Post FPDM Boost A Pump Install

[EvilTwins]

Just so you guys know I rewired it to pre-FPDM and it does seem to be working great! At least it definitely turns off now anyway haha and the car seems to idle a little bit better.

Here's a pic of my install:

You'll notice I never used the wiring upgrade relay connector plug because I think it's stupid. Why bother even running 8awg to the relay if it gets reduced to like 12awg or whatever a foot before the relay. I also think it looks cleaner without the connector but maybe that's just me

 

[jm@ReischePerf]

You'll notice I never used the wiring upgrade relay connector plug because I think it's stupid.

:beer: Glad you got it worked out. I didn't use a relay plug either :thumbsup:

 

[Justin@VMP]

I haven't read the whole thread, but I've got some wiring diagrams here:

http://vmptuning.com/downloads/wiring_diagrams/Mustang/

Keep in mind the 03/04 cobra is wired slightly differently than v6/gt/mach1/NA cobra. But otherwise all 99-04 are the same.

Technically the computer does need to be tuned for the fuel pump setup, so the voltage table can be correct, but it will still run okay without doing this until you can get it tuned, and the computer will ultimately have more control with the BAP installed pre-FPDM, which is a good thing.

 

[laruei]

....I would recomend to change the BAP to pre FPDM, since you have change it anyway. If you do, hears how:

Relay pin #87-is OK
Relay pin #30-goes to the Red Fused BAP input wire
Relay pin #86-goes to the DG/YE Wire from the stock wiring harness
Relay pin #85-is OK

The BAP Red output Wire goes to the DG/YE Wire to the FPDM Conector Plug
Reconnect the BR/PK Wires together.

Ok guys...

I wired mine EXACTLY like this ^

First I had read the how to guide from the lethal here.
Google Docs

It was a far more confusing way of saying what you just did. At any rate it didnt work so i was scratching my head. So now the Gr/Yw is still cut.

I then found a guide on wiring it AFTER the FPDM with the brown(grey)with a pink stripe. And then that didnt work. So thats still cut.

I have checked that the 8 awg power wire is hot from the battery and going to the correct pin (87). I have replaced the relay thinking possibly it was bad. I have checked the fuel pump fuse (30 amp) at spot 14 in the fuse box. I have also checked the fuse (30 amp) on the red fused wire out of the BAP. I have checked the grounds.

I bought this BAP used. Is there anyway to test it? I reverted all the wiring back to stock and it worked first try.

I (of course) am trying to get this up and running by friday. So i can get the car tuned on Saturday.

Any and all comments please bring em on. Thanks once again SVTP :rockon:

 

[cobracide]

Get rid of all that extra wiring, it adds resistance to the circuit for no reason.

 

[snakerider]

sub

 

[laruei]

Ok, update. Through one of my "configurations" that i tried i must have blown the fuse on the BAP red fused wire. Cause i replaced that and used the relay that the kit came with and after that it worked perfectly.

So note to everyone. CHECK EVERYTING MULTIPLE TIMES.

Thanks for all the help

 

[Heater]

Just wanted to say that when I searched for installing my BAP, this thread came up and was a huge help with my installation :beer:

 

[snakerider]

Yeah I want to thanks you guys too for starting this thread. It came in handy when I installed my BAP couple of weeks ago.:beer:

 

[BigBeez03]

I'm in the same boat now as "Evil Twins" was a couple of years ago. I had my BAP installed post FPDM and now the BAP is staying on all the time and killed my battery. I am pissed about this as I'm not a mechanic and am lost when it comes to wiring up the BAP. Is there a simple fix, without wiring pre-FPDM? I know this has been discussed already but put my mind at ease and tell me will I have to retune if I move the BAP to pre-FPDM position?

 

[cobra=trouble]

heres what you looking for i think scoll down

http://www.svtperformance.com/forums/engine-tuning-214/700032-k-b-bap.html

 

[bubblehead93]

good old thread, for the record...

I would def install the BAP PRE-fpdm. If you install it post fpdm the pcm no longer has full control over the pumps and can cause some tuning issues. There is no disadvantage of installing pre-fpdm. You won't fry the bap this way. I have mine wired pre-fpdm and running full time as I don't use the boost switch that comes with the kit. I set mine to 40% and it's been there for the past 54k miles with no issues. OH and there is not any tuning required if you move the bap to a pre-fpdm configuration.

not quite correct. i've datalogged both and you can watch fuel pump duty cycle (fpdc) and actual fuel pump voltage (afpv) respond as expected in both cases, ramping up during 1000 rpm to 6500 rpm wot pulls. the real issue for the bap post-fpdm has to do with fpdc and afpv fluctuations.

why the fluctuations. the kb bap is designed to work post-fpdm with a hobbs switch. as a result it has a triggering ckt. as the stuttered voltage comes out of the fpdm, if the peak is less than the reference voltage (0-50%) the kb bap triggers and boosts the voltage accordingly. the reason why i think kb used a hobbs switch is because the bap triggering ckt "misfires" at low fpdc's. thats my theory. one of these days i'll test it with an o-scope. what i do know based on data logs is that at high fpdc's (wot pulls for example) you cannot distinguish between the logs for the bap installed pre or post fpdm. however when cruising, coasting, or idling you see all sort of fluctuations with the bap installed post-fpdm. it is useful to think of the fpdm output not as a constant dc voltage, but as a square wave aleternating between 0 volts and peak voltage (12.5-13.0 volts or higher if runninf the bap pre-fpdm). the result is an average voltage (rms to be more precise) that the fuel pumps effectively see.

if you search google you can find some great o-scope screen captures of all the deifferent signals associated with the fpdm.

bottomline: install the bap pre-fpdm. to make the fuel pump voltage tables precisely match reality you could need a re-tune. the issue is any voltage loss from the bap through the fpdm. it should not be much. i would just datalog a few wot pulls on the street (2nd gear for example) and compare actual fuel pump voltage with the associated voltage table value. if they are very close then you may not need a retune but you'll probably need to.

good luck.

:beer: