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Kenne Bell Boost-A-Pump issues?

Discussion in 'Engine/Tuning' started by POPO30, Apr 14, 2011.

  1. POPO30

    POPO30 New Member Established Member

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    I have Kenne Belle Boost-A-Pump wired up after my stage 2 fuel pump driver. Im running the Ford GT pumps. I also have the Wiring upgrade for the boost a pump. All my connections are soldered and secure. When I go to start the car QUICKLY I keep blowing the boost a pumps inline 30amp mini fuse. If I turn my key to the ACC position and listen for the Boost-A-Pump to turn on, then start the car, the fuse does not blow? Any suggestions?
     
  2. pdm

    pdm Newbie Established Member

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    First, It should not be coming on until you're under load and need the fuel. Second, all the wiring upgrades are to support the higher current draw from the bigger pumps. The pumps appear to be drawing more than 30A when they first start up. Someone else will have to chime in on the need for a higher capacity fuse on the GT pumps. If that is not the case, I would bet on a high resistance connection somewhere.
     
  3. POPO30

    POPO30 New Member Established Member

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    My car has been on the dyno. I have the 2.9l Whipple and supporting mods. I did the entire install myself, along with the new blower and supporting mods on my GT500, so dont talk to me like Ive never wrenched on a mustang, (SORRY IF IM TAKING YOUR MESSAGE THE WRONG WAY). As far as how I have the boost a pump wired, to be on at all times......Kenne Bell suggested it as did the instructions with the wiring upgrade. While on the dyno the voltage dropped at the top of the rpm range with the GT pumps. Thats why I have the boost a pump. I also upgraded the 20A fuse in the fuse box to a 30A. I just went out and replaced the relay and re-did the grounds. All is good except, I noticed that when I start the car then shut it back off, the boost a pump still has a very very slight hum to it until I unplug the relay. But when I plug the relay back in, it does not continue to hum until I start and shut the car off again. Obviously the hum from the boost a pump is MUCH louder when the car is on and running.
    Also, I know the boost a pump is working properly under load, because I data logged the duty cycle of the fuel pumps earlier in 4th gear at 6500rpms. They ran at .30, which is about 70-75% duty cycle. Thanks
     
  4. Jimmysidecarr

    Jimmysidecarr Semi user friendly Staff Member Super Moderator

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    Most BAPs are wired full time that I have seen, as the OP is running his.
    Mine is too, with the Hobbs switch wires just connected together.

    However mine is wired PRE FPDM not POST, and mine is using a 40 amp fuse even though I am only on stock pumps.

    I wish I had an answer for you OP, but I don't.

    I have heard of people just putting in a 40 fuse instead of a 30, but I do not know if the situation was the same as with yours.
    I am just not familiar enough with the post FPDM installation.
     
  5. POPO30

    POPO30 New Member Established Member

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    Ok thanks Jimmy, I tried to find the 40amp mini fuses but havnt been able to yet? The only other issue then is why isn't the relay switching off completely? Where is the voltage feed back coming from?
     
  6. Brutal Metal

    Brutal Metal Active Member Established Member

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    wire it PRE-FPDM
     
  7. POPO30

    POPO30 New Member Established Member

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    Why? Tell me what you know! I have read that pre fpdm will send a signal to the PCM and it will lower the voltage to compensate for the voltage spike? Says if your over 550hp wire it after fpdm? I'm at 680hp. If you know something please tell me.
     
  8. pdm

    pdm Newbie Established Member

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    Popo, I was not trying to insinuate your level of knowledge. I apologize that it came across that way. My reply was nothing more than my best attempt to help find the cause of your problem. I always start with the basics when troubleshooting.

    A non-constant BAP setup is more just my preference than necessity, and it certainly shouldn't cause this issue unless something else is wrong.

    A pre-FPDM setup doesn't make sense to me either. Please explain how this is better? A BAP is just a step-up transformer. Why would it need to be applied to anything other than the pumps?

    What BAP are you using? Do I understand correctly that the OE fuse was a 20A? If you are running a 20A BAP, that is certainly your problem. I am assuming that you are running the correct 40A BAP, but that should not have come with a 20A fuse.

