ECM Wiring Harness Swap - How far to go?
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Car: 91 Bird
Engine: TPI 350
Transmission: 5-Speed
Axle/Gears: 2.77 posi
ECM Wiring Harness Swap - How far to go?
I did a search but it didn't address the question I have. The extent of the wiring harness to change. Below are my guesses. Heres the parts list...
Outside:
1) ECM harness from the firewall to the engine. (Yes)
2) "Body" harness from driver side firewall to frontend. (No)
Inside:
3) ECM to the firewall (other part of #1 above) (?)
4) ECM to the rest of the under dash stuff (?)
5) The rest of the under dash stuff and along with it the rest of the body. Plugs in about a foot from the ECM. (hope not)
Here might be the catch. 1990 Iroc 350 TPI Auto into a 1991 Firebird 305 TBI T5 and am keeping the T5.
I have the complete donor including auto, wiring, rearend, and suspension.
Thanks, next weekend I hope to start. The engine is running perfect now.
Outside:
1) ECM harness from the firewall to the engine. (Yes)
2) "Body" harness from driver side firewall to frontend. (No)
Inside:
3) ECM to the firewall (other part of #1 above) (?)
4) ECM to the rest of the under dash stuff (?)
5) The rest of the under dash stuff and along with it the rest of the body. Plugs in about a foot from the ECM. (hope not)
Here might be the catch. 1990 Iroc 350 TPI Auto into a 1991 Firebird 305 TBI T5 and am keeping the T5.
I have the complete donor including auto, wiring, rearend, and suspension.
Thanks, next weekend I hope to start. The engine is running perfect now.
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Car: 82 Berlinetta/57 Bel Air
Engine: LS1/LQ4
Transmission: 4L60E/4L80E
Axle/Gears: 12B-3.73/9"-3.89
1) & 2) correct.
3) Change.
4) No change needed.
5) No change needed.
You'll have an unused portion of the tranny harness, the 4-prong square.
3) Change.
4) No change needed.
5) No change needed.
You'll have an unused portion of the tranny harness, the 4-prong square.
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Car: 91 Bird
Engine: TPI 350
Transmission: 5-Speed
Axle/Gears: 2.77 posi
Re: ECM Wiring Harness Swap - How far to go?
Well, I guess I can't complain. I just turned 44 today. I unhooked the battery and went inside. That's a good start.
Not really the age, just burnt out right now. Working two jobs, 6 yr old and 5 mth old kids, oh, don't forget the wife.
Not really the age, just burnt out right now. Working two jobs, 6 yr old and 5 mth old kids, oh, don't forget the wife.
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Car: 82 Berlinetta/57 Bel Air
Engine: LS1/LQ4
Transmission: 4L60E/4L80E
Axle/Gears: 12B-3.73/9"-3.89
I hear ya. I remember the first time I saw a 3rd gen for less than $8000 - that was about $7950 more than I could afford at the time. . .
Oh, and Happy Birthday!
Oh, and Happy Birthday!
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Car: 87 Iroc convertible
Engine: 305 TPI
Transmission: t5
Re: ECM Wiring Harness Swap - How far to go?
I've been searching to figure out if I can use my 87 305 TPI wiring harness for my 89 350 TPI engine swap without posting my own question. I guess I'm asking about the #1 question asked by FNFAL308.
Thanks
Thanks
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#8
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Car: 82 Berlinetta/57 Bel Air
Engine: LS1/LQ4
Transmission: 4L60E/4L80E
Axle/Gears: 12B-3.73/9"-3.89
'89 didn't have the cold start injector. I'm not sure if that drove pin-out changes, or you'll just have a connector that doesn't go anywhere.
Better to ask on the TPI forum.
Better to ask on the TPI forum.
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Car: 89 Camaro, 00Xtreme s-10, 89 Buick "Party Ave"
Engine: 305tbi
Transmission: 700r
Re: ECM Wiring Harness Swap - How far to go?
I know we're talking about swapping a 305tbi to a 350tpi here...but does the same hold true for swaping a v6 to v8 as far as the wiring harness swaps go??...are the interior(fuse pannel)wiring the same for all 3rd gens..am I thinking corectly that only the engine wiring harness changed??
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Car: 82 Berlinetta/57 Bel Air
Engine: LS1/LQ4
Transmission: 4L60E/4L80E
Axle/Gears: 12B-3.73/9"-3.89
Things like digital vs. analog dash, VATS or no VATS, carb'd vs. EFI, etc., changed from year to year, and from 'Bird to Camaro of the same year.
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Car: 91 Bird
Engine: TPI 350
Transmission: 5-Speed
Axle/Gears: 2.77 posi
Re: ECM Wiring Harness Swap - How far to go?
Came back around to this post again. Started pulling the wiring this morning for the swap. Again, Donor = 1989 IROC 350 TPI, going into 1991 Firebird 305 TBI.
Man it's a lot of wires. It would be easier if I could just undo the connection at the firewall and the ecm connector and swap all the under hood stuff over. But I don't think that will happen.
What was everyone's good way of separating the ECM wiring from the body/basic engine stuff? Strip all the wire covers?
About (not looking for exact numbers) how many wires will I have to splice back into the 91 basic engine/body stuff? Meaning how many are shared?
Will there be a noticeable separation between the majority of the wires?
There are two conectors on the back of the ecm and one white one that connects to something under the dash. Is the white one part of the ecm loom or can I separate it out too.
Man it's a lot of wires. It would be easier if I could just undo the connection at the firewall and the ecm connector and swap all the under hood stuff over. But I don't think that will happen.
What was everyone's good way of separating the ECM wiring from the body/basic engine stuff? Strip all the wire covers?
About (not looking for exact numbers) how many wires will I have to splice back into the 91 basic engine/body stuff? Meaning how many are shared?
Will there be a noticeable separation between the majority of the wires?
There are two conectors on the back of the ecm and one white one that connects to something under the dash. Is the white one part of the ecm loom or can I separate it out too.
#12
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Re: ECM Wiring Harness Swap - How far to go?
It would be easier if I could just undo the connection at the firewall and the ecm connector and swap all the under hood stuff over.
The 89 and 91 harnesses are pretty similar. The one pair of wires I know you will not have and will need on the 89 harness is the electric speedo sending unit for the tranny. ( 89 Camaro was cable and 91 Firebird was electric ) Your BEST BET is to get the wiring schematic for the 89 IROC and the 91 Bird that your harness came from and match the wiring up. Since the Firebird headlight harness is different than the camaro style - you will want to keep that in place and intact.
Trying to rip open the harness to pick and choose what wires to keep is a fools errand. Get the C100 diagrams and make comparisons - that way you can simply add any additional wiring you might need.
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Car: 91 Bird
Engine: TPI 350
Transmission: 5-Speed
Axle/Gears: 2.77 posi
Re: ECM Wiring Harness Swap - How far to go?
Just got thru pulling all the wiring. I see what you are saying now - athough I didn't think about the speedo even though I was looking at the mechanical one when undoing the 700r4 wires. Crap. Had a short in the speedo anyway.
The A/C wiring is separate. The body wiring is separate.
The only other issue is the windshield wipers and starting circuits still in the motor loom which I'm betting/hoping is the same at the firewall connector.
On the speedo I'll have to find where the wires are supposed to come out of the connector and hope they are not in the donor wires coming out for something else. If they are empty, I'll transfer the prongs (or whatever) from the 91 to the 89 plug and plug it in to the 91 firewall. So, I may have to move/run some wires but most likely not many.
Now I just need to get a wiring diagram of an 89 and 91 and a bottle of good scotch. I'll be all set to pull all of my gray hair out.
The A/C wiring is separate. The body wiring is separate.
The only other issue is the windshield wipers and starting circuits still in the motor loom which I'm betting/hoping is the same at the firewall connector.
