Smoove

We get lots of already built cars here at my shop, with all kinds of good, and bad stuff on them. Long story short, we have a TT C6 in, that had a bad MSD BAP 2350. 2350 is no longer available, so we could only go to a 2351....which you basically program to your desired specs via laptop.

Since atmospheric is 14.7,...MSD said to use that as my "0" point. So, for example, if I wanted pump voltage to increase at 4 psi, I would start it off at 18.7 and adjust my voltage to match. Since this car only see's 10psi, I need to have my end setting to 30psi roughly. 0psi-10psi (18.7-28.7-or call it 30).

I have done this. My base pressure with a mechanical gauge is 60psi....but when I get into boost, 3-5-7-etc..fuel pressure will drop to 50psi or so on the mechanical. So, after trying various voltage settings, I have no change(no increase in fuel pressure under load). So I decided to go to a lower base start, like 4psi(instead of that 18.7 start point)....now, I go to try that under load-boost, and pressure dropped down to 40psi...

..I believe the vacuum signal for the BAP is coming from somewhere near/around throttle body(the car has soo much chrome engine covers its impossible to see)area. So I am gonna take off some of the chrome cladding and see if I can see the vac line. It does show on my laptop that fuel pump voltage goes up under load, it also shows map sensor changes, so everything is hooked up...just maybe not a good enough signal?????

I dunno but, I am just curious what you guys that have this MSD 2351 are using for your settings. This car is a 10psi MAX car. Am I doing something wrong here or what?

Thanks in advance.

2005-TT C6 auto-stock motor, and I believe stock fuel pump.

Smoove

So nobody here has tuned a new BAP is what I gather?

SBCGENII

Might be easier to get rid of the BAP then to cross your fingers and hope it always works correctly.

I read these directions
http://www.jegs.com/InstallationInst...1/121-2351.pdf
Sounds like you have it hooked up correctly. Have you confirmed the voltage at the pump is changing?

Smoove

Those instructions are really generic, I have a set here that came with the new msd. I have also spoken to msd tech, and we've verified everything is working....it's just not translating into any added fuel pressure. I could be having a fuel pump problem but...thats why I was hoping someone that already has this(msd) can tell me what the on psi and voltage is for theirs that is working properly so I have a KNOWN GOOD starting point.

Voltage does change.

SBCGENII

Well if the voltage at the pump changes correctly I would think the fuel pump is the issue. You could verify with a oscilloscope.

RonSSNova

If you disable the BAP, does the pressure drop worse?
Does the car have a return style system with a boost referenced FPR? (Regulator)

We have tuned a few cars with the MSD box. It seems to be a bandaid at best.....

And you are correct about what you get with customer cars! :-)

Ron

Smoove

It is a stock 2005 fuel system.

I tested fuel gauges with another mechanical so the gauges in car is correct. I have not removed the BAP just yet but we do have another BAP here I would like to check but I would like to know what people are using for their perimeters. Whats your min-max settings?