What should my fuel pressure be?

[Torch Red 10th]

Just installed Autometer fuel pressure gauge.

1) What should it read at idle?
2) What should it read during WOT?
3) What is considered too low and a problem?

Thanks,
Torch

 

[Sonic03inSC]

Originally posted by Torch Red 10th
Just installed Autometer fuel pressure gauge.

1) What should it read at idle?
2) What should it read during WOT?
3) What is considered too low and a problem?

Thanks,
Torch

1. Mine reads 29-30psi
2. 50-55psi
3. ????????

Mine also will dip below 20 after lifting @ WOT. If I get on it and then lift and leave it in gear to cost the pressure will rise to 60 psi slowly untill I touch the gas.:shrug:

 

[Torch Red 10th]

Well......just went for a drive.

30 psi at idle
40 psi while cruising
60-63 at WOT

At idle it dips to 25 psi if I rev above 40 psi and let off, then recovers to 45 psi and then drops back to the 30 psi idle.

Seems to sit anywhere from 35-50 psi after the car is shut off.

I guess it's okay. Not very consistent.

 

[02yellowgt]

Mine also will dip below 20 after lifting @ WOT. If I get on it and then lift and leave it in gear to cost the pressure will rise to 60 psi slowly untill I touch the gas.

What's up with that? is that normal?

 

[errray's 03 svt]

@ idle about 30
@ wot about 55-60
atleast that's where mine is at.

 

[02yellowgt]

Mine also will dip below 20 after lifting @ WOT. If I get on it and then lift and leave it in gear to cost the pressure will rise to 60 psi slowly untill I touch the gas.
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What's up with that? is that normal?

 

[§ilver§nake]

These deviations are normal. The CPU is programmed to maintain an A/F ratio of 14.3 to 14.7 while in Closed Loop mode (not WOT). It does this by regulating the fuel pressure based on readings from, among others, the TPS.

On the other hand, in Open Loop mode (WOT), the CPU is programmed to get the A/F ratio below 12.5; to do this, the engineers decided to feed the engine at 60 or so psi of fuel pressure. Depending on your location, you may have an A/F ratio of 12.5 while others experience a "pig rich" condition of 10 or 11.

 

[02yellowgt]

Thanks, I wonder if this is my problem. I open track my car and most of the time the car is at w.o.t. I lift of course going thru turns and when exiting turns I go back to WOT. I'm getting big hesitiations when going back to wot it hesitates then grabs and goes. sometimes it can take up to a few good seconds to get the car to return to making boost. or I have to blip the throttle a few times then it grabs almost like it 's starving for gas.

 

[§ilver§nake]

I'm not an Open Track guy only because I just don't have the time. However, I think you could be experiencing a temporary starvation for fuel because, unless the tank is full, the gas has shifted to one side of the tank while you are making the turns. If, on the other hand, this is not the case, then you should look into the AfterBurner along with an Wideband O2 sensor. This will allow you to get real world A/F readings and adjust the fuel pressure accordingly.

 

[02yellowgt]

, then you should look into the AfterBurner along with an Wideband O2 sensor. This will allow you to get real world A/F readings and adjust the fuel pressure accordingly.

Thanks for the info. I'm thinking that fuel starvation is the problem also. What would be the best place to get something like you listed above.

 

[§ilver§nake]

This is what I use for Fuel Pressue control (click here) This unit intercepts the Fuel Pressue signal coming from the PCM and either multiplies it or divides it, depending your choices. The software is very easy to use and allows modifications in 200 RPM increments, allowing you to flatten the A/R ratio fairly well.

Here is a sample reading using my Winter configuration:

I don't have my Spring configuration fine-tuned yet.

This is the Wideband O2 sensor I use. (click here) They are expensive relative to others on the market; but I have been quite pleased with the performance and support I get. Also, this package interfaces with the unit above, allowing me to get real-time readings from within the AfterBurner software.

I hope this helps.

 

[Justin Blake]

At idle my gauge reads-50. Normal driving-60. Wot- 75-80. But you know whats going on with my car.