DT69cam

Where did you guys mount your ECM and did you make a custom bracket ?

Project GatTagO

iTrader: (7)

Man, I am curious too. I was working on a 69 Camaro the other day and the guy was using a 411 ECU and that damn thing is ******* huge!!! He has vintage air under the dash and there just isn't any space at all. I think he was going to have a bracket made to mount it above the vintage air and vertical in front of the glove box door. Glove box will be eliminated.

I am curious to see what others have done.

Andrew

robm-951

iTrader: (6)

I lengthened my harness and mounted the ECM under the front passenger side fender behind the battery. It's hidden yet easy to get to.

bczee

iTrader: (12)

On my Chevelle, , I used a F-Body mount and mounted it inside on top of the Trans Tunnel, built a console to cover it.

On my Nova, I mounted it the Dash, above the ash tray, Built a custom mount with sheet metal. IIRC, 1st Gen F-Body should have the same area also as my 3rd Gen X-Body. (see my build tread).

Both of them, I was able to redo the harness and stretch it out to mount the PCM inside.

BC

Michael Yount

iTrader: (1)

08 Corvette ECU and PSI Conversions harness and relay/fuse block. ECU screws straight into the unibody (I wanted a little heat-sink effect) but I made a bracket to put the relay/fuse block where you see it. This is mid-mockup; Wiring and such is cleaned up and out of the way. This is the passenger footwell.

ls1nova71

iTrader: (4)

My Nova has Vintage Air so I mounted my PCM on the firewall under the right fender where the old blower motor used to be. About the same location as a 4th gen camaro so the harness fit perfectly.

SS69LS1

iTrader: (108)

I typically put it above the glove box opening, but with a 411 type ecm it can be a bit tight. It will work though. On my current build, I drilled the trans tunnel on the pass side. There's a small flat area just inside the tunnel where it meets the firewall. Ran the harness thru and mounted the ecm on edge on the trans tunnel, up against the inside of the firewall. Just enough room to fit the vintage air unit in front of it. Harness is totally hidden.

gofastwclass

iTrader: (2)

What is wrong with leaving PCM's in the engine bay like GM designed it? Are we all afraid of getting them wet?

My Thunderbird PCM is mounted behind the bumper. My Impala PCM is on the core support, a different Impala I built was on the inner fender and a third was on the firewall behind the inner fender. The K5 ECM and TCM are under the battery, a 90's Cadillac was on the fender well, etc... Most of these were hidden in plain sight and I actually had people ask where the PCM was while standing within arms reach of it!

Michael Yount

iTrader: (1)

Anything you can do to keep that electrical component cooler and drier is an improvement. And if I can hide it and a bunch of the harness while I'm at it, another improvement. But if you want yours under the hood - go for it.

gofastwclass

iTrader: (2)

The GM PCM's were designed for the under hood environment they live in. These things have a very low failure rate in factory trim. I see no reason to do additional work during a build protect the PCM from the environment it was designed to live in.

If you want an ultra clean, minimalist look - I completely understand doing all sorts of wacky stuff. I've built show only cars in the past and we would hide wires, components and electronics all for the sake of a specific look.

I'm not suggesting leaving a tangled mess of poorly routed OEM harness everywhere. I always clean up the harness and move things for a better flow. I'm just talking about the logic of moving a PCM (especially a P01 or P59 which are large) to the limited interior space of most swaps.

DT69cam

Did you use the GMPP harness ?? This is exactly where I wanted to install my harness in my 69 Camaro. I was hoping I did not have to modify the GMPP harness in order for the ECM to fit by the battery.

alocker

iTrader: (10)

Don't hack the firewall if you don't have too. If you don't have a harness yet get extra length and there is usually room to run the harness thought the fender and mount behind the headlights. There are usually extra holes where you can run bolts right through the ecm no bracket needed.

SS69LS1

iTrader: (108)

I ran the ecm on the inner fender when I had the LS1 in my 69. When I changed motors & subframe, I had a harness made and mounted the E38 above the glove box. Just where I wanted to put it. I definitely don't have a show car. I autocross it almost monthly and drove it from FL to NJ & back last year. The guy I'm building a camaro for now wants a clean firewall. No one way or the other is "wacky". The original poster asked where everyone was putting their ecm. We are just giving him options. With the GM performance harness, you are likely limited to somewhere under the hood in most cars.

Michael Yount

iTrader: (1)

This.

The harness often drives location --- and many aftermarket harnesses (all the ones I shopped...) are designed to have the extra length needed to mount the ecu inside. So, if your harness or your desire lead you to mount under hood or inside the passenger compartment --- go for it. I simply put the GM component in the same location that the Ford component lived before the GM, and where the Volvo component lived before the Ford component.

Nonetheless, even though they may be designed for a harsher environment, anytime an electrical component is able to be located in a place where heat, moisture and vibration are reduced -- you're making it easier on the component.

robm-951

iTrader: (6)

no, I lengthened a factory f-body harness. With a stock length harness, I think you will be limited to pretty close to the rear passenger side head. Either somewhere inside or under the rear of the passenger fender. I have no experience with the GMPP harness.

L92 OLDS

This ^^

Moving the ECU to the inside of the vehicle for the sole purpose of keeping it dry and cool make no sense. GM designed and validated them in the lab to withstand hi temps and moisture from the elements.

Hiding the ECU in a fender or in the interior of the car is a nice way to clean up the engine bay but my I would rather not dork up the IP wiring harness, cobble the are under my instrument panel or cut holes in my firewall for more harness grommets. The simplest method is to keep the ECU under the hood near the engine.

DT69cam

Thanks everyone for the replies. I appreciate the info.

01cherryreds10

iTrader: (9)

If you have a 411 or similar case pcm, use an s10 pcm mount. I bought one on ebay for like 10 bucks and it mounts to a flat surface and has a couple bolt holes as well as a hold down clip.

Wish I had a picture but mine is under the passenger side carpet pretty much where the passenger puts their feet. The harness has another couple of feet of room where I could of put it in the glove box but at the time I didn't want to ruin the glove box space. So after not using the glove box in the 5 years since I finished the swap, shoulda put it there, lol.

Also these ecms are weatherproof. They've got rubber seals on the case halfs to protect from the elements.

68conv455

I have the GMPP harness in a 68 A-body and I thought the length fits just right for mounting in the front of the passenger fender. I made a bracket to mount the fuse box on the front edge of the inner fender with the ecm and transmission controller on another bracket tucked in front of the inner fender next to the side marker light.

samckitt

iTrader: (5)

68conv455 above, sounds like I mounted mine similar to his. I made a bracket for the PCM (behind overflow on passenger side), & fuse box on right side.