Adjustable Fuel Pressure Regulator
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Team Owner
Joined: Apr 2000
Posts: 27,818
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From: CT
Adjustable Fuel Pressure Regulator
I am now wondering if my AFPR has flown the coop. We just did a check and when disconnecting and re-connecting the hose(We did it on another car for comparison and it shot up nicely.. Mine doesn't) it doesn't re-act like it should. Could the diaphragm have gone bad since 1997? That's when LPE put it in. Pressure seems a little above 50 with it off and around 49-50(it was dark) with it off.
Is it worth putting in a new one just in case? I think it's an Accel unit. Thanks in advance.
Is it worth putting in a new one just in case? I think it's an Accel unit. Thanks in advance.
Melting Slicks
Joined: Aug 2001
Posts: 2,047
Likes: 0
Re: Adjustable Fuel Pressure Regulator (JD 90 383)
You can similulate the operation of the motor vacuum with one of those handy dandy "Mityvac" devices. My advice would be to have the car running at idle, disconnect the vacuum line from the regulator and reconnect the "Mityvac". You should be able to draw down the pressure on an almost incremental basis. 1" of vacuum should equal about 1 lb of fuel pressure (change). I would definitely put the car on a dyno with data acquisition capabilities and tune the fuel pressure while monitoring the A/F ratio. It is very difficult to get an accurate setting without doing the A/F testing. You'd be surprised... tweaking it just right will swing your peak hp by + or - 10 hp... maybe more if you're waaay of to start. While it's on the dyno, you can also make sure that the fuel pressure doesn't drop dramatically while running the car under load... One of the nice features on the newer versions of the "Dynojet" software is that you can "brake" the car at certain RPM or speed levels to do some "under load" type of testing and calibrations. You'll spend more on the dyno testing than the new fuel pressure reg so it may pay to do the Mityvac testing first.
[Modified by EricVonHa, 2:00 AM 9/1/2001]
[Modified by EricVonHa, 2:00 AM 9/1/2001]
Race Director
Joined: Aug 2000
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Cruise-In II Veteran
Re: Adjustable Fuel Pressure Regulator (EricVonHa)
Hey dude,
a ruptured diaphragm would probably cause fuel to leak out the vacuum port connection on it.
Check for fuel in the line or it spitting out when running.If any fuel is present, you have a bad FPR.
Also ericVon seems to have good suggestions.Try them out as well if possible in your area.
Ive always wondered where people went to get tuned on a dyno...Ive asked around places before where I could find a dyno and people looked at me like I had 3 heads.
Seem the only places I could find one was a 200 mile drive or more.
Good Luck and let us know how you make out.
a ruptured diaphragm would probably cause fuel to leak out the vacuum port connection on it.
Check for fuel in the line or it spitting out when running.If any fuel is present, you have a bad FPR.
Also ericVon seems to have good suggestions.Try them out as well if possible in your area.
Ive always wondered where people went to get tuned on a dyno...Ive asked around places before where I could find a dyno and people looked at me like I had 3 heads.
Seem the only places I could find one was a 200 mile drive or more.
Good Luck and let us know how you make out.
