What is your fuel pressure at startup/idle with the AAM FRS with the Walbro 255. Currently have 440cc injectors. Car at startup is getting hard to start at times...cranking it sputters pretty bad then finally revs on up itself Most of the time it does this after it has been ran some time and is warm. I don't have a fuel pressure gauge in the cabin so I'm just going by the gauge on the regulator. After driving around the block getting it warmed up pulled over let idle for a minute...popped the hood and looked at the gauge...it read at 82-83psi of pressure Is this wrong or what? seems terribly high to me??? Could too much fuel pressure cause injectors not to work properly? With no gauge in the cabin I cant imagine what the pressure goes up to under boost Any ideas??? Also have a strong fuel smell at times...get in smell fuel...start up and its hot as hell so turn on a/c and get more fuel smell for a few seconds then its gone...

Russ

 

Are you sure you are reading the gauge right ? Should be 48 to 52 psi

Did you just finish putting this upgrade in ? and now it running bad ? Or was it running and starting fine and now it isnt ?

 

I'm pretty sure I'm reading it right, the gauge goes from 20psi to 100psi. I even have a very very crappy cell phone pic i took when i started it up from sitting a day, I backed out and then popped the hood. Pressure was at 90psi!!! I can try to get a better pic when I get home today and show it to you. The install was done at cprace just over a month ago. Unfortunately I don't remember what the pressure was when it returned. It was running great and no problems at all. Now im running really lean and pressure way up.

 

here's the crappy pic...kinda hard to snap one with ya cell like that and it be clear haha...but 100psi is to the left...the needle is just at 90psi...

 

check to see if the nut holding the adjustment bolt is loose . If its tight , I would guess something is wrong with the FPR . And take it back to CPracing . They should cover it , if the FPR is bad

 

That's is far too high, assuming that gauge is correct. Baseline fuel pressure should be between 45-60psi, depending on your injectors and other tuning factors.

High fuel pressure can contribute to hard starting, especially when the engine is warm, and needs a leaner mixture to fire cleanly at startup.

 

Hey Sharif....Do you back out the adjustment bolt to increase preasure ? Or tighten it down to increase ? If it has vibrated loose and the adjustment bolt has backed out ....that maybe the cause ???

 

Your turn it clockwise (tighten) to raise the pressure. Loosening (counter clockwise) will reduce the pressure.

 

Well I loosened the bolt to lower pressure. But at idle after four full counter clockwise rotations the pressure did not drop at all. It stayed at about 75psi. Had my fiance' rev the motor for me (oh she enjoyed that) and it would drop to about 70psi??? I'm not sure how far you can actually unscrew that bolt and don't want to go to far and it come out. Is there something that would stop it from coming all the way out? I am suppose to have 440cc injectors. My Utec says its 380cc. Is that because of scaling or what?

 

Thanks..couldnt remember...age you know ...LOL

 

The swirl jet might need to be drilled out 1/64-2/64 if an inch. This will help keep the pressure down.

When you rev the engine, the pressure should rise slightly. If the adjustment screw is too far out, then the pressure will drop. Tighten it just enough, so that the pressure rises when you rev it.

 

I tightened it up and she reved and it still went down instead of up. Also when I rev it up, about 1.5 seconds after it comes back down I hear a whistle (best I can describe it) Its not very loud but you can hear it. Vacuum leak maybe or is this just pressure seeping out the BOV that was built up from reving? Just seems really weird how it was running great for awhile and now its acting weird on me. With running lean and now this

 

It sounds like someone needs to check it out. Your car is running lean, because it appears that the pressure compensation isnt working on your regulator. It could be a few things.

 

guess ill have to give cprace a call...

 

should I try to disconnect the vacuum line and see what it is at first before taking it somewhere? How long does FPR's normally last?