Hello! I am wanting to change out my 3.1L SD engine from a 92 firebird and put in a 350 TPI unit. If I stay with the SD set up, can I keep my existing wiring harness and just add two injector plugs?

thanks

 

Ok. if the 350 TPI uses the 730 ECM and the 3.1L uses the same 730 ECM , and the only difference is the Memcal, then why wouldn't the wiring harness hook up the same way? I don't know what the difference would be between the SD 3.1L harness and a SD 350 TPI harness. TPI uses the same type of two coil connector like the 3.1L, I think, so the only difference would be the connections? the 3.1 has these:

oil pressure
coolant temp
fan control (only 1 fan instead of 2)
iac
tps
injectors (only six instead of 8)
a/c compressor
alternator
knock sensor
egr
MAP sensor
distributor
incoming air temp sensor
brake
tranny connector

wouldn't all of these be the same on the 350 tpi system?

 

I've done that same swap. The V6 harness won't work without lots of splicing and chopping. For one, the alt and the a/c compressor are on opposite sides, so you'd have to chop up the harness to switch them. I think the TPI air-injection pump is different too. I don't remember the other specifics, but I looked into using my V6 harness and found it would really be a hassel to convert it to the TPI config. You would be better off getting the real TPI harness.

 

Ok. I've gotten the wiring diagram from the chevythunder.com web site for the 350 TPI ECM, and Alex Altvater is going to give me the ones for the 3.1L ECM tomorrow. So, I should have a pretty good idea this weekend if I can really use the same harness or if I'll need another one.

thanks everyone for the information and help! I'll keep ya posted on what I find out. If anyone wants those diagrams, just email me at dalesimpson@insightbb.com.

dale

 

Yeah, let us know what you find out w/ those diagrams. I was given a swap over chart a while back, and the diagrams look pretty much the same. Change about 2-3 plugs, 2 more injector clips, and your good to go. I will be doing a swap in the upcoming winter hopefully...the info you find out would be much appreciated

 

Hey would you happen to still have those diagrams for the swap? Which connectors did you have to swap over? I've looked over the 3.1L wiring diagram in the haynes manual, and compared it to the wiring diagram for the 5.7L in the same book and they're not the same. The diagram in the book is not the same as the one I found on Chevy thunder.com either tho.. so I'm not sure which one is correct.

 

I'll post it on here so everyone could see. If it's wrong, let me know...from what I know though, the highlighted ones are the only differences...
Hope it helps!

 

i have modified the v6 harness fears ago but the car had no egr,smog controls,custom chip deleteing all smog and egr stuff,much easier to get the appropriate dash and harness.