Fuel Pressure Questions...

[NothinButNotch]

1) Where do you have your FP set (and specify vac on/off)?

2) How high does your FP climb when you are at WOT?

3) If I had mine set at 44 (vac on) and then bumped it to 58 and I'm still experiencing detonation then its not a fuel delivery problem is it?

4) When I had it set at 44 psi it would climb to somewhere b/t 55-60 psi when I got on the gas. Does that sound about right?

Thanks for any info, Ryan

[slow91]

Mine is set at 42 with vac off. i don't know where it goes at wot. I have a similar setup though, same heads, pulley, inj...etc some timing was pulled out with superchip, initial is at 10deg.

[NothinButNotch]

Ok thanks slow91. Something is definately wrong with mine I just cant figure it out to save my life. I pulled the chip this evening and took the base timing down to around 6* and bumped the FP up to around 50 psi and it still pinged at part throttle and WOT. I'm beginning to think more and more it is related to some sort of issue with my lower intake (bad seal on head/intake gasket or RTV didnt seal up all the way, etc). Thanks for the info though, Ryan

[PNY PWR]

mine's set at 39psi w/ the vac off. only have the gauge under the hood so i don't know what it goes to under accel.

still have my base timing at 6-7* w/ no pinging. tried locking out the timing at 22* and it didn't run very well.

Could i run more timing if i raised the fuel pressure? It may just be my old carboned up motor that won't let me run much timing.

[BlownNotch]

Is it possible you are seeing high pressure but not enough volume? Sounds like a simple problem somewhere, a kink or debris somewhere. Have you used a different gauge? After removing the fuel pressure gauge from my hood and putting a small one on the rail I realized I've been trying to get a good tune with a gauge that has been reading 12 psi high for who knows how long! Just a thought.