I am just getting to the test phases of my wiring for the swap with the lt1. I dont appear to be getting a fuel pump signal from the pcm. I hooked a VOM to both wires from the computer and I am getting nothing. I realized i need to get some +ign power to the pink wire for the lt injectors etc so i will add that tomorrow but would that prevent the computer from telling the pump to turn on? Any thoughts or suggestions would be appreciated as always..

 

The pump should prime the pump when the key sends the first IGN pulse regardless of anything being wrong

Id recheck the wiring before continuing. VATS will kill fuel if not removed from the PCM, but it wont stop the initial prime from the pump that you're not getting

Make sure you ran the relay correctly with the PCM call side on the 12v leg, not the ground leg like most relays use. If thats still good, recheck your powers and grounds from the PCM and relay

 

Here's how the relay should be hooked up



and here's where it is on the C220 connector (the white one) on the LT1 harness

 

pocket, his car doesnt have vats, iv been down trying to help him on this aswell this week but i cant really help him.

 

LT1s all came with VATS which must be tuned out to run. My point was, even with the code still enabled in the tune, the engine should briefly fire before stalling out from no fuel. Hes got nothing, so the problem must be elsewhere

If he has a scanner available for his ALDL, it should throw a code related to VATS if its still active. It should throw a code anyways because it wont start and would be a good place to start looking

 

1. Check all power and ground wires to the pcm. Either check at the near/at the pcm connectors or the harness connectors.
2. Disconnect pcm from pcm connectors and measure resistance of pin that the fuel pump relay signal would be on to the pin on the harness connector and make sure its about zero ohms. If no resistance, then wire isn't connected somewhere inbetween.
3. Still no signal out then maybe bad pcm. A bad pcm will sometimes turn on the fans off the car with key on if it had a programming error. But could be completely dead too.
http://shbox.com/1/1995_pcm_conn_a.jpg
http://shbox.com/1/1995_pcm_conn_b.jpg
http://shbox.com/1/1995_pcm_conn_c.jpg
http://shbox.com/1/1995_pcm_conn_d.jpg

http://shbox.com/1/harness_connector_faces.htm

 

Thanks for all the direction guys! I contacted the pcm tuner and verified he tuned out vats. Since he was able to tune the computer doesnt that sort of automatically rule it out as bad? I havent been able to get out to the garage since I put this up but should hopefully be there tomorrow. Once I get a chance to play with everything I will let you know what I find. I am sure I have the correct wires from the PCM. I opened the connector and traced it back to the pin source. When I connect the IGN+ wire to the pink IGN+ in the LT1 circuit and energize it, the injectors all open. Is this normal? I havent attempted turning the motor yet as I dont have accessories on. I am waiting on my electric water pump to arrive tomorrow as well as my a/c bypass pulley. Anyways I should be able to get something accomplished tomorrow.

 

I got everything working finally! Im reading a prime signal as well as a run signal from the computer. I still dont have a working fuel relay circuit though. I think either I have a bad connection with the wires feeding into the relay connector or a bad relay. I bought new relays today to hook up the fuel pump and the new electric water pump I just installed. THANKS AGAIN FOR ALL THE HELP!! Thanks a million as always to Pocket.