Ecm wiring through fire wall?

[Omgbigdeal]

I have a 1979 trans am getting an ls2. My question is my wire harness was made to run inside the car. It is on the passenger side it says to cut a 2" hole to run the wires. I may be blind but I'm having a hard time locating a good spot to run the harness. Does anyone have any insight ?


teroy

[amargari]

You can hide it by putting the hole in the side of the trans tunnel

[408maro]

That's a good idea. I wish I would have done that mines not so clean but works...
I just made a hole on the firewall.

https://static1.pt-content.com/images/pt/2017/03/20161218_155315_zpsrj6or4os-1.jpg (http://s296.photobucket.com/user/408maro1/media/20161218_155315_zpsrj6or4os.jpg.html)

https://static1.pt-content.com/images/pt/2017/03/20161221_135712_zpsbjqnnvjk-1.jpg (http://s296.photobucket.com/user/408maro1/media/20161221_135712_zpsbjqnnvjk.jpg.html)

[Omgbigdeal]

Good ideas I'm gonna look into the tunnel spot I suppose the ecm can be hidden under the dash als. Any pictures of the tunnel hole?

[raustinss]

Hell of a lot of work and not sure what your budget is but some guys have cut the harness and added a mil spec connector

[Build-It-Break-It]

I found some mil spec type connectors I'm going to run on my car. Better price and uses a "standard" style crimper. http://paradiseracing.com/?post_type=product&s=Bulkhead

[raustinss]

Yeah just like those ...run one in the tranny tunnel and then whenever you need to do work ...ie detail engine bay, swap motor etc the harness is a easily removed

[DT69Cam]

I would also like to use a bulkhead connector for my GMPP harness which hasn't arrived yet. Which connector have you guys used ??? How many pins are needed ?? I heard that cutting the harness will cause problems with the ECM ?? Anyone know if this is actually true ???

[dontlifttoshift]

It will only damage the ecm if you screw it up. I was using the the Molex XRC 31 pin connectors but have switched over to the Delphi HES 47 pin connectors. Mouser and Waytek have both. I spent a boatload of money on crimpers, though.

[Twentyover]

It will only damage the ecm if you screw it up. I was using the the Molex XRC 31 pin connectors but have switched over to the Delphi HES 47 pin connectors. Mouser and Waytek have both. I spent a boatload of money on crimpers, though.

Why did you switch from the Molex to Delphi? What kind of crimpers are you using? Thanks- I'm about ready to start wiring an old OBD1 system, probably switching to Megasquirt

[amargari]

Good ideas I'm gonna look into the tunnel spot I suppose the ecm can be hidden under the dash als. Any pictures of the tunnel hole?

Sorry, I looked through my site and I don't have clear pictures. It was on the left side near the firewall at about the 2:00 position if you think of the tunnel as a clock with 12:00 top dead center.

[dontlifttoshift]

Why did you switch from the Molex to Delphi? What kind of crimpers are you using? Thanks- I'm about ready to start wiring an old OBD1 system, probably switching to Megasquirt

The Molex really only come in one size, the Delphi has several options. Also, the 47 pin means getting a LS harness in 2 connectors instead of three. There wasn't a huge difference in money between the two but the Delphi gives us more options. Some sizes can carry 12 ga wire and 40 amps.

I have the Molex branded crimper and bought a Rennsteig and several die sets to do the Delphi.....all from Waytek. If you are careful they both can be crimped with weather pack style, non ratcheting, one step at a time crimpers. We do enough of these that it wasn't worth the time to not have the right crimpers.

[Twentyover]

Thanks dontlift.

I'll take a look at Wytek's catalog and see what I can afford. I like the ideaof being able to unscrew a single conector or two and being able to take the entire engine wiring harness out with the engine, not needing to jack around with 20 separate connections