I have a 14b, FMU, stock injectors, dsm fuel pump,and running 8lbs(stock wastegate actuator diaphram is set at)

When i hit full boost it goes soo lean that it actually breaks up.

2 questions is it really even safe to run 12:1 fmu? Thats friggin 96psi fuel pressure, on top of 35 psi basline...DAMN!

Also does the b&m fuel pressure gauge peak and hold? If i shut my car off its still setting at 35psi im guessing its just measuring the pressure in the system.

I dont see how i could see fuel pressure under boost since i would have to be driving....this sux

 

do you have a gauge,im guessing you do,just pull off your vacuum line,blow in it with the car running,the pressure should rise as you blow,this is how i tested mine and my boost retard.

 

Buy an in-car fuel pressure gauge. Expensive, but waaaay cheaper than rebuilding your motor! I seriously doubt that DSM pump is keeping up with your fuel demands. You're asking for 120+ psi. The pump falls on its face long before that.



You need bigger injectors and/or an inline pump.

Sonny


[Modified by Sonny, 7:16 AM 11/5/2002]

 

a walbro cost 99 dollars 2nd day air, chekc out the best buys.

 

walboro's aren't that expensive...

http://www.autoperformanceengineering.com

75 bucks with a cash discount...

 

Or I'll sell you my used Airtex in-line fuel pump (came with the Drag Gen III kit) for $50 shipped. Worked great for me without any problems.

 

Whats the LPH?

Thanks
Chris

Thanks for the help btw guys!!!


[Modified by BorderM3, 6:07 PM 11/5/2002]

 

good question... hopefully someone knows. I'm sure it is more than capable as it is included in the kit, intended to be used with the fmu. When I used it with the 12.1 fmu on my gsr kit I was running in the range of 12.5 a/f ratio on a very cool ~50 degree day. The pump is capable of 120psi of pressure.

 

i am having the same problem. i am only running 5-6 psi though. i got the autometer in car fuel pressure guage and at wot, full boost i an only getting about 50 psi. although i do have an in line pump, so i think it is my fmu.