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 Writeup: Ignition Control Module (ICM) harness repair

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jeffyd123
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Name : Jeff Del Vechio
Joined : 2010-03-15
Post Count : 108
Merit : 4

Writeup: Ignition Control Module (ICM) harness repair Empty
PostSubject: Writeup: Ignition Control Module (ICM) harness repair   Writeup: Ignition Control Module (ICM) harness repair EmptySun Jun 20, 2010 10:40 pm

Procedures covered in this Write up:
-harmonic balancer removal/ installation
-cam and crank sensor replacement
-ICM harness removal, repair (splicing) and installation
-The engine harness was removed from my car but is not covered in this write up.

All work was performed on a 95, series 1 riv with SC.
---------------------------------------------------------------------------------------------------

Well after an exhaustive (and expensive) couple of weekends under my greasy, filthy 95,Series I riv, I FINALLY got it running.

This repair was due to ignition and cam sensor codes being thrown and the car cutting out and/or stalling.

The symptoms were as follows:
car started out by cutting out for a split-second while lugging up hills in OD.
progressed to lots of cutting out and loss of power
car always started and ran fine when cold, problems were after it was warmed up and running

the primary codes I was getting were:
P0321 - Ignition/Distributor Engine Speed Input Circuit Range/Performance
P0341 - Camshaft Position Sensor Circuit Range/Performance
P0361 - Ignition System Problem, Electric Spark Timing, EST Not Toggling

After much reading I had decided to take a look at my wiring... focusing on the ICM harness. The harness starts at the ICM and terminates with an 8-pin plug that attaches to the main engine harness just behind the passenger side of the SC. it branches near the ICM and goes to the Crank Sensor (CKP) and branches again closer to the 8 pin plug and goes to the cam sensor (CMP).

After a little digging in the highly corroded protective sheathing, I had seen that someone had been fiddling around in there.... the dreaded duct tape was present.

I had decided to replace this harness and if necessary, replace the entire engine harness. I ordered the used parts from Morad parts in Ohio. Unfortunately, Morad didnt tell me that they dont include the badly needed ICM harness. this is because it is basically impossible to get out without taking all of the power steering/alternator brackets off the car which is a major PITA. They also clipped off the knock sensor clip so beware if you order a harness.... for $150 I expected a full harness.

I also replaced the cam and crank sensors to be sure I could eliminate the problem.

The following write-up details this repair..

you will need the following:
40 feet 18 gauge wire
about 25 18-22 gauge heatshink, inline crimp-on connectors (autozone has them)
3M brand electric tape 1 roll maybe 2
corrugated wire conduit (autozone) 1" size - 10 feet
good wire strippers ( I got the kind that automatically strip the wire when you squeeze them - Like these http://www.amazon.com/Unknown-STRIPPER-WIRE-AUTOMATIC/dp/B000KT791Y
a crimp tool
2 wood clamps or a vice and a clamp
a bench to work on with good light
magnifying glasses if needed
a cam sensor
a crank sensor
a 3 bolt wheel puller - for pulling the harmonic balancer with 3 1/2" long 1/4" fine thread bolts (I think)
a seal for the harmonic balancer - if needed
grey silicone sealant


lets do this...


Last edited by jeffyd123 on Mon Jun 21, 2010 9:40 pm; edited 2 times in total
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jeffyd123
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Name : Jeff Del Vechio
Joined : 2010-03-15
Post Count : 108
Merit : 4

Writeup: Ignition Control Module (ICM) harness repair Empty
PostSubject: Re: Writeup: Ignition Control Module (ICM) harness repair   Writeup: Ignition Control Module (ICM) harness repair EmptySun Jun 20, 2010 11:37 pm

OK...start by getting the car jacked up so you can get all the way under the motor. you will need to pull the passenger side wheel and the inner fender skirt. when pulling the fasteners for the skirt, pull on the center plastic "knob", it will pop out and then you can remove the fastener.

