PCM OK or not
PCM OK or not Hello to all my ls1techies. my setup is a 1971 c10, lq4/th400 with cam, springs, and head upgrade, stock dbw harness. I'm trying to complete the wiring, see if my pcm works, and check my wiring/soldering for continuity. I needed to extend the drive side coil and injector wires (they are not connected). to check if the pcm is operational, I wired the fuel pump relay to see if the fuel system will prime. the relay clicked, but did not pressurize the system. the fuel pump relay signal does turn on my test light for 2 seconds & thens turn off. the fuel pump never primes the fuel lines. questions. would the antitheft pcm feature keep the engine from priming fuel system, cranking and running? is the pcm awaiting the signals of all the connectors such as MAP sensor, coils, Injectors, knock, crank sensor etc. to prime the system. any help I will appreciate it thanks. clark.
If the pump relay control wire lights up for 2 seconds then goes off, I'd say the PCM is working. It can't stop the pump from working if its turning the relay circuit on. Something on the pump side of the circuit is wrong if the pump does not prime.
The VATS only disables fuel injectors, not the pump. Everything else should still work. You may get it to fire for a short time without disabling VATS (usually 2 seconds).
The VATS only disables fuel injectors, not the pump. Everything else should still work. You may get it to fire for a short time without disabling VATS (usually 2 seconds).
thanks ls1nova71 and i r teh noobz for your replies. just to update you, I completed all my wiring (extending the driver side coil and injectors). I also rewired my fuel pump relay. the engine coughed for 2 seconds, each time around but never completely ran. this means that I will need a pcm with the vats removed. I bet that will fix my problem. yeah, I know, I should've done that first. I'm sorry. I have so much stuff laying around that sometimes I forget what I have. somehow I thought I had dbw pcm with the vats removed. thanks again for your help. clark.
lt1swap.com will do a VATS/emissions delete for 75 bucks. I used them for my initial tune/emissions delete. No issues at all.
You may be able to get the engine to stay running for a short time with brake wash or starting fluid. Just be careful as it can backfire quite violently if the conditions are right.
You may be able to get the engine to stay running for a short time with brake wash or starting fluid. Just be careful as it can backfire quite violently if the conditions are right.
Thanks I r teh noobz. The brake cleaner thing won't work for me. I am very impatient. I wanted it to work so that I could drive around the block a few times. I'll order my PCM on Monday. And thanks again, Clark .
