LD9 ICM Woes? - Maintenance and Repair Forum

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LD9 ICM Woes?
Saturday, January 18, 2014 11:22 PM
!!! I already plan on swapping to the 2.2/2200/LN2 Coil setup, I already know the advantages of it and don't need 1/2 the replies to be "GO LN2 COILS" rather than discussing the issue at hand !!!

Now that I got that out of the way. I'm just curious as to find out what this issue is exactly I've already narrowed it down but i'll give the same summary I posted on some various FB Groups.

Plan on swapping to LN2 coils anyway, but this sound arose after swapping plugs, car drives fine upto 5-6k WOT where it begins to misfire and throws a P0336 code. Plugs were all properly gapped at .035, NGK TR6 4177. Car idles smooth, Think it might be due to: Non properly seated boots/dirty connectors/bad ground(Or missing..) strap on the idi cover. I don't believe it is the plugs but rather something in the ICM that is disturbed whenever the idi cover is taken off, since it has happened before when I was merely switching to the HO Idi cover, minus this ticking noise.

More info: I tested the plugs before torquing down the idi cover by just seating the boots and turning on the car, it idled silky smooth at 1,500rpm before warming up and dropping to around 1,090rpm, but if I gave it any gas the RPM's would drop, let go and it'd return to normal idle, not shaky rpm drop, but a very slow smooth rpm drop if i give it gas. Torqued the IDI cover down and I could rev it fine. I believe I might be missing a ground strap and the edges of the IDI cover are grounding on the cam tower's... I honestly cant remember if I am missing it since I worked on it dead tired and horribly sick so my memory is faltering.

Tomorrow I plan on pulling the IDI Cover again and: Cleaning the boots, Looking for Ground Strap if I put it on afew months ago when I swapped covers, If not, figure out a new grounding solution, checking/cleaning the ICM plug.

My biggest bet is on the Lack of a Ground Strap, since I experienced a misfire/no spark issue afew months ago when I swapped IDI cover's, after getting home and re-torquing the IDI cover bolts, the next day the issue was no longer present. I'm just posting this here to pick everyone's brains and to see what people think.

Lastly, A video of the noise, sorry for the quality, I took it in MMS mode to text it so it's compressed as hell. The sound is heard right around 14 Seconds.



EDIT: Posters who had related issues:

http://www.j-body.org/forums/read.php?f=2&t=435763&a=2

http://www.j-body.org/forums/read.php?f=2&t=399148&a=1

Alex Richards wrote:

Check ALL the grounds. I had a horrible (indrivable) misfire in my 2200 and after throwing a @!#$ ton of money at the problem I discovered one of the ground straps came loose. Took 10 mins to fix and zero dollars.

Electrical problems really are rediculously easy when you go about finding them with the proper tools and equipment and dont just guess where the problem might be.


But the also weird thing is that the ICM has its own ground wire in the plug..


Edited 2 time(s). Last edited Saturday, January 18, 2014 11:45 PM



Re: LD9 ICM Woes?
Sunday, January 19, 2014 8:12 AM
Your having a grounding issue.

Check the yellow and purple wire to the crank position sensor...up to the ICM. Also, I'm about 90% sure the ICM is toast now. Also, your white IDI housing might be shot also, allowing spark to go places it shouldn't.





PRND321 Till I DIE
Old Motor: 160whp & 152ft/lbs, 1/4 Mile 15.4 @88.2
M45 + LD9 + 4T40-E, GO GO GO
Re: LD9 ICM Woes?
Sunday, January 19, 2014 8:13 AM
Add a temporary ground strap from one of the IDI bolts to the battery after you re-add the ground strap inside the IDI housing. That has fixed a few misfire issue on mine and others cars.




PRND321 Till I DIE
Old Motor: 160whp & 152ft/lbs, 1/4 Mile 15.4 @88.2
M45 + LD9 + 4T40-E, GO GO GO
Re: LD9 ICM Woes?
Sunday, January 19, 2014 2:35 PM
I'll see if I can't dig up that grounding strap. If I can't find it, is it passable to use some 10-16~ gauge wiring to serve the same purpose?



Re: LD9 ICM Woes?
Sunday, January 19, 2014 6:23 PM
Update:

I pulled apart the IDI housing and cleaned out what I could get to, Springs, Boots, the 3 pin plug from the ICM and the female and male ends of the ICM plug, Boots and springs were very dirty. There was no ground strap but I have not been running a ground strap for the past 4 months since I swapped IDI cover's so I admittedly didn't bother with it. I put it all back together and torqued the cover back down. Ticking noise is still present but is quieter and lasts half as long (It was like this also when I got up this morning and checked again before I did any of this work). Car revs freely upto redline in neutral and WOT to redline in 1st and 2nd is fine with no hesitation and good throttle response, car pulls a tiny noticeable difference harder and is a tad louder exhaust wise. Idle is smooth, No code thrown so far. When I inspected the IDI system there were no cracks or melted spots, it looked the exact same as it did 4 months ago.

So no more misfiring (so far), car runs abit better, ticking still there but quieter and doesn't last as long, IDI system does not visually appear damaged.



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