okay on my 2.8 there is an adjustable fuel pressure regulator, 1st question: which way do I turn the adjustment screw on the top to increase/decrease pressure?
what would happen if the pressure was lower than stock? higher? why would I want the pressure higher/lower?
Reducing fuel pressure will make the engine run leaner. More pressure will make it run richer. For all intents and purposes, you're changing the size of your injectors (more pressure = bigger, less pressure = smaller).
In is most always higher, but just increasing the pressure will not make it run richer, the computer looks at the mixture (via oxygen sensor) and adjusts the output pulse width of the injectors to get to it's programmed mixture. There is a fairly wide range of pressures that the computer can work with, higher pressures will allow the computer to keep the proper mixture at higher demands, but there is a limit. If your fuel pressure is within specs then you will end up with proper mixture control. Larry
In open loop mode and PE mode, the O2 sensor is ignored. Fuel pressure will affect fueling during these times.
it wouldn't be a good idea to put it into open loop and take it down the strip a few times, would it?
ALSO, doesn't the 2.8 start to run really rich at high rpm, because the intake cant supply? wouldn't it be better to set the pressure lower in that aspect?
but then again, you said the O2 sensor makes the injectors compensate.
it wouldn't be a good idea to put it into open loop and take it down the strip a few times, would it?
ALSO, doesn't the 2.8 start to run really rich at high rpm, because the intake cant supply? wouldn't it be better to set the pressure lower in that aspect?
but then again, you said the O2 sensor makes the injectors compensate.
Back before ecm tuning was wide spread, after you did some mods you would adjust the fuel pressure to dial in the A/F ratio at WOT (which is also open loop), then let the O2 sensors and the built in BLM feature in the ecms try to keep everything else in check under all other conditions. Tuning is by far the best method, but the adjustable regulator was used as a crutch for quite some time.
The only benifet of installing a fuel pressure regulator is if you are doing modifications to your set-up. For normal driving, it does nothing. I have one on my 88s and a gauge to see the pressure in real time. If you swap in a 3.4PR engine with fiero V6 components maybe you may want to have one. Or a highly modded 2.8l with a turbo, etc.
It depends what you are doing. Day to day driving, keep the stock FPR.