Adjustable Fuel Pressure Regulator question

plastic_cow

New Member
Sep 10, 2003
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Oshkosh, WI
I have an adjustable fuel pressure regulator (and no fuel pressure gauge...) the directions were vague... to say the least, they stated to set the pressure to 47lbs and adjust from there... so I put it in, fired it up, and it didn't fire up - it pushed so much fuel in that the garage reaked of gas and there was gas coating the plugs and such...
so I let it sit for several hours with some of the plugs out of the engine to let it.. air... but it didn't get quite empty...
Anywho, that's a lot of background for a simple question, if the allen screw is all the way down, is that maximum pressure? because that's what it was set at when I put it in... or is all the way up maximum pressure?
 
Dude, you need a gauge so you can figure out what is going on. Otherwise you are playing pin the tail on the donkey while blindfolded.

I would set my simulated WOT pressure at 39 PSI for starters. Then play with it from there.

Good luck.
 
HISSIN50 said:
Dude, you need a gauge so you can figure out what is going on. Otherwise you are playing pin the tail on the donkey while blindfolded.

I would set my simulated WOT pressure at 39 PSI for starters. Then play with it from there.

Good luck.
:Word: x2
The AFPR I got said it was set to 35 PSI right out of the box. When I started my car, my gauge was reading at 40 PSI at idle and almost 50 PSI @ WOT
:nonono:. AutoZone rents a gauge, use that till you can get one you want.
 
Setting fuel pressure without a gauge is more like playing pin the tail on the needle in a hay stack. Wait, how does that go? I always screw up those expressions.
Renting a gauge is a good alternative, but the cheapest long term solution will probably be a gauge on the schrader valve. Summit would be a good place to start pricing.


Off topic -
I did get your pm about the VC baffle, and will send the pics in the morn.
 
not to steal the topic, but does anyone have a diagram of the afpr and where to usually find the allen bolt hole? my car came with the afpr but im having trouble finding the nut, although i havnt looked to hard yet i just want t know where the general spot is.
 
Also slightly off topic, how effective are AFPRs? I always thought that the computer would adjust your fuel pressure anyway? I know there are limits and whatnot depending on your level of mods, so at what HP level is it advisable to step it up? Also, if I have an autometer fuel pressure guage, will that be the only guage i need?
 
Andres2882 said:
Also slightly off topic, how effective are AFPRs? I always thought that the computer would adjust your fuel pressure anyway? I know there are limits and whatnot depending on your level of mods, so at what HP level is it advisable to step it up? Also, if I have an autometer fuel pressure guage, will that be the only guage i need?
At WOT, the computer goe into open loop and does not use the O2 sensors for fuel managment. The sensors it uses are TPS, MAF, Baro & RPM for a table lookup of how long to pulse the injectors. That means that changes in fuel pressure can change the air/fuel ratio.

Any gauge that is readable and accurate when you need it is good enough. Mine is mounted by the MAF since you can't adjust the fuel pressure while you drive. If there was a good way to adjust the fuel pressure while driving, I would spring for an electric gauge inside the car.
 
The allen screw/bolt is on the opposite side of the connecting end to the fuel rail, usually right by the vacuum connection on the top, directly in the center on most... if you still have problems finding it, pm me and I'll send you a pic of mine