Fuel pressure question

[imjoesnuffy]

Recently installed a Walbro 340 with the hotwire kit.

Ordered an adjustable FP regulator, hasn't got here yet . I put on a Schrader valve and the extension fuel pressure gauge, so I can see what it is doing at WOT runs. Keep in mind I have stock injectors now.

At idle 36 psi, when the pedal is floored it jumps quickly to 42psi and stays there. Is this enough pressure?

Whenever I get the regulator??? I plan on starting at 42 psi at idle and then tuning accordingly. Dont have a scanning tool but will borrow a friends.

What difference will the additional pressure make? Everyone on every board says I need one to start tuning, will the additional fuel pressure help?

 

[Jerryl]

........ At idle 36 psi, when the pedal is floored it jumps quickly to 42psi and stays there. Is this enough pressure?

Whenever I get the regulator??? I plan on starting at 42 psi at idle and then tuning accordingly. Dont have a scanning tool but will borrow a friends.

What difference will the additional pressure make? Everyone on every board says I need one to start tuning, will the additional fuel pressure help?

FP setting depends largely on your chip.
Sounds like your FP is already at 42 static since the manifold vaccuum gets to zero (no vacuum) when you step on the gas and there is no boost.

Increasing FP alone may not have a positive effect if the chip and supporting mods are not set-up for the increased FP. If the car is running lean at WOT, than FP increase may help. If it is already running rich, ........... well, you know the deal.

If the car is running ok (No KR, no surging, etc), than the current FP is sufficient.

 

[imjoesnuffy]

I should have been more specific.

The 36 psi is with the car running at idle. The 42 psi is actually driving the car at WOT. Didn't disconnect anything for either reading.

 

[Squid4life]

FP should be about 43 PSI with the vacuum line off of the FP reg. Under boost, your FP should raise 1 psi fuel per 1 psi boost. IE: 43 line off, 38ish line on; +10 psi boost= should be 48 psi fuel pressure. If you are not getting more fuel under boost, you could be swapping head gaskets if it detonates.

 

[MoeJr]

If you are at 36 and only going to 42 then u do not have enough FP unless u running only 6psi boost