Fuel pump issue
04-04-2016, 07:57 AM
#1
Fuel pump issue I figured I'd ask here because some of you may have experienced this before. I'm having issues with the car breaking up. I've had the same racetonix pump and wiring for 3 years and same amount of nitrous. 2 stages of 100 each.
The car would have a slight hiccup and clear out. Now it's breaking up as soon as I leave the line on nitrous. Even on just a 100 hit. Car runs fine on a motor pass. I put a fuel pressure gauge in the windshield and recorded with the gopro. I get and obvious rapid cavitation from 55 to 30 psi and back on nitrous.
My question is since these cars have the fuel bucket that is filled by the return through the regulator, if the pump is getting weak will in not put out enough volume to supply the rails and fill the bucket. I can only see cavitation happening if the bucket goes dry.
The only other possibility I can think of for the scenario is a fuel pump relay short cycling or the fuel filter is clogged but that is not that old and the socks on the pump assembly were pretty clean.
I tested the assembly in a bucket and have no cracks or broken lines to suck air. Car had between 1/4 and 1/2 tank of fuel.
The car would have a slight hiccup and clear out. Now it's breaking up as soon as I leave the line on nitrous. Even on just a 100 hit. Car runs fine on a motor pass. I put a fuel pressure gauge in the windshield and recorded with the gopro. I get and obvious rapid cavitation from 55 to 30 psi and back on nitrous.
My question is since these cars have the fuel bucket that is filled by the return through the regulator, if the pump is getting weak will in not put out enough volume to supply the rails and fill the bucket. I can only see cavitation happening if the bucket goes dry.
The only other possibility I can think of for the scenario is a fuel pump relay short cycling or the fuel filter is clogged but that is not that old and the socks on the pump assembly were pretty clean.
I tested the assembly in a bucket and have no cracks or broken lines to suck air. Car had between 1/4 and 1/2 tank of fuel.
04-05-2016, 12:03 PM
#4
Do you have a data logger and a wide band to check AFR while its breaking up? Also what plugs are you running? I understand your having a fuel pressure issue, i just want to get and idea of everything. How long is the lean spike lasting? Its always good advice to make sure there isn't any contaminant or trash inside the solenoids. The obvious fuel pressure drop shows a fuel supply issue, but you should rule out the trash to cover all bases. -Matt
04-05-2016, 03:49 PM
#5
Both stages of the plate are flowing fine on both nitrous and fuel. B8efs at .030. No data logger or wideband. I ordered a new pump and housing, fuel filter and will replace the solenoid for the pump. Also am going to put fresh plugs in.
I don't think trash in the solenoid would cause fuel pressure to drop unless it was hung open which is not the case.
I did notice flowing the pump in the car fuel is blowing out around the return after the regulator on the pipe that runs down. It is not blowing out of the regulator itself.
My guess is the pump is just gotten weaker with time. The racetronix pump is 4 years old with daily duty and race duty. I have smaller fuel jets in it this year from leaning out the tune. I have 53/21 in both sides and it won't go down the track on one stage.
I don't think trash in the solenoid would cause fuel pressure to drop unless it was hung open which is not the case.
I did notice flowing the pump in the car fuel is blowing out around the return after the regulator on the pipe that runs down. It is not blowing out of the regulator itself.
My guess is the pump is just gotten weaker with time. The racetronix pump is 4 years old with daily duty and race duty. I have smaller fuel jets in it this year from leaning out the tune. I have 53/21 in both sides and it won't go down the track on one stage.