Just wondering if anyone had put their pcm here (see photos below)? I am thinking that I'll need a heat/splash shield to protect it from any spray/debris from the serp belt. I know the pcm can live under the hood, in the 4th gen it live right where my HVAC system sits, so that shouldn't be too much of a problem.

The reason I even thoought to put it here is that I was going to put it in the spot where the evap canister was (the battery location on Camaros). However, when we laid the wire harness on the motor the harness reached all the way up to the coolant tank (amazingly!!!), so I said "What if????".

So, anyone done this or will this cause me unimaginable headaches. BTW, this also eliminates the need to do ~90 wire extentions, 180 splices in total, which will cut down on labor time dramatically.

 

I got mine to fit in the stock location with a stock length painless harness

 

I'm using the stock ls1 harness and will be adding in the needed 3rd gen wires/connectors as needed. The stock fender pass through only has 40 something wires going through it, so the close to 90 wires needed for the pcm don't have a weather-proof way to get to the stock location, otherwise that's where I'd put it.

 

I fabricated a new grommet to seal it up, did some other changes to make it look right. to be honest , I have seen a few ecm's mounted where you did yours and i think it would be more in the way then anything.

 

If you've the right tools the splicing really isn't all that bad once you get into it.



I like this option much better, though obviously still not done.
ECM is going behind the dash:

 

Well, where I have it shown is hardly permanent, it was just set on the inner fender 'rail'. I'd like to get the pcm inside, what did you make the grommet of?? Or is there somewhere where you can get them.
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what kind of 3800 is that?? a n/a, supercharged or turbo??

 

Stock from an 02 Camaro.
Got it cheap from a guy that wrecked his car.

 

Cheap is good

 

they sure charge alot for harnesses don't they. i put mine under the dash as well.

 

Another vote for under the dash. I had mine pretty close to where you are talking about but more up on the fender. Looked horrible, best to take you time and do it right. Check this thread for pics where I put mine..


edit, well everytime I post a link to the thread it breaks it so here's a copy and paste from that post. (Will my PCM bake this close to the header?? )

Here are some pics I took of where I mounted mine.. It definitely looks much better with the PCM inside and hidden away.

 

I kept mine in close proximity to OE. I used a 3/4" square tube that bolts to the non-AC heater box and strut tower. The wires come close to the headers, but not close enough to melt anything.

 

make a hole under the HVAC box over the "framerail" area... pass the PCM connectors thru, and put a weathertight grommet on it.

that'll let you mount it under the dash, and have a nice clean looking install.

 

Ok guys, you've convinced me to put it inside. Did you need to lengthen all the wires for it to reach under the dash like that??

Where's a good place to get a weathertight grommet?? Would any auto parts stores have them?? Its all these little things that keep tripping me up!!

 

you dont need to extend any of the LS1 harness wires.
you may want to extend other wires from your thirdgen harness to the LS1. harness.... but overall, theres not much extending.
there is alot of shortening of the stock thirdgen stuff...

i found a ton of grommets at my local hydraulic supply store.

 

thanks, I was hoping that going under the dash wouldn't require extending the harness. I figured there would be some extending of the 3rd gen harness, but there's far less of that than the 4th gen harness.

I'll have to see if I can find a hydraulic supply store around here, none spring to mind.

 

Mine has worked for over 3k miles so far including sitting through the 101 traffic jams in the san fernando valley here in Los Angeles (100+ degree weather). works fine...

 

Glad to see that you made it work! Where you have it is a little farther away from the headers and is probably ok. What are you using for an overflow tank since the pcm is sitting there??

I see that you put the battery on the pass side, why did you do that? Using a camaro harness?

EDIT: Could you take some close ups of how the pcm is mounted to the strut tower?

 

I had to cut the washer pump off of my windshield wiper motor to fit in my car. My car is an '84 model and it has a different style winshield wiper motor/ washer pump. (I think they switched styles in '87) Since I wasn't using the washer motor it allowed me to easily convert my washer fluid tank into a radiator overflow tank. I drilled and glued a fitting into the bottom of the tank and it works fine.

As for the battery that is the factory location for my model year car.

I'll get some pics in a bit of the mounting but to describe it I just found the flattest spot on the fender and drilled 3 holes and used rubber grommets/ washers to give a little vibration absorbtion when I mounted the black plastic pcm holder.

 

Cool, I didn't realize the battery location was changed side to side in the Firebirds. Guess thats my thing to learn for the day .

Hmm, I don't have a pcm holder, just the pcm/harness. Any shots of that would help too if you could. Thanks a lot.

 

I DOING A 94 LT1 SWAP INTO A 86 IROC CAN I JUST GET RID OF 86 ECM WHICH IS ON RIGHT SIDE UNDER DASH REPLACE IT WITH 94 ECM AND RUN 94 ECM WIRE THROUGH FIREWALL WHERE THE 86 ECM WENT THROUGH

 

No. The LT1 PCM is too big and the stock wiring isn't long enough.


...stop yelling at me

 

The LT1 PCM will fit under the dash. I had to extend my wires.

 

don't mind my dad, I let him use my account... He's not the best @ internet speak.

 

there is room under the dash for the ECM the 94 vette harness is not long enought to reach under the dash unless I extend the wires and Bingo did you have put a hole in firewall ?and where and evey one thanks for your help

 

Bingo,
You got the LT1 PCM to fit where the third gen ECM was mounted?

 

I slid mine in the same place as my factory one. It is held in place by the underdash panel. It has been there for three years. I extended 70 something wires so I could run it through the factory opening behind the kick panel.

 

how big hole did you need 21/2 inch? I dont know which way is best to run the PcM wire to put it the factory way the right front fender has to come off plus ground effects right?? I way seen a lot easyer

 

The fender doesn't have to come off but, the inner fender liner has to come out. I ran mine through the factory hole because it made sense to me. I used a factory bulkhead grommet I pulled from another harness. I built my harness off the car using a spare harness as a length guide. I didn't cut any of my factory wires. I plan on pulling my harness soon to rewrap it soon. I will try to get pics.

 

I put the 21/8 inch hole above the frame rails now to find a grommet that size and I am still extending a few more wires