Texcuda
I'm Awesome
My son has a 98 C1500 with the L31 vortec motor. The truck has 210k miles on it. He started having an intermittent issue where the engine will start then shut off after 1 - 2 seconds. Usually, he could cycle the key several times to get the truck to start, but a couple times he had to borrow his mother-in-law's vehicle because he couldn't get it to start at all.
He doesn't live terribly close so I couldn't do a normal diagnostic on it easily. We decided to go the hail mary route and ordered a new gm fuel pump assembly and the scpi to mpi conversion. With the mileage on the truck and the fact this is his daily driver, I figured it wouldn't be wasted money, and I assumed the issue would be one of these 2 things. We finally got it back together a couple hours ago and the truck will not stay running longer than 1 - 2 seconds. Here's the things I've tried so far:
Fuel Pressure Gauge on Schrader valve: 60 psi key on, engine off; while cranking the pressure drops into the low 50's
I thought we had a fueling issue and tried to keep the engine running by spraying carb cleaner and pouring gas down the throttle body (don't do this at home kids as it really isn't the best idea). This had absolutely no effect at all.
I stumbled across a forum post about the typical issues of GM's Passlock. The trucks symptoms seem to mimic the Passlock issue, so I hot wired the fuel pump. Absolutely no change: starts and runs for 1 - 2 seconds. In addition, the security light on the dash was steady on the whole time; it didn't blink once. I think based off this info the Passlock isn't the problem.
We put a new distributor cap and rotor on as well due to breaking the old one while shimmying the upper manifold back into place. As it turns out, it NEEDED a new cap and rotor. This didn't change anything either, unfortunately.
My diagnostic tool (Ancel) shows no codes and I tried to read live data with it but that is hopeless due to the engine shutting off.
We don't particularly want to ditch the factory efi as the truck is extremely clean and runs great (when it stays running).
What am I overlooking guys? TIA
He doesn't live terribly close so I couldn't do a normal diagnostic on it easily. We decided to go the hail mary route and ordered a new gm fuel pump assembly and the scpi to mpi conversion. With the mileage on the truck and the fact this is his daily driver, I figured it wouldn't be wasted money, and I assumed the issue would be one of these 2 things. We finally got it back together a couple hours ago and the truck will not stay running longer than 1 - 2 seconds. Here's the things I've tried so far:
Fuel Pressure Gauge on Schrader valve: 60 psi key on, engine off; while cranking the pressure drops into the low 50's
I thought we had a fueling issue and tried to keep the engine running by spraying carb cleaner and pouring gas down the throttle body (don't do this at home kids as it really isn't the best idea). This had absolutely no effect at all.
I stumbled across a forum post about the typical issues of GM's Passlock. The trucks symptoms seem to mimic the Passlock issue, so I hot wired the fuel pump. Absolutely no change: starts and runs for 1 - 2 seconds. In addition, the security light on the dash was steady on the whole time; it didn't blink once. I think based off this info the Passlock isn't the problem.
We put a new distributor cap and rotor on as well due to breaking the old one while shimmying the upper manifold back into place. As it turns out, it NEEDED a new cap and rotor. This didn't change anything either, unfortunately.
My diagnostic tool (Ancel) shows no codes and I tried to read live data with it but that is hopeless due to the engine shutting off.
We don't particularly want to ditch the factory efi as the truck is extremely clean and runs great (when it stays running).
What am I overlooking guys? TIA
