ICM Problems??

02BlueGT · 03-29-2008, 03:00 PM

Could a bad ICM cause a rough Idle, but not cause problems elsewhere? Cause I've eliminated most other options, and before I go invest in a new ICM I'd like opinions if it could f-up the idle only.

The car runs fine at any engine speed above 1300 rpm, in the 900 - 1250 rpm range there is a slight miss, and at idle it is rough, sometimes even stalling out, new plugs, swapped out the coils for a new one, no change... eliminated all other options than a bad ICM or possibly a screwed up PCM

SyntheticShield · 03-29-2008, 03:09 PM

I dunno, the ICM would not be my first thought in that. Its not unheard of that they go bad, but its not all that common either.

Dont get me wrong, its entirely possible, but with a rough idle and stalling, I would be looking more in the direction of the IAC, MAF, that sorta thing. Just because you didnt mention it, and because you've changed the plugs and coils, might be worth looking at the plug wires. Though even those wouldnt pop to the top of my list.

Are there any codes, SES light on or flashing or anything like that?

turbocharged406sbc · 03-29-2008, 09:11 PM

hey dave i've got a known good ICM to swap on and try out... call me

02BlueGT · 03-30-2008, 01:53 AM

Ive tried all sensors and none are causing the problem, I have no ses light,(other than when I was checking sensors) I am running out of ideas on what it could be hence why I'm looking at icm, Like if it has an idle circuit in it or something that is bad.... but now that I think of it,a open in a spark plug wire may cause this... but it isnt constant.... this one is a real head scratcher

I'll give you a call this week if I need and thanks for the offer schlim

archemedes · 03-30-2008, 02:16 AM

I have had one cause some weird issues, especially after warmed up

turbocharged406sbc · 03-30-2008, 02:26 AM

when you threw in new plugs are you using the same ignition cables?

02BlueGT · 03-30-2008, 11:37 PM

Yeah, the cables have less than 8k as did the plugs, but plugs were cheap, and old ones were a heat range colder and with all my short trips got pretty fouled

turbocharged406sbc · 04-01-2008, 03:41 AM

i'm in the garage today (well after i get a couple hours of sleep!) eric and I got several of the aluminum pieces bent for the new massive whipple TB plenum ( said the hell with it and it'll now put the TB ~1 ft behind the drivers headlight...good fer the track too

)

02BlueGT · 04-02-2008, 01:59 AM

Well, swapped the ICM, no change.... now time for wires, This is becoming such a headache

turbocharged406sbc · 04-02-2008, 02:16 AM

Quote:

Originally Posted by 02BlueGT

Well, swapped the ICM, no change.... now time for wires...

was worth a shot....

Quote:

Originally Posted by 02BlueGT

This is becoming such a headache

If it has Tits or wheels....it will give you ****

03-29-2008, 03:00 PM	#1
02BlueGT GTX Level Member Join Date: Jan 2008 Location: Hoffman/Schaumburg, IL Posts: 852 Thanks: 14 Thanked 8 Times in 8 Posts iTrader: (0)	ICM Problems?? Could a bad ICM cause a rough Idle, but not cause problems elsewhere? Cause I've eliminated most other options, and before I go invest in a new ICM I'd like opinions if it could f-up the idle only. The car runs fine at any engine speed above 1300 rpm, in the 900 - 1250 rpm range there is a slight miss, and at idle it is rough, sometimes even stalling out, new plugs, swapped out the coils for a new one, no change... eliminated all other options than a bad ICM or possibly a screwed up PCM __________________ 2002 GT...Wizardair, ZZP 2.5 o/r dp, Special Eddition two-tone leather interior added, HUD added, 12" Brake Upgrade, ZZP strut tower bars, gmpp sway bars,-6an braided SS fuel hoses , Hptuned, Top Swaped..... I've got Boost!! I've got only 1.5* KR left my poor L36 block.....

03-29-2008, 03:09 PM	#2
SyntheticShield Administrator Join Date: Dec 2007 Location: Oklahoma Posts: 6,508 Thanks: 14 Thanked 46 Times in 32 Posts iTrader: (5)	Re: ICM Problems?? I dunno, the ICM would not be my first thought in that. Its not unheard of that they go bad, but its not all that common either. Dont get me wrong, its entirely possible, but with a rough idle and stalling, I would be looking more in the direction of the IAC, MAF, that sorta thing. Just because you didnt mention it, and because you've changed the plugs and coils, might be worth looking at the plug wires. Though even those wouldnt pop to the top of my list. Are there any codes, SES light on or flashing or anything like that? __________________ Scotty Hall Bartlesville, OK 2001 Pontiac Grand Prix GTP It whines a lot, but I like it. The only limitation you will ever face in life is yourself!

