How do I adjust my fuel pressure on my 91z28? i just installed the adj. one and now I need to know the steps to take to do the adjusting.

 

You'll need a fuel pressure gauge and a screw driver to turn the adjustment screw on the FPR. Plug the fuel pressure gauge into the schrader (SP?) valve that is on the passanger side fuel rail towards the back. Disconnect the vacume line from the fuel pressure regulator. Start the car, and use the adjustment screw to set the pressure. Stock should be around 42 psi (I'm pretty sure!)


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Corry Lazarowitz
clazarow@voicenet.com
clazarowitz@hotmail.com
1987 Pontiac Trans AM (GTA?) 350 or is it a 305?! TPI
SLP 1 3/4" headers, 3" cat back (stock cat
MSD ignition.
MSD Blaster SS coil.
3.73 Rear end gears
Accell 8.8 Wires
Bosh +4 Spark Plugs (Don't know if they really help but hell!)
Holley AFPR
Race Built Automatic trans ('vette servo, shift kit, tightly packed clutches)--just needs titanium gears now!
Newly gutted cat (the car gutted it's own cat!)
Hypertech Chip (Just found out I had it! :eek
More soon when funds are avail...

 

yea.. 42 is stock. turn it up to 46 or a little higher. post again and tell if you can notice any difference. There is supposedly a big hp gain to be had by doing this, but i wanna hear it strait from someone who does it.

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• 83 Z28--ttops, 200k miles--very ragged out. sold, thank goodness
• 74 Z28--slightly modded 383, TH400 tranny, not too quick but fun to drive

 

i will let you all know the gain i get from adjusting it this weekend

 

As per the FAQ page:
Q: How do I correctly set the fuel pressure on my new adjustable fuel pressure regulator?

A: The correct way to adjust your fuel pressure is with the vaccum line of the fuel regulator disconnected. The instructions with many adjustable fuel regulators don't tell you to do this, but it is essential! You must remove and plug the vaccum line going to the regulator or you will be getting false readings, similar to adjusting the timing on vacuum advance distributor. What you are attempting to do is set the maximum fuel pressure. At idle, fuel pressure is reduced due to high vacuum, so the presence of the vacuum line is detremental to fuel pressure. Repeat the process until you have the desired reading.

 

So do you pull the vac line off the plenum and plug the end so its the regulator that has no vac leak but the plenum is still open. Or do you pull the vac line off the regulator and plug it so the plenum is sealed and the regulator is sealed???????

 

You want to plug the plenum, so that you do not have a vacume leak, but the FPR isn't being effected by vacume