Uploaded with ImageShack.us[/img][img]Writeup: Ignition Control Module (ICM) harness repair Fenderremoval


unhook the battery
remove the belts... the tensioner bolts are15 mm i think

[img]Writeup: Ignition Control Module (ICM) harness repair Beltsf


now for the horror...removing the harmonic balancer... actually its not that bad when you dont do it like i tried to for an hour.

you will need to crawl under the car and remove the plastic cover that covers the starter ring gear... it has 2 bolts and slides down when the bolts are removed.



viola! the starter ring gear. now put a heavy duty ratchet on the big bolt on the harmonic balancer (13/16" i think) and slowly rotate the motor until you can see a bolt that goes through the starter gear (its what attaches the flywheel to the torque converter. I couldnt get my camera to get a shot of the bolts but they are there.

Writeup: Ignition Control Module (ICM) harness repair StarterringgearWriteup: Ignition Control Module (ICM) harness repair Balancerremoval

OK so when the bolt appears, put a strong pair of vice grips on the bolt and clamp it on there real tight., you will be rotating the engine so the vice-grips will contact the tranny housing at the front of the car. there will be a lot of torque so this needs to hold fast. you can also have a friend loosent he harmonic balancer bolt while you hold the flywheel from rotating or just use an impact wrench to loosen the nut (if it is powerful enough)

Writeup: Ignition Control Module (ICM) harness repair Starterringlockdown

I hope this makes sense as my pics are sorely lacking here.

after the flywheel is locked down, put a cheater bar on your wrench and rotate the balancer bolt towards the rear of the car. it will take 300-400 lbs. if the vice-grips slip off start over.

OK Mr extreme bolt came off and you are now ready to remove the balancer...

attach the puller with the 3 bolts... you may need to run and get some long bolts... they are 1/4" fine thread and about 3-1/2" long if i remember.... please double check. put the top bolt in first, then insert a small deep well socket in the harmonic balancer. the bolt hole is deep and you will likely need it unless your puller has a very long center bolt. you will be pushing the large puller bolt at the back of the pulley.

Writeup: Ignition Control Module (ICM) harness repair Balancerpuller

snug all three of the small puller bolts against the balancer and then tighten the big bolt down. the balancer should come off without too much stress. maybe 50 - 80 ft-lbs of turning force.


BAM!!! balancer is off! hardest part is done... grab a beer and show your wife what a handy dude you are and appreciate the fact that you are an animal

Writeup: Ignition Control Module (ICM) harness repair Balancerremoved

Now take a look at your balancer shaft... is there a groove in it? if yes you have to put a sleeve over it (NAPA for $40, Auto Zone for $10 - both Felpro) I didnt think twice about this and sure as hell my balancer leaked bad... so off it came and once fixed, no leaks.

It comes with important instructions that need to be followed carefully and locktite to secure the ring. BE SURE YOU PUT IT ON STRAIGHT WITH A PIECE OF WOOD. I cleaned the shaft and inside of the balancer with brake cleaner before installing the sleeve

Writeup: Ignition Control Module (ICM) harness repair Balancergroove

Writeup: Ignition Control Module (ICM) harness repair Balancersleeve


Last edited by jeffyd123 on Mon Jun 21, 2010 10:23 pm; edited 2 times in total
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jeffyd123
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Name : Jeff Del Vechio
Joined : 2010-03-15
Post Count : 108
Merit : 4

Writeup: Ignition Control Module (ICM) harness repair Empty
PostSubject: Re: Writeup: Ignition Control Module (ICM) harness repair   Writeup: Ignition Control Module (ICM) harness repair EmptySun Jun 20, 2010 11:51 pm

OK... the crank sensor is covered by a plastic shield... pull it stright forward... there are no bolts... its a snap fit thingy.

Writeup: Ignition Control Module (ICM) harness repair Balancerring

Writeup: Ignition Control Module (ICM) harness repair Balancerring2



there it is.. the crank sensor yank that sucka!

Writeup: Ignition Control Module (ICM) harness repair Cranksensor

and the crank sensor plug... note how its routed under the AC mount... that will not cut it for me. I'm lengthening both leads on the crank and cam sensors so they aren't up against the motor anymore... no more melting! more on that later.

Writeup: Ignition Control Module (ICM) harness repair Cranksensorplug

The next shot shows where the cam sensor mounts (i already pulled it). the plug is impossible to remove without major dissasembly so we are going to cut it a bit later. if you want you can get a mirror and verify the magnet is in there.

