Fuel pressure problem

[84delta]

Sloppy stage 2 turbo cam. It's very mild. Also when I threw the external fuel pressure regulator in the return right after the rail I dialed it into between 58 and 60 psi and still no go. It would idle at that set psi all day and if I took the vacuum off bump up a little but then drop again under load.

 

[84delta]

Ow also I forgot to mention last time I had the tank down I looked over the part # to my pump and it turns out I actually was running a 455lph not 225. I had/have plans of going turbo and e85 so I future proofed my fuel output. I forgot I had decided to go that way.

 

[64nailhead]

That's a medium cam. That will not idle at 44-48 psi of fuel pressure. I have one in my spare 4.8 and in the 5.3 in my car presently. 52-53psi in the 5.3 at 53ish kpa at idle with stock truck fuel rails.

That tells me your FP is low at idle if your FP gauge is reading correctly.

Do you own a Mitivac and an air compressor?


Do you have a log and tune file you can PM to me?

 

[84delta]

That's a medium cam. That will not idle at 44-48 psi of fuel pressure. I have one in my spare 4.8 and in the 5.3 in my car presently. 52-53psi in the 5.3 at 53ish kpa at idle with stock truck fuel rails.

That tells me your FP is low at idle if your FP gauge is reading correctly.

Do you own a Mitivac and an air compressor?


Do you have a log and tune file you can PM to me?

No vac but I do have a compressor. I don't have a copy of the tune handy as the car and my laptop are at my buddies garage but I think this a short data log of the fuel pressure drop.

 

[84delta]

No vac but do have a compressor.

 

[84delta]

That's a medium cam. That will not idle at 44-48 psi of fuel pressure. I have one in my spare 4.8 and in the 5.3 in my car presently. 52-53psi in the 5.3 at 53ish kpa at idle with stock truck fuel rails.

That tells me your FP is low at idle if your FP gauge is reading correctly.

Do you own a Mitivac and an air compressor?


Do you have a log and tune file you can PM to me?

It doesn't seem to be allowing me to attach the data log.

 

[64nailhead]

It doesn't seem to be allowing me to attach the data log.

Send it in a pm. GP403 allowed the website to accept tunes and data logs with the Holley suffixes.

 

[Tony1968]

Just a comparison here. I have a Holley 340lph pump and 6an lines going to a Wix corvette filter regulator combo. At idle i am at exactly 58psi. I had a bad Holley pump brand new with their tank. Sounded like rocks in a can and didn't hit 45 psi dead headed right to a gauge. 340lph that they sent me as a replacement for free deadhead at gauge in a split second pegging needle at 100psi.