fueling issue that's KILLIN MY BRAIN!
07-24-2008, 12:42 PM
#1
fueling issue that's KILLIN MY BRAIN! OK, long story but I'm going to try to summarize it into symptoms and what not.
Car ran for 2 months FINE. No problems with fueling what so ever. Suddenly the pump goes bad. OK, whatever, replaced it. Maybe a week or two later the car has the same symptoms. Car will start up and run fine for the first few miles ~10 minutes, after that period and it gets warm it'll buck hard, anything over 15%+ throttle car just HATES LIFE. Spits, bucks, backfires, doesn't go ANYWHERE. At idle the car will pop like it's lean popping.
At prime the fuel pressure will shoot up to 42psi then on starting the car it drops to 39~40ish psi. Once this whole process starts the fuel pressure drops and bounces at first between 30-40psi. Then drops to 20-35ish psi. Then eventually drops down to 5-10. Inevitably causing me to pull over and what not.
Another strange thing is that when the fuel pressure drops, sometime when I hit the gas, the fuel pressure instead of going up will drop 5-10psi then pop back up to 39/40ish afterwards.
I have checked the fuel pump relay and replaced just to eliminate that. I have tested the fuel pressure regulator, it's working fine. The car however is not fully dyno tuned, but has a pretty good base tune in it.
Last thing is that whenever the car does this, and I let it sit over night, the promblem resets itself. I am completely befuddled. I converted the car from a V6 to a V8, so I'm going over the wiring schematics to see if I missed anything during the process but since it ran fine for over 2 months I don't see that being the problem.
ANY HELP WOULD BE GREATLY APPRECIATED!!!
Car ran for 2 months FINE. No problems with fueling what so ever. Suddenly the pump goes bad. OK, whatever, replaced it. Maybe a week or two later the car has the same symptoms. Car will start up and run fine for the first few miles ~10 minutes, after that period and it gets warm it'll buck hard, anything over 15%+ throttle car just HATES LIFE. Spits, bucks, backfires, doesn't go ANYWHERE. At idle the car will pop like it's lean popping.
At prime the fuel pressure will shoot up to 42psi then on starting the car it drops to 39~40ish psi. Once this whole process starts the fuel pressure drops and bounces at first between 30-40psi. Then drops to 20-35ish psi. Then eventually drops down to 5-10. Inevitably causing me to pull over and what not.
Another strange thing is that when the fuel pressure drops, sometime when I hit the gas, the fuel pressure instead of going up will drop 5-10psi then pop back up to 39/40ish afterwards.
I have checked the fuel pump relay and replaced just to eliminate that. I have tested the fuel pressure regulator, it's working fine. The car however is not fully dyno tuned, but has a pretty good base tune in it.
Last thing is that whenever the car does this, and I let it sit over night, the promblem resets itself. I am completely befuddled. I converted the car from a V6 to a V8, so I'm going over the wiring schematics to see if I missed anything during the process but since it ran fine for over 2 months I don't see that being the problem.
ANY HELP WOULD BE GREATLY APPRECIATED!!!
07-24-2008, 02:46 PM
#2
You will not find an answer to your question here. Most will say that your getting a knock off cheap pump.
Questions.... Is your bucket as it was when it was stock? How low do you let the gas get before you fill up?
Questions.... Is your bucket as it was when it was stock? How low do you let the gas get before you fill up?
07-24-2008, 03:01 PM
#3
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I would defently look over the wires and see if anything was wired wrong or came loose. the pump bucket question ^^^^ is a good one, cause it almost sounds like the pump is falling on its face after fire up, unless you have something in you fuel line, or maybe something clogging the pump screen.
07-24-2008, 05:06 PM
#4
The pump is in the exact same position it is stock. All I did was upgrade to a Walbro 255 pump to help with the change in motor. I've thought about clogging but counted that out due to it running fine for a while then when getting warm it begins to act weird.