Ls1 c4 swap
05-13-2013, 03:23 PM
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Ls1 c4 swap Hello guys and gals, got my self into another project
i am in the process of puting an lsi into my 85 c4
so you most likley will see me asking for pointers many times
will be running the c5 factory ecm with stand alone harness
can anyone tell me how to make the c4 tach run off the ls1
or if i use a aftermarket tach how do you hook it up?
ALSO WHAT THROTTLE BODY SHOULD I USE TO CONVERT TO CABLE
My first stumble
/
i am in the process of puting an lsi into my 85 c4
so you most likley will see me asking for pointers many times
will be running the c5 factory ecm with stand alone harness
can anyone tell me how to make the c4 tach run off the ls1
or if i use a aftermarket tach how do you hook it up?
ALSO WHAT THROTTLE BODY SHOULD I USE TO CONVERT TO CABLE
My first stumble
/
Last edited by parriedog49; 05-13-2013 at 04:51 PM.
05-14-2013, 01:40 AM
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First, I have a c2 lsx swap and a 94 c4 lt1 car....and as far as I know the c4 had atleast two different tachs, maybe more if you include 84 since there were atleast 4 different pcms.
As for making the swap easy....not any c5 pcm will do....(easily). Use 99-04, and use the later tb. I think also 99 not sure. I ve used both. The early tb has a different lenght/ size wire cam swing assembly. I would use 99+ and a 99 -02 f body pcm. A stand alone harness makes it easy, but be sure about exactly which tps, iac, temp sender, maf/iat combo or seperated, fans etc ....that your using. Its cleaner to use the later maf with iat but if you want to go sd in the future...use the earlier maf with seperate iat. I dont know the pin on the pcm off hand, most of the harness makers make it a white wire for the tach signal...that is unterminated, like the fan wires, fp wire, and few others.
Remember that the fp wire is switched +, the fans are switched grounds all to relays. The c4 is a fabulous swap car...
As for making the swap easy....not any c5 pcm will do....(easily). Use 99-04, and use the later tb. I think also 99 not sure. I ve used both. The early tb has a different lenght/ size wire cam swing assembly. I would use 99+ and a 99 -02 f body pcm. A stand alone harness makes it easy, but be sure about exactly which tps, iac, temp sender, maf/iat combo or seperated, fans etc ....that your using. Its cleaner to use the later maf with iat but if you want to go sd in the future...use the earlier maf with seperate iat. I dont know the pin on the pcm off hand, most of the harness makers make it a white wire for the tach signal...that is unterminated, like the fan wires, fp wire, and few others.
Remember that the fp wire is switched +, the fans are switched grounds all to relays. The c4 is a fabulous swap car...
