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Discussion Starter · #1 ·
If any of you have a BAP wired on all the time, can you do a quick test for me?

Here's how:

1. Key On Engine Off
2. Crank BAP knob from 0% to 50%
3. listen under car(or in trunk) if you hear your fuel pumps running and agitating the fuel

This is very strange. Do you hear it? At what boost percentage do your pumps start running?

Thanks,

MJ
 

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Snake Charmer
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During start up dont the pumps kick on for a second and then off? I wouldnt think just having a BAP in place would make them run since the bap does nothing but amplify the boltage from FPDM to the fuel pumps.
 

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Discussion Starter · #3 ·
Shadowgray03 said:
During start up dont the pumps kick on for a second and then off? I wouldnt think just having a BAP in place would make them run since the bap does nothing but amplify the boltage from FPDM to the fuel pumps.
That's exactly my understanding. However, I wired mine exactly according to the KB directions and that's what happens.

Can you check yours for me? Thanks.

MJ
 

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MJ,

Yes my BAP does this ! I emailed ya too ! I can also watch the Fuel PSI climb slightly with BAP Maxed, Key on,engine off. If I have been running the car and turn off and do this test I can see PSI go from 40 to 65#. Very weird ! But mine is wired as per KB instruction. Think this might be the reason it does not work while running????

Jon L
 

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Discussion Starter · #5 ·
Dustoff said:
MJ,

Yes my BAP does this ! I emailed ya too ! I can also watch the Fuel PSI climb slightly with BAP Maxed, Key on,engine off. If I have been running the car and turn off and do this test I can see PSI go from 40 to 65#. Very weird ! But mine is wired as per KB instruction. Think this might be the reason it does not work while running????

Jon L
Thanks Jon, glad I'm not going crazy! I really don't think that this is a good thing (i.e. the pumps running on with key-on engine-off. I'd like to call KB and ask them about this but the first time I called I got the proverbial run around so I don't feel like wasting any more of my time.

MJ
 

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Well, MJ even without the BAP connected. Stock Cobra don't the pumps run with key on engine off??

I see my Fuel PSI rise when I do it with BAP off. ???

Jon L
 

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Discussion Starter · #7 ·
They come on to charge the line but then they go off. After the initial charging, if you crank the BAP up past a certain point, the pumps start running. Why this happens, I don't know. However, my gut feeling is that the FPDM can not put out zero duty cycle so it puts out some very small duty-cycle that doesn't make the pumps operate. Then when we crank the buss voltage with the BAP, we exceed the voltage at which the pumps begin to spin given the low duty-cycle commanded by the FPDM. Just a guess....

MJ
 

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mjchip said:
They come on to charge the line but then they go off. After the initial charging, if you crank the BAP up past a certain point, the pumps start running. Why this happens, I don't know. However, my gut feeling is that the FPDM can not put out zero duty cycle so it puts out some very small duty-cycle that doesn't make the pumps operate. Then when we crank the buss voltage with the BAP, we exceed the voltage at which the pumps begin to spin given the low duty-cycle commanded by the FPDM. Just a guess....

MJ
Sounds like a good theory, if the BAP is on, although I thought the BAP was on a Hobbs switch activated by boost pressure?

Did you have the pressure switch bypassed? Anyway, it doesn't seem like the pumps idleing around at a low speed without the car running would be an issue. Ford starts them up before every start to system pressure, so I wouldn't think a few RPMS from the BAP would hurt anything.
JT
 
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