XLR8 GS-R

I have RC 270's, walboro pump, and the 12:1 fmu. Everything has been running PERFECT since my new setup in late Frbruary. On tuesday of this week- I have noticed my Apex turbo timer has been reading the A/F at 17.2 under about 13 Psi at about 6,500 rpm. Then today when i took my car out, the A/F was reading about 18 under boost at about 7k rpm. Then when i let off- the A/F jumped to 20+. ....So I did another boost run and at about 7k - 8k it feels like my fuel was cut. Loud high pitched noise, then it just hesitated, so i let off. The A/F was reading about 16-17 under that run. I didnt hear any detonation, but there must have been- just couldent hear it over the WG and all. I came home, popped my hood. All lines on FMU are good- but a few weeks ago i did change the bottom line going to the FPR to a slightly bigger one- just cause the other one was cracking... My fuel pump seems to be a little louder than usual too. Whats up!?!

romeo619romeo

basicly your injetors cant take all that pressure... heres a little hint "instead of adding pressure to the injectors get a little bigger injectors and turn down the pressure.. quantity over pressure is always better

b16ahybrid

13psi is a bit much for a fmu set-up.. your just asking for trouble.
What is your complete set-up?

Jared

could be a failing pump, could be failing injectors. That kind of pressure kills everything in the fuel system. Go standalone and start over. That hack setup is killing everyting in the fuel system.

Pelican

what do your plugs look like?
Those A/F numbers seem suspiciously too high

falcongsr

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by XLR8 GS-R &raquo;</TD></TR><TR><TD CLASS="quote">I have RC 270's, walboro pump, and the 12:1 fmu. Everything has been running PERFECT since my new setup in late Frbruary. On tuesday of this week- I have noticed my Apex turbo timer has been reading the A/F at 17.2 under about 13 Psi at about 6,500 rpm. </TD></TR></TABLE>


12:1 FMU yields 13 psi * 12 = 156psi

stock FPR (1:1) yields 13 psi + 50psi (at 0psi) = 63psi

thats 156 + 63 = 219psi

your fuel system was designed to handle 50 psi, and you're trying to push 219psi.

do you see the problem here?

b16ahybrid

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by falconGSR &raquo;</TD></TR><TR><TD CLASS="quote">


12:1 FMU yields 13 psi * 12 = 156psi

stock FPR (1:1) yields 13 psi + 50psi (at 0psi) = 63psi

thats 156 + 63 = 219psi

your fuel system was designed to handle 50 psi, and you're trying to push 219psi.

do you see the problem here?

</TD></TR></TABLE>


Yeah i see a problem.....there is no pump that will support 219psi of fuel pressure, Ok maybe there is but it would require massive reconfiguring. .....

stock will max out at about 80psi and aftermarket will max out about 125psi.....either way 12:1 fmu + 13psi = disaster waiting to happen

XLR8 GS-R

Well its been a few weeks now, and i still ocasionally have the problem. Which is very strange, how it comes and goes.. 3rd & 4th gear i notice the problem worse. My car has been on stands in my garage for the past week or so (doing suspension and break work, and other routine maintnince). The FMU discs are fine- I have been brainstorming why this problem has occured. I thought it was a dirty fuel filter so i replaced with AEM unit. Still having probs. I narrowed it down to the voltage fuel pump is getting. im gonna pull the pump- and run a 10-gauge wire directly from battery. I also got a new battery today just incase. Im also going to put on an external fuel pump (opperated by in dash switch) that i have lying around- hopefully this will work well with the walboro. Ill just turn the external on, when i plan to boost. Cause the last thing i want is to be lean as hell this weekend when im at the E-town SPring Nationals! woooohooooo cant wait! ...I gotta put my baby back together. So what do ya'll think???

XLR8 GS-R

Help? Ideas? Suggestions?

slowsi00

dont run your fmu on 13psi of boost
go standalone

Jared

Think of all that money you're spending, external pump, fmu, etc.. when this could be over if you bought a Hondata, Haltech, etc... The problem could be the pintles in your injectors are just having trouble opening with that much pressure and it only happens occasionally, its also not good for your fuel pump and it could be giving out slowly as well.

falcongsr

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by XLR8 GS-R &raquo;</TD></TR><TR><TD CLASS="quote">So what do ya'll think???</TD></TR></TABLE>

i think you need to set aside some cash for a new motor.

swrdply400mrelay

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by XLR8 GS-R &raquo;</TD></TR><TR><TD CLASS="quote">Help? Ideas? Suggestions? </TD></TR></TABLE>

Like people have said before, ditch the FMU if you want to run 13psi. No fuel pump handles pressures that high.

XLR8 GS-R

Thanks jared, and thanks guys. Well I tried... I ran it like this for at least 4 months no probs. I guess its finally starting to wear down with the fmu setup. I see alot of guys on hear running the F.A.S.T. setup- costly?

kaj

i was told FMU can only handle 11psi??

MikeMAN

is the weather getting warmer???

mike