    Edit: Sounds like the hum is just a bad relay. Where is the switched power coming from? Check the voltage on that source?
     
  9. POPO30

    POPO30 New Member Established Member

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    Ok no big deal. The factory fuse under the hood for the fuel pumps has been swapped with a 30a instead of 20a fuse, this one is fine. The fuse that I keep having trouble with is the one that came with the boost a pump. It is in it's own holder and is wired to the relay. So it goes from the boost a pump to the relay. I have installed a new relay already. The hum sound I'm hearing is def coming from the boost a pump. It sounds like the boost a pump is turned all the way down or lower. When I unplug the relay the sound stops. If I plug the relay back in it does not continue. Until I turn the car on and back off again. The the hum is there until I again unplug the relay. Is it possibble I have gotten two bad relays in a row?
     
    Last edited: Apr 15, 2011
  10. POPO30

    POPO30 New Member Established Member

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    I am using the 40a boost a pump.
     
  11. pdm

    pdm Newbie Established Member

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    Ok, let me know if any of this is incorrect. You have a factory fuel pump circuit that acts as the switch for the relay. If you have not upgraded every wire on that circuit, it should remain a 20A. Why did you switch it to 30A? Did you have a problem with blowing the 20A fuse since installing the BAP? The other two legs on the relay run to battery and BAP.

    What capacity fuse is currently on the BAP? if it's not 40A, it will blow. The BAP will supply the 40A, and I guarantee those twin GT pumps will draw close to 40A. I am lost as to why KB would supply anything other than a 40A fuse. If that is a 40A fuse, your problem could be anywhere between the fuse and the fuel tank (BAP, pumps, or associated wiring). How is the FPDM wired in?

    I believe the hum is an unrelated issue. If you turn the ignition off, and the BAP continues to hum, it is obviously getting voltage from somewhere. This can be one of two things. Either the relay is sticking, or the fuel pump circuit is still sending a signal to the relay. I doubt the latter, because a properly functioning relay would be on or off, and I understand you to say that the BAP is definitely getting less than 12v. If you're buying quality relays, it is unlikely that you have two bad ones in a row, but if they're Taiwan junk off of eBay, that is very possible. Here's a quick check you can do to determine which is causing the problem. Turn the ignition off, and if the BAP continues to hum, pull the fuel pump circuit fuse under the hood. If the hum does not quit, you have a bad relay. If it does quit, something is not switching properly. We can figure this out, when I know how your FPDM is wired in. GL!
     
  12. redfr03svtsnake

    redfr03svtsnake Import Killer since 03' Established Member

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    Ive never heard my BAP hum...... thats strange.... do they all hum?
    I think there is definitely an issue with the way its wired. NO OFFENSE but i had mine with one wire done wrong when i wired the dual fpdms and bap, and it was blowing fuses. I dont remember how i did it, but i am acutally going to go over everything i did tomorrow night, and make sure that mine is post FPDM..... a guy on here black306 or blackz06 or something was the man that helped me, and he knows his stuff !
     
  13. POPO30

    POPO30 New Member Established Member

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    Ok, so today I wired the boost a pump pre fpdm and it works absolutely normal. I changed NOTHING but switched to pre fpdm? For those who know the wiring on these cars, I changed it from the brown with a pink stripe wire to the green with a yellow stripe wire. I have no idea why I was getting voltage feed back when it was wired post fpdm?? Everything works perfect now?? I don't understand it at all. I data logged the car in 4th gear at 6k(had to get out of it due to speed), and duty cycle went to .38-.41. Which with two pumps is at about 75-80%.

    Before doing this I swapped out fpdm for another and even double checked to make sure that the brown and pink wire was indeed the one that went to the fuel pumps. I had it wired correctly for post fpdm.... I'm assuming that now when the fpdm is signaled to send more voltage to the pumps by the PCM, it will have it from the boost a pump. I'm still questioning how amplifying and amplifier will work with out an issue but it does. Any thoughts?
     
  14. Black306

    Black306 Active Member Established Member

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    A little late to the game, but I'd like to play. :rockon:

    A BAP was originally designed for a return style fuel system where the fuel pump receives full voltage all the time. The idea was to use a Hobbs switch to kick up the voltage only under heavy load.

