More fuel pump problems
Thread Starter
Instructor
Joined: Feb 2011
Posts: 241
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From: southeast AZ
More fuel pump problems
I have a 2008 C6 with a Novi 1500 SC, pushing around 7.5~8 psi. Dynoed 501rwhp, 466rqtw. Supercharger was installed around August of last year.
Stock pump lost pressure around 480rwhp (boost-a-pump was not working).
Replaced with Walbro 450, dedicated power line from alternator, and fixed BAP in October of last year, holds *OK* to redline (I say OK because it still drops to roughly 55-56psi, while idle shows ~62).
Over the weekend (Memorial Day), was coming up to speed on an on-ramp and once BAP kicked in, fuel pressure went to 0. All fuses fine, problem is either faulty BAP or fuel pump (haven't had time to diagnose yet).
Any ideas why I'm having issues with fuel pressure? Potentially pinched line? Fuel rails? From what I know, most people just use the stock pump with BAP and it lasts years, with no problems delivering up to 600+ rwhp. My Walbro 450 was 416lph and should have been good way beyond that with the BAP.
Any suggestions on what to replace the pump with? I don't want to go crazy on the pump or have to run lines for a return style setup because it shouldn't be necessary for barely 500rwhp.
advTHXance
Stock pump lost pressure around 480rwhp (boost-a-pump was not working).
Replaced with Walbro 450, dedicated power line from alternator, and fixed BAP in October of last year, holds *OK* to redline (I say OK because it still drops to roughly 55-56psi, while idle shows ~62).
Over the weekend (Memorial Day), was coming up to speed on an on-ramp and once BAP kicked in, fuel pressure went to 0. All fuses fine, problem is either faulty BAP or fuel pump (haven't had time to diagnose yet).
Any ideas why I'm having issues with fuel pressure? Potentially pinched line? Fuel rails? From what I know, most people just use the stock pump with BAP and it lasts years, with no problems delivering up to 600+ rwhp. My Walbro 450 was 416lph and should have been good way beyond that with the BAP.
Any suggestions on what to replace the pump with? I don't want to go crazy on the pump or have to run lines for a return style setup because it shouldn't be necessary for barely 500rwhp.
advTHXance
Thread Starter
Instructor
Joined: Feb 2011
Posts: 241
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From: southeast AZ
. Either way I think you're right, somethings going on I'm not aware of.
Burning Brakes
Joined: Jul 2008
Posts: 923
Likes: 37
From: Green Bay Wisconsin
Hello,
Measuring current draw of the fuel pump is an excellent indicator of the overall health of your fuel system.
The leading cause of fuel pump failure is that the sock at the pickup becomes clogged with debri and as a result you can easily see the current draw of the fuel pump increase. Eventually the pump motor burns out trying to overcome the clogged sock.
Bad connections to the fuel pump will also show an increased current draw.
I suspect that your original problem was debri on your fuel sock and that the Boost pump mearly masked the problem but you saw positive results when the car then ran properly.
You can test fuel pump current draw right at the fusebox with your Fluke Multimenter in place of the pulled fuel pump fuse.
Good Luck,
Douglas in Green Bay
Measuring current draw of the fuel pump is an excellent indicator of the overall health of your fuel system.
The leading cause of fuel pump failure is that the sock at the pickup becomes clogged with debri and as a result you can easily see the current draw of the fuel pump increase. Eventually the pump motor burns out trying to overcome the clogged sock.
Bad connections to the fuel pump will also show an increased current draw.
I suspect that your original problem was debri on your fuel sock and that the Boost pump mearly masked the problem but you saw positive results when the car then ran properly.
You can test fuel pump current draw right at the fusebox with your Fluke Multimenter in place of the pulled fuel pump fuse.
Good Luck,
Douglas in Green Bay
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Thread Starter
Instructor
Joined: Feb 2011
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From: southeast AZ
So I found it. It was a fuse in this power line from the alternator that I overlooked. I remember searching for it, but in the dark and being late, I assumed I was thinking of some other fuse when I couldn't find it. It was a 20 amp fuse. I am not sure if it blew because something caused the pump to surge, or because it has been fatigued over the past 8 months or so.
I am in the process of converting one of my hobby amp meters to plug into the fuse block to see how much power it is pulling, and see if I need to bump it to a 25A since I am running the bigger 450 pump instead of stock.
Thanks for everyones suggestions. I'll try to remember to check back in when I get some data on how many amps the pump is drawing.
I am in the process of converting one of my hobby amp meters to plug into the fuse block to see how much power it is pulling, and see if I need to bump it to a 25A since I am running the bigger 450 pump instead of stock.
Thanks for everyones suggestions. I'll try to remember to check back in when I get some data on how many amps the pump is drawing.
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The 450 doesn't need the BAP. I pulled my BAP when I installed the aeromotive 340 stealth and I'm not having any fuel issues.
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From: southeast AZ
Are you two supercharged? I think I will reinstall the dial to adjust the voltage and see how well it really keeps up. I am not convinced there isn't another issue somewhere, but right now I'm just glad it didn't require dropping the tank and a bunch of money.
Probably take a closer look this weekend.
Probably take a closer look this weekend.
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Are you two supercharged? I think I will reinstall the dial to adjust the voltage and see how well it really keeps up. I am not convinced there isn't another issue somewhere, but right now I'm just glad it didn't require dropping the tank and a bunch of money.
Probably take a closer look this weekend.
Probably take a closer look this weekend.
See my Sig.
Elmer
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Joined: Dec 2005
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From: God's Country, ID
A KB bap and racetronix harness will work well with the oem pump and support 600rwhp easy. It's the oem wiring, connectors etc that is the weak link. Thus avoided via the Racetronix.
Thread Starter
Instructor
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From: southeast AZ
What kind of pressure should be considered too low? I have my alarm set at 55psi.
What kind of power would a stock pump be using with the BAP?
Race Director
Joined: Dec 2005
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From: God's Country, ID
I have the bap set to come on at 3psi via a hobbs switch. The fp is a consistent 60psi. Never does fp fluctuate more than 1-2psi according to my fp guage. The car is making 620whp/620tq w this set-up on the origonal stock 2006 pump.