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.
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.
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.
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!
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..
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.
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.
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.