Desperately Need FP Help

[fiveohwblow]

Well, I was scheduled to go to the dyno at 9AM Pacific time and was thwarted after I let my car idle to warm up. Here’s what happened...

I just did a H/C/I swap to an Ed Curtis custom cam, a set of Trick Flow Tw's and a Ported Cobra intake. I also have a Vortech SC and used to run the 30's with the infamous FMU band aid. I ousted the 30's in favor for a set of 42#'ers. My fuel pressure used to be set at 42 lbs and I think that is far too much with the new injectors. It idles beautifully as though I did nothing to it, however if I kill it nonono: I know, I suck) then I can’t get it started again without letting the fuel clear out of the cylinder(s).

My question to you tech sections is; what should my fuel pressure be set at, and do you do it at an idle, or with the key in the ignition in the on position? Thank you very much for your responses.

Keep in mind, I have an accufab FPR, 255 lph walbro pump, and flow matched 42 lb injectors.

Thanks guys!
:SNSign:

 

[Flavadave4]

Fuel pressure should be set on a warm engine, at idle with the vac line off.......I would think yours should be set in the 40psi range, not sure though?

 

[5spd GT]

Nice car by the way...

You set the fuel pressure at idle with the vacuum line disconnected. You may have to play with it, and a dyno tune would be best so schedule one when your time allows.

Try 35psi with vac. line disconnected, and then 38, etc. A dyno would be great though.

 

[fiveohwblow]

Nice car by the way...

You set the fuel pressure at idle with the vacuum line disconnected. You may have to play with it, and a dyno tune would be best so schedule one when your time allows.

Try 35psi with vac. line disconnected, and then 38, etc. A dyno would be great though.

Thats where I was on the way to unfort... I had to call my tuner and cancel... thank you guys for your immediate responses! Any other info would be greatly appreciated.

Thanks for the compliment!

 

[HISSIN50]

I agree with David and others - it sounds like a cranking fuel issue because of the lack of tune. Most tuners want the FP set to stock or near stock specs (they let the tune modify from there - we change FP as a band-aid of sorts if we cannot self-tune).
You might just have to limp or tow the car to get tuned.
Of course, I'd also run this by your tuner to see if he agrees or wants you to do anything special.

Good luck.

 

[fiveohwblow]

I agree with David and others - it sounds like a cranking fuel issue because of the lack of tune. Most tuners want the FP set to stock or near stock specs (they let the tune modify from there - we change FP as a band-aid of sorts if we cannot self-tune).
You might just have to limp or tow the car to get tuned.
Of course, I'd also run this by your tuner to see if he agrees or wants you to do anything special.

Good luck.

I appreciate it! I just got off the phone with him and that is exactly what he wants me to do.. I have to turn the pressure down enough to make it to the place of tune, then we can commence... I appreciate all of your replies, and your good help!

 

[Flavadave4]

Good luck to you brother, let us know how you make out!

 

[fiveohwblow]

Good luck to you brother, let us know how you make out!

Well, I did alright, thats for sure... not quite where I wanted to be, but it sure runs like a raped ape! Cant wait to add more!!!

 

[Foxfan88]

dont forget to cap the vac line with your finger when u adjust FP.

as for what it should be, just tinker with it on the dyno. every engine is different, just got too see what it likes.