03-29-2008, 09:11 PM	#3
turbocharged406sbc Community Vendor Join Date: Jan 2008 Location: hangover park IL, in the garage working on one of 12 3800's Posts: 190 Thanks: 0 Thanked 0 Times in 0 Posts iTrader: (0)	Re: ICM Problems?? hey dave i've got a known good ICM to swap on and try out... call me __________________ ~James~ Psychotic Gearhead 1994 Olsmobile 442 (462ci-4wd-2 engines) L67/4t80e^2 projects: 3800 SI/SII hybrid talldeck, longrod w/ SII symetrical port heads 98 WhippledRiv & 97 GTP www.sinisterdragdesign.com dragwhore

03-30-2008, 01:53 AM	#4
02BlueGT GTX Level Member Join Date: Jan 2008 Location: Hoffman/Schaumburg, IL Posts: 852 Thanks: 14 Thanked 8 Times in 8 Posts iTrader: (0)	Re: ICM Problems?? Ive tried all sensors and none are causing the problem, I have no ses light,(other than when I was checking sensors) I am running out of ideas on what it could be hence why I'm looking at icm, Like if it has an idle circuit in it or something that is bad.... but now that I think of it,a open in a spark plug wire may cause this... but it isnt constant.... this one is a real head scratcher I'll give you a call this week if I need and thanks for the offer schlim __________________ 2002 GT...Wizardair, ZZP 2.5 o/r dp, Special Eddition two-tone leather interior added, HUD added, 12" Brake Upgrade, ZZP strut tower bars, gmpp sway bars,-6an braided SS fuel hoses , Hptuned, Top Swaped..... I've got Boost!! I've got only 1.5* KR left my poor L36 block.....

03-30-2008, 02:16 AM	#5
archemedes Approved Vendor Join Date: Jan 2008 Location: Saraland Alabama Posts: 3,462 Thanks: 0 Thanked 3 Times in 3 Posts iTrader: (1)	Re: ICM Problems?? I have had one cause some weird issues, especially after warmed up __________________ Steve '97 GTP VS cam, ZZP PCM, and not much else yet

ICM Problems??

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03-30-2008, 02:26 AM	#6
turbocharged406sbc Community Vendor Join Date: Jan 2008 Location: hangover park IL, in the garage working on one of 12 3800's Posts: 190 Thanks: 0 Thanked 0 Times in 0 Posts iTrader: (0)	Re: ICM Problems?? when you threw in new plugs are you using the same ignition cables? __________________ ~James~ Psychotic Gearhead 1994 Olsmobile 442 (462ci-4wd-2 engines) L67/4t80e^2 projects: 3800 SI/SII hybrid talldeck, longrod w/ SII symetrical port heads 98 WhippledRiv & 97 GTP www.sinisterdragdesign.com dragwhore

03-30-2008, 11:37 PM	#7
02BlueGT GTX Level Member Join Date: Jan 2008 Location: Hoffman/Schaumburg, IL Posts: 852 Thanks: 14 Thanked 8 Times in 8 Posts iTrader: (0)	Re: ICM Problems?? Yeah, the cables have less than 8k as did the plugs, but plugs were cheap, and old ones were a heat range colder and with all my short trips got pretty fouled __________________ 2002 GT...Wizardair, ZZP 2.5 o/r dp, Special Eddition two-tone leather interior added, HUD added, 12" Brake Upgrade, ZZP strut tower bars, gmpp sway bars,-6an braided SS fuel hoses , Hptuned, Top Swaped..... I've got Boost!! I've got only 1.5* KR left my poor L36 block.....

04-01-2008, 03:41 AM	#8
turbocharged406sbc Community Vendor Join Date: Jan 2008 Location: hangover park IL, in the garage working on one of 12 3800's Posts: 190 Thanks: 0 Thanked 0 Times in 0 Posts iTrader: (0)	Re: ICM Problems?? i'm in the garage today (well after i get a couple hours of sleep!) eric and I got several of the aluminum pieces bent for the new massive whipple TB plenum ( said the hell with it and it'll now put the TB ~1 ft behind the drivers headlight...good fer the track too ) __________________ ~James~ Psychotic Gearhead 1994 Olsmobile 442 (462ci-4wd-2 engines) L67/4t80e^2 projects: 3800 SI/SII hybrid talldeck, longrod w/ SII symetrical port heads 98 WhippledRiv & 97 GTP www.sinisterdragdesign.com dragwhore

04-02-2008, 01:59 AM	#9
02BlueGT GTX Level Member Join Date: Jan 2008 Location: Hoffman/Schaumburg, IL Posts: 852 Thanks: 14 Thanked 8 Times in 8 Posts iTrader: (0)	Re: ICM Problems?? Well, swapped the ICM, no change.... now time for wires, This is becoming such a headache __________________ 2002 GT...Wizardair, ZZP 2.5 o/r dp, Special Eddition two-tone leather interior added, HUD added, 12" Brake Upgrade, ZZP strut tower bars, gmpp sway bars,-6an braided SS fuel hoses , Hptuned, Top Swaped..... I've got Boost!! I've got only 1.5* KR left my poor L36 block.....

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