I cut a hole big enough to slide the pcm connectors through.
But there is no grommet big enough (that I can find) to seal it up.

Did you make some kind of 2-piece cover plate to go over the hole?

Fill it with putty?

Some other solution?


(it took a pretty good size hole to get a pcm connector (and the wire bundle on top of the connector) to go through)

Maybe everybody else just pushed all the small stuff through from the inside of the car, instead of pushing the big stuff through from the engine bay side...?

Our pcm is still in the engine compartment, but for other holes in the firewall (heater core, some hole on the driver's side) we've covered them with aluminum sheets and either used sheet metal screws or pop rivets to keep it in place.

Jason

I didn't do it your way....the hole thing that is.....but what I did for a couple of large holes I drilled to stick my remote resevior shock canisters through the rear firewall was to cut a approx. 4" aluminum disc with a big hole saw....then cut out the center just bigger than the line that went through there and then cut a slot from the edge of the disc to the center so I could bend it over/around the line....then I used some heavy rubber I found at Orchard Supply and cut it the same size as the 4" disc and made it TIGHT to the line and cut a slot in that too and screwed them together onto the fire wall...here is a pic....

I've been kicking around 2 approaches.

The first one is a plate similar to that, but with the hole in the center. And with a second plate just like it, but rotate it so the slots don't align. I'd need to put a piece of hose (probably small radiator hose) around the wires, zip-tied or hose clamped so the wire bundles become mostly round and I get a good seal. Matching the hole size to the clamped size of the hose/wire combo. The slots could be smaller than the hole, since I only have to slip one wire bundle in at a time.

The other thought is to use a piece of scrap 1/2" delrin I have laying around. Make the hole first. Then cut out a large "keystone", like from the top center of an arch. Drop the wires (wrapped in a hose) then put the keystone back on top. The keystone would have a couple of ears so I could bolt it to the top of the main piece. (it would look kind of like a stocky T with a narrow base and a wide top) The 1/2" material would support the wires better than aluminum plate.

Trying not to over-engineer it, but not wanting to set myself up for problems with the install either... I'm bringing the two main pcm bundles, the 3 smaller bundles, and the starter and alternator wires all through the same hole, between the heater opening and the passenger side cylinder head.

I used a grommet from the door. It is large enough for the connectors to fit through. I just trimmed it up so it didn't have the long extra part that originally stretched between the door and the firewall.

It worked perfect.

For my Painless harness, the existing hole to the outside of the HVAC panel was larger enough to fish the ECM connectors through. Not sure if the stock set-up is fatter than the Painless.

I then put all the wiring into that plastic convuluted sheathing to encapsulate it. Then I split some fuel line and lined the edge of the firewall. To further reduce chaffing, I placed big zip ties on either side of and against the firewall to keep movement minimized.

I think I tried that right-most hole and couldn't get them to go through it. (that, or the wires weren't long enough so I moved past that option)

Good idea on lining the edge... If I use aluminum plate I'll put it inside the hole after the plates are rotated.





hmmm... I like reusing parts like that. Since I won't have any wires passing into the doors anymore, that could be an option. Just have to seal off the hole that's left.

Just curious why you are moving the PCM inside? I know it's in the way if you want to run the cage to the strut tower?

Clean up the engine compartment......less heat.....room for cage up front.....

No nice cage in the works just yet...

It's a carry-over project from back in the winter when I was waiting on money for the engine replacement. Moving (or removing) whatever was forward of the firewall, and especially anything forward of the front wheels. (including fuseblocks, abs, battery, etc.)

I didn't realize how big a job I still had left to finish the wiring though. I spent probably 2 days on it this past weekend, and still looking at 3-5 hours to finish it up, including mounting everything somewhere so it's not flopping around...

Can you post some pictures when you are done?

Sure will.

May be a couple weeks before I get it wrapped up though...

Good advice from all - the only thing I can add is that I would run the high current stuff - starter/alt/bat+ thru a separate passthru. If you have a short and melt a big wire you don't want it to take out the PCM harness too.

Good point. It didn't seem quite right to have them all together, but I couldn't come up with any good reason to separate them. That's a real good reason.

Go to www.holley.com and search for "firewall grommett"

....those are purdy!

I think I have seen them, or some like them, before.....they are not expensive as I remember, but not as cheap as my solution either....if I was a "serious" racer.....I would use them...

Advertised at $15-25

Made for steel braided hose penetrations.

yup....like I said...not unreasonable....

I just finished the same project (moving fuse panels,PCM inside) It took for ever, but now I can say I know where every single wire goes, and and I elliminated every piece of wire that I don't need. As to WHY? Well, it is free, and I think I got too much time on my hands...

Where did you put your fuse boxes, PCM?
Mine are sitting where the glove box used to be.

PCM is mounted INSIDE the glovebox....Underhood electrical center is on floor below the glovebox...

PCM will probably be on the hump, behind the dash where the radio used to be. I still have the heater part of the hvac. The pcm will be in the path of the heat, if I put it on the hump, but it won't be any hotter than it was under the hood... It will fit under the cowl (on the inside of the car) where the fresh air intake fed the hvac blower. There would still be about an inch of open space left above the blower intake. It's more out of the way there, but harder to reach when the dash and glove compartment are back in place.

I'm still toying with a couple of ideas on the UEC.

Most likely the lightweight battery will be in the low spot where the passenger back seat used to be. Then the UEC will end up in the console, with a short hot cable to it, and some longer medium gauge wires from it to the dash fuseblock and ignition switch on the column. Or the UEC will end up under the dash somewhere, with a longer hot cable to it (which will be needed anyway if/when I install an outside cutoff switch) and then shorter hot wires running from it to the dash fuseblock and switch.

I mounted the PCM to the floorboard right as it turned up.

I mounted the fues box in the glove box hole.