What is "normal" fuel pressure?

[svteet93]

I have a 93 cobra that I bought with a list of mods and noticed it has a fuel pressure gauge on the line under the hood...seems to be running about 36-38...is that good? (It has 24# injectors...190 fuel pump....gt40X ford motorsrorts create motor....)...runs extremly rich ....I cant even leave it in the garage running for 5 seconds before It gags me out with raw fuel smell...

 

[TheUser]

If the vacuum line is attached to the fuel pressure regulator, you're probably running a bit rich (as you found out). You set the fuel pressure with the vacuum line disconnected from the fuel pressure regulator. Try this:

Disconnect the vacuum line from the fuel pressure regulator...the pressure will shoot up. Back it down to ~38-39psi. Stock is ~38 and you probably won't need much more than that. You can always adjust if you feel that's not enough. Be sure to reconnect the vacuum line and the pressure gauge will go down to probably 32-33psi because the vacuum is sucking on the line. Drive it and see if that works. If you need more, follow the same procedure and bump it up a pound and try again.

Good Luck

 

[vristang]

Pull the codes...

 

[TheUser]

vri: wouldn't you say the fuel pressure is a bit excessive? 36-38psi idling with the vac connected?

Sure, pull the codes, but I'd definitely back that pressure down and adjust accordingly.

 

[HISSIN50]

It stinks while idling. A lack of emissions equipment can cause that. And at idle, the puter should be pulling PW to accomodate the slight bump in the FP. A WB is one of the few ways to know what's really going on. Otherwise, we all just guess.

It would be helpful to know what the simulated WOT FP is (see James's post for how to check). Some AFPR's don't have much of a pressure delta with 20" hg vs zero vac applied.

Otherwise, if there's an issue, it very well might lie elsewhere.

Good luck.