pulling my 305 how do i pull the wires from ecm and engine. i dont know how to get it off fire wall

anyone know?

 

Wrong board. Moved...

Your question is a bit vauge, but I'll take a stab at it...

If your pulling the engine, the harness can be left in place. But... if your going to carb, selling your EFI, or whatever, the harness can be removed more or less intact, at least on some of the cars Ive worked on. IIRC, there are differences thru the years.

I assume by firewall you mean the bulkhead connector next to the brake booster. There is a bolt in the center of the bulkhead connector. I dont recall what size it is, but once you unbolt it, the connector can be unplugged. Be aware that the harness cannot be entirely removed by simply unbolting the connector, at least in my experience. If you want to pull it out completly, you have to pull out the body related wiring from the main harness.

As for the ECM part. The ECM and other related wiring passes in behind the pass. side fender. There is a weathertight connection filled with epoxy that passes in behind the kick panel under the dash. Ideally, youll want to remove the fender to get at it.

 

im doing a tuned port 350 swap. can i use the same computer wiring but just get the computer? and with engine harness i will have to use the same one right? i need help im doing this in june and i need to make sure i know what im doing because i have to remove it on mine then go remove it my friends gta.

 

If your car currently has TPI, yes, the wiring can stay. Just disconnect the wire harness from the engine and put it aside. No need to remove it from the car. The ECM will work, but depending on what you have, you may want to get bigger injectors and do some prom burning to recalibrate/retune it for the 350. If its an unmolested L98, then stock L98 injectors and a stock L98 prom/memcal will be all you need to do.

If you have something other than TPI, then you'll want to grab it all. Engine, wiring, ECM, and any other misc. items that you may need to put it in your car.

 

the car im doing the swap on is a tbi. i know i need to replace the ecm and engine wiring harness. is there any other wires i have to replace ?

 

I'm no expert on TPI - but I don't think there's any need to remove or disturb the wiring on the driver side firewall - that should all be basic wiring for headlights, guages, power for the fuse box, etc. The swap will need to occur with the wiring on the pass side of the car - those wires run through the fenderwell - if you remove the plastic inner fender from the wheel well, you can see the pass harness and where it connects from engine bay to interior.

 

I think that varies from car to car. I know on mine, the wires for the headlights, window washer, tmep gauge, etc. had certain circuits spliced in with the engine harness. The connector on thefirewall had to be removed and those applicable wires taken out of the main harness, and put into my new SFI harness. I dont know if the TPI car, or the newer cars, have the harness set up in the same fashion or not.

Something to be aware of if your going to get the wires out. Its pretty easy to tell once you pull most of the engine harness out. IIRC, the fuel pump, power, and a few other circuits passed thru the connector at the firewall. If you have access to wiring diagrams, those can tell you. The chiltons f-body manual actually has complete reprints of the GM f-body wiring diagram manual (at least the last time I checked). Pick it up before you pull the engine. It will help a lot when splicing in the new harness.

As for the TPI swap. Thats about it. Youll need the main engine harness, ECM, and complete engine. There may also be other items that you want to grab. Just look both cars over and make a note of what each one has, and does not have.

 

i got a chiltons all ready and when i do the swap im just going to hook it up and see what works and doesnt work when i get it started it looks like an easy swap im taking 350 tpi from an 87 trans am and putting it in an 89 firebird