BAP/fuel issue? flooding motor?

[Chuckie B]

o drove my 03 cobra to the store etc. Everything was fine... come out. Car tries to turnover and stalls...wont start.
car floods the motor with fuel to the extent of leaking out my exhaust flanges.

I drain oil, pull plugs, let air out for a few days... new oil, new plugs, new frps,... try to start car and same issue...repeat again but this time I disconnect the BAP(boost a pump). and wire back to stock. The car fires and idles fine.

Yet every1 I talk to says the bap cant be the issue etc(kenne bell says they never fail blah blah)...how is it when I delete the bap the car is fine? I dont dare drive it off the bap bc obviously its tuned with it...I moved the car from way bay to the other tho without issue.

The boost a pump is wired after the fpdm
Ive tested voltage from the fpdm and I get 12. So I would believe thats fine bc of voltage and the car running fine when wired back to stock with 30psi fuel pressure at idle

When the BAP is wired in on cycle of key but engine off I get 12.1v on the fuse wire and 15.4v on the red wire out of BAP...this is with it set art 30....at 50 it fluctuates from 16.9-17 does this mean the bap is working? Does any1 know what voltage im supposed to be seeing

Im tempted to just order the BAP and see what happens bc I dont see how it cant be....any other suggestions?

 

[SVTkel]

Well I can't offer much in the way of a solution to your problem. However, I can tell you I had a BAP fail on me. Funny thing is. I was told the same thing that they don't fail. You know anyone else there that can temp loan you their BAP? Then throw their BAP on your car and see how things work. That is how I found out mine was shit.

 

[Chuckie B]

See thats what I was hoping to do...ive yet to find any1 that has one to let me try it...what was your car doing when the bap took a shit?

 

[racebronco2]

I too cannot see how the bap could be causing the car to flood. All it does is up the voltage to the pumps, that's it. Now if you have a fprs' diaphram starting to go bad the higher fuel pressure could cause some leak issues. It's usually a bad fprs.

Yes the higher the percentage on the bap the higher the voltage will be.

 

[Chuckie B]

I already replaced that sensor...that's what I assumed it was from the start.

 

[timspony]

This may sound stupid, but have you checked the BAP fuse?

 

[03' White Snake]

I was having issues with my BAP hooked up after the FPDM.

I was tuned like that. Was fine for 6 months, then the car started cutting out at 4k. My tuner then hooked it up pre FPDM and it has been fine for 2+ years now.

He told me some cars can run it after the fpdm but most cant. The BAP is just adding voltage to the pumps. The cars computer has no idea this is happening and this is why he said its better to run the voltage through the FPDM.

I would try to hook it up pre FPDM and see if that fixes it.

 

[Juiced46]

There really is nothing wrong with running the BAP AFTER the FPDM. Obviously with it before, the computer can control it. With it after you actually have a little more "room" power wise. I have installed many many BAPs over the years and about 90% of them are wired in after the FPDM. I only run them before if their tuner requests it. I have yet to see an issue with it running it after. MJ from Zone 5 who was the originator of the modded FPDMs I talked with him length about running it after the FPDM and he explained to me why it is perfectly OK and preffered that way instead of the before method. I ran it after the FPDM on my Turbo car for many many years and ran it into the 9s and never had a single issue.

That being said. I have been talking to the OP about this issue. I really do not think its the BAP even though it only happens when the BAP is hooked up. But I still need more information. Something funky is going on here.

He said the BAP is getting voltage and when with it is set @ "30" on the out wire of the BAP its seeing roughly 15volts, with it set at "50" its outputting 17 volts. So it is functioning. The thing is the FPDM should be controlling voltage to the BAP. With the key on, it only should output full voltage briefly to prime the engine. It should not be constant. This is a pulse width modulated system. So voltage should drop much lower after the intial Key On. I would need to compare it with another car to verify this though. I think the issue may lie within the FPDM which is causing the BAP to do strange things since the FPDM is supplying the signal to the BAP. I would borrow an FPDM from someone and try that first. Any 99-04 Mustang FPDM will do for testing purposes. It does not need to be a Cobra.

If you want to take a trip to CT. I have a spare FPDM you can have to try.

 

[Chuckie B]

Im just not sure how the fpdm is causing it. If the car runs fine when stock...it reads 12v when key is turned forward and doesnt drop after fuel pressure...how would the fpdm tell the bap when to raise and lower volts?..

One thing i dont understand is why my fuel pressure gauge doesnt read anything when its wired back to stock until the car starts and idles...it then reads 30.. ik before all this happend and the car had the bap installed ik it would read something when the key was turned forward

Are you sure a gt fpdm would work for testing? A friends 03gt is there also and would let me test with it im sure..

 

[Silverboost]

What are your maf counts?? I had an issue a few years ago where my car was commanding 100% duty cycle...turned out my maftextender was malfunctioning causing the ecu to think it was getting a lot more air than it really was...this took me a month to figure out

 

[Silverboost]

My maf counts were off the chart

 

[Juiced46]

The GT FPDM is exactly the same.

I agree with Silverboost as well. my next suggestion is to datalog the car. Datalog it with the BAP out. Log MAF counts, Pump voltage, RPM, Absolute TPS, fuel pump duty cycle, fuel rail pressure, RPM and load.

Fuel pump voltage should not be 12 volts with the car running at idle. The FPDM controls voltage based on demand. At idle you should see very little voltage, once it sees more demand i.e. WOT pulls, the FPDM will boost voltage. This is how a retunless system works. Try the other FPDM if you can. If that doesnt change anything. You need to datalog the car!

 

[Chuckie B]

Have data logged the car some...the front 02s are not even reading...if someone would like to help me out and look over my data logs or give me some info on what to data log and then look at them I would appreciate it...the car is staying in open loop?