fuel presure problems
 

my car starts and idles fine but when you rev it it leans out and the fuel presure goes down ...this is my fuel system i have a wallbro 255 fuel pump ,,paxton fuel prsure regulator with 1 to 1 boost ref vac port,,venom 720cc injectors -8 fuel line all around....for my understanding a boost ref regulator suppost to make the presure go up when vacum is aplied

Re: fuel presure problems
 

boost reference=pressure goes up with boost. got the lines hooked up right to it?

Re: fuel presure problems
 

You do have the vacuum line attached to it correct? Do you have a fpr gauge on it to read the fuel pressure?

Re: fuel presure problems
 

yes i have the vacun line hoocked up and i have a fuel press gauge ...the gauge reads 42 psi at idle and when i rev it it goes down to 30's sometimes 20's

Re: fuel presure problems
 

Even though its a rising rate with boost it will still rise like a normal fpr as negative vacuum goes toward postive. Sounds like its working backwards for some reason. Perhaps you have it hooked up backwards?

Re: fuel presure problems
 

it only has one vacum port and i connected a vacum line coming from the intake manifold

Re: fuel presure problems
 

I was reffering to the fuel side of things. The bottom is likely the fuel return (if its like mine) and the sides are for fuel in and gauge.

Re: fuel presure problems
 

thats how i have the fuel lines connected ....the returns going to the bottom port and the inlet to the side inlet and the gauge to the 1/8 port

Re: fuel presure problems
 

Did you remove the stock fpr? Maybe its just broken? Have you tried adjusting it all to see it that helps....

Re: fuel presure problems
 

Everything is hooked up correctly.

The problem we where having is when the fuel pump comes on (new walbro inline 255) with the engine off it goes up to the 42# that we want, but then after about 4-5 seconds the pressure drops down to 20 or less and then bonces around about 10#.

It does the same thing with the car running(well hardly running) with or without the vacume refrence line connected.
And while running if you tap the gas the pressure will go all the way down to almost 0.

As of now I am betting it is a bad pump. It is slightly lounder than my 255 inline and he did run the tank dry here recently, but it does have a large inline filter before the pump also.

Also everybody...Tell him not to give up on this car. He is so close to having a damn quick little street car. It's a built bottom end (eagle rods, wisecos) He has a nice cam, about the best head you can get, a good size turbo and a EFI that is pretty much ready to go.
I even have an extra inline 255 and regulator that he can barrow!!

Here is the car in question

Car starts and idles with megasquirt and EDIS with 750cc injectors :twisted:
It's just a few small glitches away from being done.
http://www.eville140.com/3tstarlet/l1.jpg
http://www.eville140.com/3tstarlet/l2.jpg
http://www.eville140.com/3tstarlet/l3.jpg


Idle video!!
http://www.eville140.com/3tstarlet/l.wmv

Later
Randy