Lost Fuel Pressure on the way Home
 

Was driving home. Made several hard pulls, everything was fine. Drove the last five miles at moderate speed and the fuel pressure guage starts beeping. The guage is indicating 10 psi. I did finally get it into the garage.

Car has an APS upgraded TT package, with MSD Boost A Pump. I found the 20A fuse closest to the BAP was blown. Replaced, blew again. Upped to a 25A as I have heard people having issue with the 20A fuse. It simply blew the 20A fuse that was feeding the relay block.

I checked the wiring on the relay block, all appears in order. I went back to a 20A fuse in front of the relay block. Fuses are holding. Checked the 20A fuel pump fuse in the main fuse block; it is fine.

I am getting no fuel pressure. Car wont start.

I removed the L (driver's) inner fender liner as advised to check the wiring to the fuel pump. I can see nothing in the area. Only see the filler neck and the ground strap for the filler neck.

Thoughts on what may have happened? Could the fuel pump have died?

I'd diagnose everything with that BAP. I bet it crapped out..

Can you hear the intake pump come on?

It does not make any sound from the fuel tank and the guage stays at 0 psi.

Alan, when you say that the BAP crapped out, does that mean the BAP module died? Time to replace? If I am going to that length, I might as well upgrade the intake pump, lines, rails, larger injectors.... I consider the BAP to be similar to the old FMU as it seems like a "band-aid" approach to solving a recognized problem.

I wonder what a complete new fuel system is going to run? I think some companies make complete kits for the C5/C6 years. Anyone got thoughts on worthwhile fuel system replacement?

Sucks to hear. I had a forum vendor(here in Houston) install a fuel system, and it was a pile of junk. Almost everything has been replaced except a few lines and the rails. Gforce in Pearland yanked it all out, had all hands on deck, and built my fuel system in 1 day while I was there with all 4 techs working on my car. They were about the 3rd shop to tell me it was wrong, so I listened and trust them. Since then, it has worked great. If I wasn't doing that, I would get the ECS stage 2 fuel system. A buddy of mine is having some issues locally with the RSI fuel system and regrets not going with an external pump, boost or RPM referenced on a hobbs switch. But I know another local guy that hated his magnafuel(which I have now) and his Weldon locked up on him like my A-1000 did. Hard to say, but when you go local, you have the backing of the shop.

It is either the pump or the BAP. Bypass the BAP (return to stock) and that will give you your answer.

Over-volting the fuel pump with a BAP will definitely shorten its life.

i bumped up both my fuses to 30A (underhood fuseblock, rear BAP wiring)

Yes if the BAP module took a dump, the fuel pump will not run... Even though the BAP is boost referenced, wiring to the fuel pump runs through the BAP so when the BAP is NOT being boost referenced/increasing fuel pressure, it IS still allowing voltage to go through it to the pump...

If the BAP took a dump, there will be no voltage going through it to the pump.

BAPs work ok but.... I also look at them as bandaids, just like the old FMUs.... Unfortunately I will be running two of those bandaids on my own car...:D

I had heard/read that the MSD BAPs are even more problematic then the KB BAPs.

Should be pretty easy to diagnose if you have a decent DVOM and know how to use it.

Behind the left rear wheel liner, you will find the electrical connector for the fuel pump wiring (it's where I have my Racetronix harness plugged in). See if there is power present when cranking and check the ground circuit. You can also check resistance of the pump itself. If it's an open-circuit, the pump is definitely bad.

I go by the "simpler is better" philosophy with most things. My fuel system is just a factory Z06 pump, and a Kenne Bell BAP with Racetronix harness. Simple, reliable, and effective. If the boost-a- pump goes out on me, I can just unplug the Racetronix harness and return it to the stock wiring setup to get me home.

I considered doing a twin pump in-tank setup -- but after seeing all the problems guys on here have with those types of systems, I decided against it. To each their own, though :thumbs:

Thanks for all of the responses. It looks like I need to take another look behind the L (driver's) rear inner fender liner and see if I can find the connection. I had it apart prior and did not see it.

I better take another look.

And I do like the idea of simpler is better. I really bought the car to be a driver, not a constant project.

Thanks again to all who responded.

The following link shows you a typical driver's side rear fenderwell install of the BAP. I have seen some though installed under the hood near the fuse box.

http://www.aacorvette.com/pdf/aa_bap_install.pdf

Update:
 

I couldn't figure out why I saw no connections behind the L rear fender liner. It turns out that the BAP output is fed all the way down the center tunnel then loops from the underside through the frame by the fuel lines over the top and the fuel pump harness is routed down by the fuel lines and they are connected on the inside of the frame rail.

Everything is held fairly secure, nothing appears to be chaffing, and nothing grounded, nor burnt. I pulled all connections loose, then reconnected and re-wrapped with electrical tape. Tried to start, again no fuel psi and popped fuse on the BAP.

I disconnected everything, inserted two jumpers from the original harness to the fuel pump. Viola, the car fires right up. And the fuse on the BAP did not pop.

So I know the pump is still good. :thumbs: No tank drop, hopefully!

Question:
1) How do I determine if the BAP is still good, or do I simply replace?
2) What are the chances that the BAP output has been shorted along the tunnel or above the turbo? It seems to be in good shape everywhere I can access.
3) Where is the best place to buy the replacement BAP? KB or MSD (currently have MSD)?
4) I really want to replace the relay block for the BAP and the Pimp Pump. Where to source? Does APS still support the C6 partswise?

Thanks for all of the good feedback. These comments have been quite helpful. :thumbs:

At your power level, Get rid of the BAP and get a real fuel system. Don't fear dropping the fuel tank, It's only an hour long project.

AKS I replied to you on MH... Gave you some ideas.

:cheers: