Ground to pcm makes it run right? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Roostboy102 · 06-16-2013, 12:06 AM

What do I have wrong if my pcm needs a ground wire? Yes, the actual pcm! Once this is grounded all is well and it runs great. I came upon this with a LOT of trial and error!
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**truckdude239** · 06-16-2013, 03:47 AM

Runn a wire?
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Russell · 06-16-2013, 04:30 AM

I have heard of similar happenings if you accidentally overload and burn out the internal ground on an Allison TCM by boosting through the TCM's cooling fins by accident. I suppose it is possible the same thing could happen to a PCM, but I have not heard of it before.

As suggested just above me, folks who have accidentally fried their TCM's internal ground are able to get it to work fine by running a ground strap from the TCM's cooling fins to chassis ground. Its kind of a hokey way of doing things, but it'll do until you decide to buy a new PCM...

BTW, I have EFI Live and I can download the software on your PCM and transfer it to a new PCM for the cost of a license if you want. It's something like 120 to 130 bucks for a license.

Roostboy102 · 06-16-2013, 08:03 AM

Ok I mean I have a wire on it, it just didn't seem right so I thought I would ask.
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06-16-2013, 12:06 AM	#1
Roostboy102 Registered User Join Date: Jan 2012 Location: Amish Country Posts: 138	Ground to pcm makes it run right? What do I have wrong if my pcm needs a ground wire? Yes, the actual pcm! Once this is grounded all is well and it runs great. I came upon this with a LOT of trial and error! Posted via Mobile Device __________________ 72 C10 - Multicolor, 4.8 ls, NV3500. Sold 72 K5 - Under Construction

06-16-2013, 03:47 AM	#2
truckdude239 Senior Member Join Date: Sep 2005 Location: Lewisville, Nc Posts: 10,237	Re: Ground to pcm makes it run right? Runn a wire? Posted via Mobile Device __________________ David fuller Ase Certified Mechanic Click here to help support our board!! 1971 Chevy c-10 under going a 4.8l LSx swap Build Thread http://67-72chevytrucks.com/vboard/s...d.php?t=421305 2007 Honda Accord my daily 145kmiles 2002 Honda Accord 4 door With 330k(sisters car) 2005 toyota Avalon 228k( brothers car) 2002 Sububran 5.3 245k 2000 Tahoe 5.3l 378 General manager for Marco's Carwash & lube

06-16-2013, 04:30 AM	#3
Russell Professional Grade Join Date: May 2003 Location: Fort McMurray, Alberta Posts: 7,915	Re: Ground to pcm makes it run right? I have heard of similar happenings if you accidentally overload and burn out the internal ground on an Allison TCM by boosting through the TCM's cooling fins by accident. I suppose it is possible the same thing could happen to a PCM, but I have not heard of it before. As suggested just above me, folks who have accidentally fried their TCM's internal ground are able to get it to work fine by running a ground strap from the TCM's cooling fins to chassis ground. Its kind of a hokey way of doing things, but it'll do until you decide to buy a new PCM... BTW, I have EFI Live and I can download the software on your PCM and transfer it to a new PCM for the cost of a license if you want. It's something like 120 to 130 bucks for a license. __________________ 1995 Chevrolet 2 Door Tahoe (6.6L LBZ Duramax / ZF6 / NP241 with 1 ton solid axle swap)

06-16-2013, 08:03 AM	#4
Roostboy102 Registered User Join Date: Jan 2012 Location: Amish Country Posts: 138	Re: Ground to pcm makes it run right? Ok I mean I have a wire on it, it just didn't seem right so I thought I would ask. Posted via Mobile Device __________________ 72 C10 - Multicolor, 4.8 ls, NV3500. Sold 72 K5 - Under Construction



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