove anyway, and I had checked out at my local FLAPS (O'Reilly's), and it tested good, for $35).

I have not tried to start the 'vert since the wiring is obviously suspect.  I am about to begin the journey of replacing the wiring harness.

I will try to keep you all (I can't believe I said that!) posted but my personal life keeps interfering with my automotive life.  I can't understand how that happens.

[Barney Eaton]

Great follow-up Stanley

[Blue90]

Thank you Barney.  This repair will take me awhile as I will only be able to work on it for a few minutes here and there.  Not they way I like to work but the coil pack one day, alternator another day and soon it will be done.  I take it this is the time to replace the crank sensor also?

[Blue90]

So here we are.  Today is Cinque de Mayo.  My mother-in-law passed away Tuesday night.  Ninety-nine years and three months.  When I saw her Wednesday morning she looked as if she were calmly sleeping.  If this can be said, it was a good death.  And life does go on.

This wiring harness was filthy, so after cleaning it with spray degreaser, I decided to remove the tape and split-loom to clean the wires and install new tape and split-loom.  This is what I found;

Is this incredible or what?  I'm going to repair all these insulation breaks then install this wiring harness in place of the one on the car which has bad wiring.

I tried to research re to R&R the crankshaft position sensor but got poor results.

If someone out there could explain how to do this procedure with the car parked in my carport it would be good.

I did read that removing the passenger front wheel and plastic surround will make access from the side easier than access for the top.  Si?

 

 

[harry yarnell]

OMG! The ONLY way to get to the CPS is thru the wheel well.

[DS_Porter 89 Burgandy]

I have replaced a few CPS's without taking off the wheel. It depends on whether or not your harmonic balancer is a tight fit or a slip fit. You should be able to remove it with your hands after the bolt is removed.

  There is a good trick for loosening the balancer bolt. First remove the vibration dampener and bracket. Put a socket and bar on the balancer bolt and bump the starter. Be sure to unplug the ignition module or the spark plug wires. You may need to put an extension pipe in the socket handle so that it stops against the frame or the floor. Start with the wrench already against the frame or close to it. The engine will turn clockwise which will loosen the bolt.

[harry yarnell]

Last time I replaced a CPS, the replacement was FIXED, not adjustable as before. Best thing since sliced bread!

[2seater]

15 hours ago, Retired w/Reatta said:

So here we are.  Today is Cinque de Mayo.  My mother-in-law passed away Tuesday night.  Ninety-nine years and three months.  When I saw her Wednesday morning she looked as if she were calmly sleeping.  If this can be said, it was a good death.  And life does go on.

This wiring harness was filthy, so after cleaning it with spray degreaser, I decided to remove the tape and split-loom to clean the wires and install new tape and split-loom.  This is what I found;

Is this incredible or what?  I'm going to repair all these insulation breaks then install this wiring harness in place of the one on the car which has bad wiring.

I tried to research re to R&R the crankshaft position sensor but got poor results.

If someone out there could explain how to do this procedure with the car parked in my carport it would be good.

I did read that removing the passenger front wheel and plastic surround will make access from the side easier than access for the top.  Si?

 

 

If I understand correctly, this is the replacement harness? It looks like the insulation breaks are only on the crank sensor portion unless there are others I cannot see. Was there any external indication, such as melted loom? Scary

[Ronnie]

I saw something similar once. The battery was cracked. Water/acid was getting into the loom that ran beside the battery and was running down through it to the lowest point in the loom. The acid didn't bother the material the loom was made of but it attacked the insulation on the wires.  I caught it before the insulation came off but it was brittle, cracked and discolored. 

 

The wires that were saturated with the acid went to the hall effect sensor in the distributor (Chevy Cavalier). It was keeping the car from starting. I was tracing that circuit which lead me to take the loom apart and find the damaged wires. Battery acid will conduct electricity and short out wires once it attacks the insulation... even if the conductors in the wires aren't touching each other.  That is what was happening on the Cavalier.  Is the insulation on those wires in the photo discolored?

[2seater]

I suppose it depends on how the harness was routed but I think my CPS harness goes between the lower radiator hose connection and the block, sort of pinched in there. Looking more closely at the previous pic of the replacement harness doesn't appear to have an external indication of the broken insulation. Time to look at the harness on the engine I have on the stand.

[Blue90]

Yes, this is the replacement harness from the '92 Riviera.  The looms were not in bad shape, no meltdowns; I only removed them to clean out the gunk that had accumulated inside.  This was the only section of wire that was bad.  The insulation on the broken wires is discolored and you can see some pitting/burning on them as well.

Harry, would you please explain fixed vs adjustable?

Is DS_Porter 89 Burgundy's method the way to go?

[DS_Porter 89 Burgandy]

I believe fixed vs adjustable refers to the Crank Position Sensor being tightened with the mounting clamp and adjustable as opposed to a fixed style which I have not had the fortune to see. The adjustable type needs to be carefully adjusted so that the gapped rings on the back of the harmonic balancer have clearance inside the CPS coils.

[harry yarnell]

The factory and the early aftermarket CPS's were mounted on a bracket that the sensor could slide on so that when mounted  (the whole assy), on the engine , the shutter blades on the balancer pulley would align up perfectly in the slots of the CPS. Once aligned , a screw clamped the sensor and bracket together.

The last one I installed was one solid piece; no fiddling with shims to get the gap right. Apparently somebody got the bright idea that no adjustment was necessary.

[Blue90]

23 hours ago, DS_Porter 89 Burgandy said:

I believe fixed vs adjustable refers to the Crank Position Sensor being tightened with the mounting clamp and adjustable as opposed to a fixed style which I have not had the fortune to see. The adjustable type needs to be carefully adjusted so that the gapped rings on the back of the harmonic balancer have clearance inside the CPS coils.

 

17 hours ago, harry yarnell said:

The factory and the early aftermarket CPS's were mounted on a bracket that the sensor could slide on so that when mounted  (the whole assy), on the engine , the shutter blades on the balancer pulley would align up perfectly in the slots of the CPS. Once aligned , a screw clamped the sensor and bracket together.

The last one I installed was one solid piece; no fiddling with shims to get the gap right. Apparently somebody got the bright idea that no adjustment was necessary.

 

Thank you both for the explanations.