View Full Version : Car Won't Start, Fuel Delivery - PSI Harness
Vicinity
10-06-2012, 08:13 AM
Ok, I got a PSI harness and tuned computer on an LS1. I have a sumped tank with a brand new fuel pump.
A few days ago I attempted to start the car and a fuel line burst, so I replaced the line. I bumped my hand on the fuel pump ground and pulled the wires apart. I regrounded it (the pump is grounded directly to the battery).
Since the IGN and FUEL relays are the same, I tried swapping them, nothing. Also, for ****s and giggles, I ran a noid light on the Injectors, no light.
I confirmed every ground on the car, I checked power to the EFI fuse box. It's all good (12v bat and 12v switched). I cranked and checked to see if there was 12v going to the fuel pump, it's a no go.
Is it possible for 2 new relays to go bad at the same time? I've checked absolutely everything I can think of... I've searched ls1tech and pro touring for the past 4 hours, I can't find anything.
Maybe it's my computer? The packaging it came in was badly damaged, but I figured they were supposed to be able to take a beating...
David Pozzi
10-06-2012, 02:53 PM
Does it have a MIL (Malfunction Indicator Light)?
It should come on when the ECM has power but engine isn't running. It would indicate the ECM is getting power.
I had a no start issue and found a wire pulled out from a terminal inside the fuse box. This was on a GM Performance Parts harness. I would suspect a wiring issue first.
gak68
10-06-2012, 03:04 PM
I know older chevy check engine lights blinked twice when you first switch the key on to tell you the computer is functioning properly. Does the fuel pump have an initial 3 second prime? have you confirmed the fuel pump still works by running a jumper wire to it? Do you hear the relays click on? Just some simple things to try, I had the same issue with an older chevy truck ended up being there was a loose connection in the tank at the pump it would randomly make the fuel pump cut out.
Vicinity
10-06-2012, 03:45 PM
Does it have a MIL (Malfunction Indicator Light)?
It should come on when the ECM has power but engine isn't running. It would indicate the ECM is getting power.
I had a no start issue and found a wire pulled out from a terminal inside the fuse box. This was on a GM Performance Parts harness. I would suspect a wiring issue first.
I got no light. So that means the PCM isn't getting power/malfunction?
David Pozzi
10-06-2012, 09:19 PM
Yes, I'd check for power in, and a good ground connection to the ECM.
Vicinity
10-07-2012, 05:13 AM
The ground is good, it's the same one I grounded the block with. The power should be good, AAW has an accessory pigtail with IGN and BAT (switched and always on power), I used one of the BAT terminals.
Vicinity
10-07-2012, 06:41 AM
Got it. Jon from PSI saw my thread on LS1tech and told me to call him. We got it sorted out, he told me to check a few things and I found a lose ground cabin side. So it was a ground, I just should have looked at the wires, and not the actual ground. Thanks David!
Cool. Looking forward to your updates on the ls1.
CarlC
10-08-2012, 08:26 AM
If memory serves the MIL output from the ECM is ground, not positive. The MIL light should come on with initial key-on.
It should also stay on after engine firing until a crankshaft relearn is performed.
Vicinity
10-08-2012, 11:54 AM
If memory serves the MIL output from the ECM is ground, not positive. The MIL light should come on with initial key-on.
It should also stay on after engine firing until a crankshaft relearn is performed.
I believe it didn't turn on because of the ground being lose on the firewall. I just went to Radio Shack and bought a dedicated MIL LED, so I'll be testing to confirm.
When I checked when I made this thread, I was using my high beam indicator light.
CarlC
10-08-2012, 12:54 PM
But if the ECM output is also ground, then the bulb has two grounds and no +. Some of the ECM triggered outputs (fans, MIL) are ground, not +. Hence, you may have to connect your high-beam to BAT+.
The MIL light should come on with the key in the IGN position but the engine not yet started.
Vicinity
10-08-2012, 01:04 PM
Oh, yeah, I know. The instructions had big bold letters saying "MIL GROUND OUTPUT". The ECM wasn't receiving a complete circuit, it was getting 12v but the cabin side ground was lose and wasn't flowing. I pulled the Hi beam light and left the positive, and just put my high beams on for the 12v.
Vicinity
10-08-2012, 02:45 PM
Yep, fuel pump primed and MIL stayed on. I didn't crank it to see if it turned off, my cooling setup isn't complete. I ran it once without coolant for 1 minute (exactly) to test if the engine worked.
Also, on a lighter note, I'm super excited now that I have a working engine. I might actually get to use my car.
Powered by vBulletin®