Help with fuel pressure problem!!
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Joined: Nov 2005
Posts: 57
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From: Memphis Tn
Help with fuel pressure problem!!
I have been working on a 2006 corvette conv. with the sts twin kit. I just installed a new pair of gtk 650 turbos and a kb boost a pump. Anyway, I had it on the dyno making some pulls. It made 655rwhp and 570 rwtq. A/f was in the mid to low 11's and the egt's were high 1300's so it was safe. I wanted to let the car cool off and make some final pulls just to make sure that it was going to be as safe as it can. Well when i came back from lunch I started making a couple of pulls didn't change anything and the fuel pressure starts dropping from 60psi to close to 40psi before I shut it off. I have no idea what changed between when i went to lunch and when I came back but I am baffled. I checked the fuse on the boost a pump and that was good. I guess maybe the next thing is I need to see if the boost a pump is still coming on. Anyone else have any ideas?
Pro
Joined: May 2000
Posts: 610
Likes: 1
From: Midland Texas
St. Jude Donor '09-'11
Did someone turn the **** on the BAP back to zero while you were at lunch? Is it on a boost switch? Check the switch.
How much boost? Are you reading the fuel rail pressure or the fuel injector differential pressure?
How much fuel pressure did you have on the run before lunch when everything worked OK? 58 psi constant?
If the BAP fuse blows, the pump won't run at all.
That's a lot of power for a stock pump even with a BAP, by the way. Any chance the fuel pump was changed out before and maybe is leaking in the tank now? Maybe a hose failing?
Just trying to throw out some ideas. I've seen hose clamps that were not tight enough start leaking when the BAP came on on a test stand that didn't leak earlier.
How much boost? Are you reading the fuel rail pressure or the fuel injector differential pressure?
How much fuel pressure did you have on the run before lunch when everything worked OK? 58 psi constant?
If the BAP fuse blows, the pump won't run at all.
That's a lot of power for a stock pump even with a BAP, by the way. Any chance the fuel pump was changed out before and maybe is leaking in the tank now? Maybe a hose failing?
Just trying to throw out some ideas. I've seen hose clamps that were not tight enough start leaking when the BAP came on on a test stand that didn't leak earlier.
Last edited by Joe Lynch; Jun 22, 2008 at 07:36 AM.
Racer
Joined: Aug 2007
Posts: 397
Likes: 0
From: East Longmeadow MA
temperature
in the morning the fuel was colder. after lunch fuel is hotter. This can make a huge difference.
Hot fuel is harder to pump since it makes gas bubbles in the turbine pump and performance falls off like you described.
What do you know about your fuel? Winter grade (worst here) or summer? Any additives throwing a curve too?
Hot fuel is harder to pump since it makes gas bubbles in the turbine pump and performance falls off like you described.
What do you know about your fuel? Winter grade (worst here) or summer? Any additives throwing a curve too?
Le Mans Master
Joined: Aug 2002
Posts: 8,472
Likes: 38
From: Houston TX
St. Jude Donor '11
Also, if it's an Autometer electric FPG those senders have been known to start reporting low pressure when they get hot. Did the AFR go lean as well or did it look the same as the morning run?