Writeup: Ignition Control Module (ICM) harness repair Camsensor

OK now pull the seal if you want to... it took me while to do it and it wasnt pretty. I had to gently tap a screwdriver under the blue flange and work it around. I applied grey silicone high-temp sealer around the outer and pressed flange (very thin amount) and tapped it back in using a piece of 2 X 4 and a hammer, be careful not to bend the dam thing! gently work it back in.

go ahead and replace the cam and crank sensors... might as well clean up the area around these holes too.

On to replacing the ICM harness
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jeffyd123
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Name : Jeff Del Vechio
Joined : 2010-03-15
Post Count : 108
Merit : 4

Writeup: Ignition Control Module (ICM) harness repair Empty
PostSubject: Re: Writeup: Ignition Control Module (ICM) harness repair   Writeup: Ignition Control Module (ICM) harness repair EmptyMon Jun 21, 2010 12:10 am

Now the ICM harness is kind of tricky.

it comes out of the ICM... goes under the ICM, under the SC snout, comes out of the snout and terminates in an 8-pin plug. where it is under the SC, it branches off to the cam sensor just on the left side of the water pump... forget trying to remove it... i tried for 2 hours and was not happy with GM to say the least. Why they routed wires right against the head is beyond stupid.

Writeup: Ignition Control Module (ICM) harness repair Undericmharnesses2

here's what my cam sensor branch looked like.. not pretty. you cant really see it but there are 3 bare wires in there.. that does not make for a happy riviera. and man did it let me know about it. By the way.. this happens a lot to our cars so be prepared to do this step. fortunately its not as hard as i thought it would be... took about 3 hours total.
Writeup: Ignition Control Module (ICM) harness repair Crackedwires

Writeup: Ignition Control Module (ICM) harness repair Crackedwires2

First remove the ICM plug... I removed the whole ICM mount and all but you dont need to if you dont want to. just a note... the ICM also has a problem with getting corrosion under it. it can be removed off the engine mount with 3 small nuts under the ICM plate... if its corroded... clean it with 600 - 800 grit or finer sandpaper and then clean off all the grit.

Writeup: Ignition Control Module (ICM) harness repair Icmbottom

now unplug the 8-pin plug to the rear of the SC... its got a lock pin in it.
find the cam sensor wire where it popps up through the water pump and gently pull it up as far as you can. cut it near the main ICM harness trunk and pull it through the bottom.

Off to the bench! Lets fix this thing so our cars dont make us have a heart attack when they sputter and die in the middle of an intersection at rush hour
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jeffyd123
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Name : Jeff Del Vechio
Joined : 2010-03-15
Post Count : 108
Merit : 4

Writeup: Ignition Control Module (ICM) harness repair Empty
PostSubject: Re: Writeup: Ignition Control Module (ICM) harness repair   Writeup: Ignition Control Module (ICM) harness repair EmptyMon Jun 21, 2010 1:36 am

get the harness on the bench and remove all the tape and grease and shit and crap and other what-nots our poor cars have to trudge through everyday.

clean off the plugs VERY WELL. I had to use brake cleaner on them... spraying directly into the contacts and them tapping them (contacts down) on a rag to get the grease out. I had to repeat this about 8 times per plug (not the ICM plug though). be sure to remove the rubber gasket from the plug first.

I put the ICM plug on my bench and put a furniture clamp snugly on it.. then I used a clamp on vise to hold the 8-pin plug so it stretched the harness in front of me. sorry the pics are so bad... im not too familiar with my camera yet.

Writeup: Ignition Control Module (ICM) harness repair Harnessbench1

Very carefully inspect the wires... I used some 4X goggles so I could look at them and really see the damage in there where it was pressed up to the head. You will need to formulate where you are going to be cutting and splicing new wires in.

I decided I was going to extend the main part of the harness about 3", the Crank sensor about 8" and the cam sensor about 15".

So you say... "Hey Jeff, aside from you being about the worst mechanic I've ever seen? why the hell would you want to change the length of these cables?"

Well, I wanted the 8-pin plug to be flexible in its position and to give me a little breathing room to adjust for the cam sensor branch.