On the speedo I'll have to find where the wires are supposed to come out of the connector and hope they are not in the donor wires coming out for something else. If they are empty, I'll transfer the prongs (or whatever) from the 91 to the 89 plug and plug it in to the 91 firewall. So, I may have to move/run some wires but most likely not many.
Now I just need to get a wiring diagram of an 89 and 91 and a bottle of good scotch. I'll be all set to pull all of my gray hair out.
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Re: ECM Wiring Harness Swap - How far to go?
anyone on here got a real picture of a 89 camaro wiring harness? I removed the a/c kept the heat....it is a L98 engine from a 89 formula put into a 87 camaro. I got ALOT
----------
anyone on here got a real picture of a 89 camaro wiring harness?
I removed the a/c kept the heat....it is a L98 engine from a 89 formula put into a 87 camaro.
I got ALOT of spare connections, can anyone help me out?
----------
anyone on here got a real picture of a 89 camaro wiring harness?
I removed the a/c kept the heat....it is a L98 engine from a 89 formula put into a 87 camaro.
I got ALOT of spare connections, can anyone help me out?
Last edited by john1784h@yahoo; 01-09-2008 at 11:08 PM. Reason: Automerged Doublepost
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Car: '90 Trans Am-12.45@110.71
Engine: 355 w/AFR 195's Elem. 400/430 HP/TQ
Transmission: Tremec T-56
Axle/Gears: 12 Bolt 3.73
Re: ECM Wiring Harness Swap - How far to go?
Save yourself a lot of grief and buy this guys harness:
https://www.thirdgen.org/forums/engi...tml?highlight=
https://www.thirdgen.org/forums/engi...tml?highlight=
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Car: '90 Trans Am-12.45@110.71
Engine: 355 w/AFR 195's Elem. 400/430 HP/TQ
Transmission: Tremec T-56
Axle/Gears: 12 Bolt 3.73
Re: ECM Wiring Harness Swap - How far to go?
Now I just need to get a wiring diagram of an 89 and 91 and a bottle of good scotch. I'll be all set to pull all of my gray hair out.
#21
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Car: 91 Bird
Engine: TPI 350
Transmission: 5-Speed
Axle/Gears: 2.77 posi
Re: ECM Wiring Harness Swap - How far to go?
As near as I can tell, that is for a MAP - 1989 was the last year for MAF - I think. He said he took it out of a 1990 and rewired it for a 1991. I am taking a MAF out of a 1989 IROC and putting the MAF in a 1991 Firebird. I am not changing to MAP.
But, I may be wrong about his being MAP, so I posted there.
But, I may be wrong about his being MAP, so I posted there.
#22
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Car: 91 Bird
Engine: TPI 350
Transmission: 5-Speed
Axle/Gears: 2.77 posi
Re: ECM Wiring Harness Swap - How far to go?
His is for a MAP.
Why would putting a MAF in my car not be a good idea? It has 305 TBI now, and I have a 350 MAF. So in goes the MAF. Sounds like a no brainer to me. If I had a MAP then in it would go.
Why would putting a MAF in my car not be a good idea? It has 305 TBI now, and I have a 350 MAF. So in goes the MAF. Sounds like a no brainer to me. If I had a MAP then in it would go.
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Car: subaru wagon, two formula's
Engine: tpi 350's
Transmission: 700 r4
Axle/Gears: 3.27 posi
Re: ECM Wiring Harness Swap - How far to go?
I know this is an old thread, I'm putting 89 tpi350 into 91tbi car, I don't understand why u have to do any rep inning, it's that white connector off the ECM wires to the 91's, that's holding me back. Can u guys help me?
#24
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Re: ECM Wiring Harness Swap - How far to go?
I don't understand why u have to do any rep inning,
All the wiring info you need for your swap can be found on these 2 webpages.
http://berlinetta.info/C100.htm
http://berlinetta.info/C207.htm
Good Luck with your conversion !
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