    When Ford's returnless fuel system came about, and not knowing any better, people at KB probably thought it was best to locate the BAP as close to the fuel pumps as possible. That way, any voltage being sent to the fuel pumps would simply be amplified by the BAP. Part of the problem with the instructions is that it still includes the use of a Hobbs switch. That 'spiked' increase of voltage to the pumps when the Hobbs switch is activated wreaks havoc on a returnless fuel system cause fuel pump control is critical to maintaining fuel pressure. Another reason people at KB probably thought it was best to run a BAP after the FPDM is because they didn't know whether or not an FPDM could be run at up to 17v reliably. Now we know that an FPDM can reliably run with increased voltage* (but it is recommended to run a modified FPDM just in case....but those details should be left for another thread :lol:). Time has shown that running a BAP pre-FPDM is indeed better.

    Why is running a BAP pre-FPDM better? Well, an FPDM is really nothing more than a fuel pump speed controller or voltage controller. Depending on input from the ECU, the FPDM will supply more or less voltage. It's really that simple. When you run a BAP after the FPDM, the ECU has no direct control of the voltage getting to the pumps; a BAP can change what the pumps actually receive. When you run a BAP pre-FPDM, all you are really doing is supplying the FPDM with the voltage it needs. The FPDM will still manage the power to the pumps as the ECU sees fit.

    If you followed the KB BAP instructions to a "T," then power is being supplied via the stock wiring. That is why the fuse is upgraded from a 20A to a 30A in the stock fuse box; power demand increased due to the BAP. However, if you added a relay and did a "wiring upgrade," then there is no point to installing a 30A fuse in the stock fuse box cause that circuit is simply a low-current signal now to activate the relay. Power would be supplied through a new wire from the battery.

    Now, why were you blowing fuses with your BAP wired post-FPDM? No clue. If that has happened to other people, it hasn't happened to many. In your particular situation, obviously there is something causing a significant spike to pop the fuse when you go to turn the key all the way. Assuming everything is wired correctly, it could be that the cranking fuel table is demanding a bit more fuel in your tune and enough to cause the excessive spike. Much like going from off to full on, but I'm reaching on that one.

    In any event, the problem is moot. It is good that you switched to a pre-FPDM setup and that you are no longer having the problem. :beer:


    Actually, a "40A BAP" is shipped with a 30A fuse. Go figure. Also, a pair of GT pumps pull closer to a maximum of 23A. Even a pair of Aeromotive 340 pumps, which significantly outflow GT pumps, pull about 26A.

    You are correct in thinking .38-.41 is about 75-80% duty cycle. Really, that PID has a range of 0-.5 where .5 is 100% regardless of the number of pumps. So your PID showing .38-.41 is really 76-82%. Considering your horsepower, that's about what I would expect.

    Thanks. I don't have a Z06 yet. I've considered it from time to time. :burnout:
     
  15. Brutal Metal

    Brutal Metal Active Member Established Member

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    YEAH what Derek said^^^^^
    PRE-FPDM and the issue is resolved..
     
    Last edited: Apr 16, 2011
  16. Schlangenbisse

    Schlangenbisse Need Terminator friends!! Established Member

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    Can you guys tell me what the voltage should read when you use a volt meter on the BAP?
     
  17. Black306

    Black306 Active Member Established Member

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    It depends on the setting of the BAP. Maximum is about 17.5v.
     
  18. lxtasy93

    lxtasy93 The Wheelman Established Member

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    Subbing for reference!
     
  19. horspla2000

    horspla2000 New Member Established Member

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    Old one, but I just installed GT pumps and I'm blowing the 30A fuse at the BAP and running VERY rich. No, the FRP diaphragm didn't blow. I'm going to install a 40A fuse, have seen this in a few places while digging. I haven't had much time to mess w it yet, but thinking some other issue is there.
     
  20. mrose75

    mrose75 Active Member Established Member

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    I'm a complete idiot when it comes to anything electric. How does Pre vs Post FPDM affect draw on battery/alternator, or does it at all. Having voltage issues that coincide with buzzing at my BAP.
     

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