I also wanted the cam sensor to route behind the alternator, wire tie to the main harness where the oil sensor, speed sensor, knock sensor and power steering sensor. these wires go nicely down the side of the motor and as long as they are away from the header... will be nice and safe from the heat of the engine. When you get under the car and look, you will see. The cam sensor wire will then nicely float over the cam sensor. its a beautiful thing and its easy to service too.

ditto for the crank sensor... its going to route down the other side of the motor, curl under the AC compressor and slip neatly into the CKP sensor.

so there... and I am a great mechanic thank you very much! I did build a 4 X 4 '69 Cadillac limo when I was 18... weighed 3 tons and got 4 MPG. I miss Sherman (but not the gas mileage)

So I digress....

Lets prep for our wiring session.....

The crimps from AutoZone are great! They make a very good connection (I crimp each side of the connection 1 time straight across the connector and then 1 time on a 45 degree) Be sure to make a good, clean strip about 1/4" long... the stripped wire should NOT stick out of the metal part of the crimped connector. I also tightly twisted each strip before inserting it. Take your time here.... be sure those crimps are right and making strong contact. DO NOT OVER CRIMP the connectors... you need about 40lbs of force to properly crimp them... any more and you will cut the insulation of the connector.

When making a connection, carefully insert the twisted wire in to the connector, then make 1 90 degree crimp as near to the end of the metal crimp as you can without the crimper sliding off the crimp. then insert the other wire and do the same 90 degree crimp as near the end of the crimp as you can. next, when the 2 are connected (check it) crimp closer to the center of the metal crimp at a 45 degree angle for each side. now you have a strong connection that will last for years.

Next, when cutting, crimping, be sure to check the length of the wires so they are even overall as a harness... this will make the final wire wrapping easier and cleaner.

Lastly, you WILL NEED THIS SCHEMATIC! so print it out and refer to it with every cut/splice you make then refer to it again! you can easily make a mistake here... especially with the 2 white wires. also, note on the ICM plug, the letters "I" and "O" are not used.

Writeup: Ignition Control Module (ICM) harness repair Icmscematic


Here we go...

I started with my crank sensor branch first. you will see how the wires bend to make the branch. I made my calculations, figured out where the wires were bad and cut it near the branch and about 3" from the CKP plug. I cut the wires at the same point on this part of the harness, but staggered them on the main and cam portions so there wasnt a lot of lumpy spots.

Writeup: Ignition Control Module (ICM) harness repair Harnesscloseup

After the crank branch was done, I calculated where my cam brach was going to be... you will notice that it tend to branch under the SC snout but I wanted to move toward the 8-pin plug about 6 more inches. I made my cuts on the cam sensor branch and extended the wire to about 20". it branches about 5" from the 8-pin plug.

while making these calculations, you will need to determine if you can use the pre-made branches that are already on the harness ( I did). Again do some head scratching and dont hurry. My harness was in decent shape aside from some badly worn insulation and bare wires on the cam branch. yours may vary from mine.

Once you have your cam branch extended and calculated where it will branch, cut the remaining wires that connect the 8-pin plug to the ICM plug... move your clamps/vises apart about 4 more inches from where they currently are and start splicing the wires together. You will be making staggered splice/cuts here so do some head scratching. be sure you dont splice in a bad wire!

Writeup: Ignition Control Module (ICM) harness repair Harnesscloseup2

When all the crimps are done, use a heat gun to shrink the insulation that extends beyond the metal crimps inside the connectors. you will see the wire sort or "anneal" itself to the heat shrink... very cool crimps!

Almost done! tape wrap a few key parts of it so it keeps its shape and orientation.

Now do a quick test of the connections also checking the cross jumps between the cam and crank plugs. if its good wrap the entire thing with quality electric tape. give lots of extra wraps at the branches, then wrap it one more time just to help protect it.

Mine came out like this..

Writeup: Ignition Control Module (ICM) harness repair Harnessdone

Now put the corrugated over it and install it.

I fished the cam plug under the SC snout, then the 8-pin. route the cam plug down the side of the engine and wire-tie it to the other harness mentioned above. then slip it over and plug it in tot he cam sensor. If you want, take off the alternator so you can see better... I did.

