Mounting PCM in engine bay
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Joined: Apr 2002
Posts: 1,704
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From: Roscoe, IL
Car: 1991 Trans Am
Engine: LQ4
Transmission: T-56
Axle/Gears: 3.70
Mounting PCM in engine bay
I saw the thread about making a hole and mounting it under the dash but my downpipe prevents that from happening, and I have contemplated extended the harness Pocket style, but I really really hate soldering. So who has mounted the PCM in the engine bay or in the fender?
Joined: Mar 2001
Posts: 10,405
Likes: 2,081
Car: '89 Firebird
Engine: 7.0L
Transmission: T56
Re: Mounting PCM in engine bay
I have air conditioning so I am considering putting it inside the passenger side fender. Not sure yet how many wires I'll have to extend to reach.
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Joined: Mar 2004
Posts: 250
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From: NE Pa
Car: 1989 Iroc-Z Convertible
Engine: 6.0 LQ4 LSX
Transmission: T56
Axle/Gears: Moser 12 bolt w/4.11s
Re: Mounting PCM in engine bay
I am planning on installing my pcm in the same location as five6kid
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Posts: 3,079
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From: Pepperell, MA
Car: 1987 Trans Am
Engine: LQ9/L92
Transmission: 4L60E
Re: Mounting PCM in engine bay
if you swap out the overflow bottles for a set of the 4th gen ones (washer in front of radiator, overflow under the battery), you could use the area in front of the strut towers as well. i opted to extend the harness and run it through the factory grommet in the passenger fender well.
Joined: Mar 2000
Posts: 43,187
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From: Littleton, CO USA
Car: 82 Berlinetta/57 Bel Air
Engine: L92/LQ4 (both w/4" stroke)
Transmission: 4L80E/4L80E
Axle/Gears: 12B-3.73/9"-3.89
On the LS1/T56 car, I have the AC housing, and ran the PCM harness into the passenger compartment without lengthening the harness. I did strip out some unused wires to reduce the bundle size. It would be easier with a lengthened harness, but is do-able with a factory harness. I wrapped the harness in heat shielding tape (the headers are ceramic coated as well).

With the HVAC housing back in:

With the HVAC housing back in:
Re: Mounting PCM in engine bay
On the LS1/T56 car, I have the AC housing, and ran the PCM harness into the passenger compartment without lengthening the harness. I did strip out some unused wires to reduce the bundle size. It would be easier with a lengthened harness, but is do-able with a factory harness. I wrapped the harness in heat shielding tape (the headers are ceramic coated as well).


Not to hi jack the thread, but...
Is that the Autometer coolant sensor and the adapter for such. If so, is it tightened completely? Which one of the sensors is it?
I have built my harness so that I am using the autometer sensor in the passenger location. Seems as if that particular setup sticks out quite a bit.
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Joined: Mar 2000
Posts: 43,187
Likes: 42
From: Littleton, CO USA
Car: 82 Berlinetta/57 Bel Air
Engine: L92/LQ4 (both w/4" stroke)
Transmission: 4L80E/4L80E
Axle/Gears: 12B-3.73/9"-3.89
Yes, that is the Autometer engine temp sender. I'm not that fond of it, either. This is tightened all the way. It works fine, though.
I have a combined CTS and engine temp sender in the other car.
I have a combined CTS and engine temp sender in the other car.
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Joined: Aug 2008
Posts: 706
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From: Dixon, IL
Car: 91 RS
Engine: LTwon
Transmission: T-56
Axle/Gears: Both
Re: Mounting PCM in engine bay
Intimidator used his stock AC heater box, and put it where the condenser would go, hides it very nice. Only works if your deleting ac of course
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From: Home of most 3rd gens Van Nuys, CA
Car: 1987 IROC
Engine: Turbo 293ci 4.8l
Transmission: T56
Re: Mounting PCM in engine bay
like cprmn14 said mine is mounted in the AC heater box on my 91z. if you lay it a different way and add some sheet metal i believe you can still keep the heater.


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Joined: Apr 2006
Posts: 685
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From: CT
Car: 1988 Iroc
Engine: 5.7L
Transmission: '96 T56, Hurst Shifter, Mech VSS
Axle/Gears: 3.45 9 Bolt
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