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Desperately Need FP Help

  • Thread starter Thread starter fiveohwblow
  • Start date Start date Mar 26, 2007

fiveohwblow

Official Member
15 Year Member
Jul 21, 2005
2,169
145
155
Mar 26, 2007
#1
  • Mar 26, 2007
  • #1
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

Active Member
Nov 28, 2003
1,044
21
49
Utica, NY
Mar 26, 2007
#2
  • Mar 26, 2007
  • #2
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

"the 5.0 owns all"
Founding Member
Aug 7, 2002
9,516
6
99
Arkansas
Mar 26, 2007
#3
  • Mar 26, 2007
  • #3
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

Official Member
15 Year Member
Jul 21, 2005
2,169
145
155
Mar 26, 2007
#4
  • Mar 26, 2007
  • #4
5spd GT said:
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.
Click to expand...

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

"How long does it take to get help in here?
15 Year Member
Nov 29, 1999
31,179
33
129
Mar 26, 2007
#5
  • Mar 26, 2007
  • #5
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

Official Member
15 Year Member
Jul 21, 2005
2,169
145
155
Mar 26, 2007
#6
  • Mar 26, 2007
  • #6
HISSIN50 said:
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.
Click to expand...

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

Active Member
Nov 28, 2003
1,044
21
49
Utica, NY
Mar 26, 2007
#7
  • Mar 26, 2007
  • #7
Good luck to you brother, let us know how you make out!
 

fiveohwblow

Official Member
15 Year Member
Jul 21, 2005
2,169
145
155
Mar 28, 2007
#8
  • Mar 28, 2007
  • #8
Flavadave4 said:
Good luck to you brother, let us know how you make out!
Click to expand...

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

My Grandpa has great wood.
Sep 13, 2004
2,487
4
0
Miami, Ok
Mar 28, 2007
#9
  • Mar 28, 2007
  • #9
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.
 
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