Writeup: Ignition Control Module (ICM) harness repair Camwire

run the remaining part of the harness under the snout and keep it off the head by using the coolant bypass hose. the harness should then route over the big radiator hose and be on the the drivers side of that hose. place the ICM back on its mount and be sure the ground wire has enough room to allow the ICM plug to go in without straining the ground wire.

now run the crank plug on the drivers side of the radiator hose and under the AC compressor. there is a nice groove to fit the wire in but dont do that yet. I wire tied the harness to a power steering hose that was behind the bottom of the radiator... be sure to give it slack for when the engine moves under acceleration.

Writeup: Ignition Control Module (ICM) harness repair Crankcable



You need to put the plastic ring on its 3 snap-fit mounts first., then plug in the wire.

Carefully line up the keyway on the harmonic balancer and slide it on as far as you can. then brace the flywheel with the vice grips (for the rear side of the tranny case this time) and tighten that monster bolt back on there.... it needs about 300ft/lbs so crank it on there. reove the vice grips and reinstall the starter ring gear/flywheel cover.

finish hooking up the ICM plug, reinstall the metal cover plate under the ICM so the wires dont get eaten by the belts...

put your SC and accessory belts back on the car. and do a check of your wiring... is it away from the hot parts of the engine???
is it clear and going to stay clear of the belts????
is the little ground wire on the ICM harness strained?


Do a final check under the hood for tools and rags, hook up the battery and turn the key on for about 10 seconds, then start her up.... hopefully all will run well.

In my case I still had a bad ICM (despite autozone bench testing it - the failure happened when the ICM warmed up) so I had to do hours more diagnostics. I wound up getting a rebuilt PCM and then tried a new ICM before my car would run right. OH well, my car should run good for while now with no more electrical gremlins.... hopefully

Hope this helps you guys... this harness appears to be a problem for the car and seeing as they aren't available anywhere I see this as the only option.

You dont have to do the sensors in this repair... I just included them for informational purposes.

Jeff


Last edited by jeffyd123 on Mon Jun 21, 2010 10:29 pm; edited 2 times in total
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albertj
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albertj

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Writeup: Ignition Control Module (ICM) harness repair Empty
PostSubject: Re: Writeup: Ignition Control Module (ICM) harness repair   Writeup: Ignition Control Module (ICM) harness repair EmptyMon Jun 21, 2010 2:15 am

THank you very much for the writeup.

When the time is right I think Ed needs to be aware that $175, say, for the wiring harness is preferable to cutting it. My point is that some money say $25 for the additional labor to take out the alt and PS seems fair; the alternator bracket is a little time consuming but sits on top of the engine and is not at all that difficult, and admittedly the PS bracket is a bit of a reach. On the other hand we're talking about pulling parts from a nonrunning car; the alt and PS pump can be sold at some point for cars besides the Riv and splicing the ICM is a pain for customers and introduces a wire-bundle full of potential failure points -- especially compared to the time to pull those other parts.

Maybe someone can point Ed to this writeup (Rick?), he'd probably want to know. I plan to if the occasion arises.

Albertj
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jeffyd123
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Writeup: Ignition Control Module (ICM) harness repair Empty
PostSubject: Re: Writeup: Ignition Control Module (ICM) harness repair   Writeup: Ignition Control Module (ICM) harness repair EmptyMon Jun 21, 2010 3:48 am

You're welcome albert.

I never put Morad's harness in... I am trying to get my money back for it.
I was fine with the price, but I expected the entire harness for that price. They should mention that they dont include the ICM harness... I wouldnt have bought it if I knew that.

It worked out OK as Im very happy with my new ICM harness.. . just added some time for making it and its better than the original.
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albertj
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Writeup: Ignition Control Module (ICM) harness repair Empty
PostSubject: Re: Writeup: Ignition Control Module (ICM) harness repair   Writeup: Ignition Control Module (ICM) harness repair EmptyMon Jun 21, 2010 4:00 am

Yeah, I wonder if Ed has an apprentice who pulled the harness and so had no idea what got sent. It's kind of an obvious problem, I don't see what's right about a harness with pieces missing.

Albertj
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