Settings for Adjustable Fuel Pressure Regulator?
Thread Starter
Pro
Joined: Apr 2001
Posts: 672
Likes: 1
From: Scottsdale AZ
Settings for Adjustable Fuel Pressure Regulator?
:confused:
For those of you who have an AFPR, how do you set it? What pressure do you use?
We have set ours at 55# peak pressure with vacuum line off and engine off.
We are seeing a surging/hunting with low/no throttle openings. Worse with cruise control on and going down hills. Also noticeable at 40-50 mph and just coasting down.
The only change has been the AFPR settings.
Suggestions or ideas, please?
Instructor
Joined: Sep 2000
Posts: 226
Likes: 0
From: Milwaukee,Wis
Re: Settings for Adjustable Fuel Pressure Regulator? (jimhild)
engine needs to be running
bet your way low on pressure w/engine running. Havent been back to the track to mess w/fuel pressures since reg. went on-its been TOO HOT :mad
bet your way low on pressure w/engine running. Havent been back to the track to mess w/fuel pressures since reg. went on-its been TOO HOT :mad
Heel & Toe
Joined: Jun 2001
Posts: 21
Likes: 0
From: Camp Lester Okinawa Japan
Re: Settings for Adjustable Fuel Pressure Regulator? (SILVER~C5)
I just recieved my afpr in the mail the other day and am going to installit this weekend alon with my new injectors and EGR valve. The consensus that I have heard on the pressure is 42lbs with the engine on and the vacuum line plugged then adjust up and down for best performance from there. you need a minimum of 39 psi with the car off ignition key ot on so the pump is priming the rail. I will let you know how it goes. Also just to let you know, I experienced problems with my EGR valve that caused similar symptoms to yours. Try disconnecting the vacuum line to the EGR valve to make sure that the valve didn't go out. Many times fixing one thing can cause other things to go. So is the nature of the Corvette existence.
Melting Slicks
Joined: May 2000
Posts: 2,974
Likes: 5
From: CenTex Texas
Re: Settings for Adjustable Fuel Pressure Regulator? (jimhild)
First of all the car should be running when you check the fuel pressure. Stock mine was at 59#. After i installed the
AFPR and a GMS MAF and the Vortex i monitored my O2 & KR sensors for a few weeks while the PCM did the re-learn
thing. After fine tunning it i found the optimal fuel pressure to be believe it or not 59#.
AFPR and a GMS MAF and the Vortex i monitored my O2 & KR sensors for a few weeks while the PCM did the re-learn
thing. After fine tunning it i found the optimal fuel pressure to be believe it or not 59#.
Thread Starter
Pro
Joined: Apr 2001
Posts: 672
Likes: 1
From: Scottsdale AZ
Re: Settings for Adjustable Fuel Pressure Regulator? (jimhild)
Thanks for the suggestions. I have raised the pressure some, some of the surging went away, but there is still a lot a no throttle (coast down). BTW, gas mileage went up about 2 mpg with the pressure increase.
Will check the EGR valve tomorrow.
Thanks again, I will take any other suggestions anyone has as a potential solution!
Will check the EGR valve tomorrow.
Thanks again, I will take any other suggestions anyone has as a potential solution!
Drifting
Joined: Dec 2000
Posts: 1,516
Likes: 0
From: Shelton CT
Cruise-In II Veteran
Re: Settings for Adjustable Fuel Pressure Regulator? (jimhild)
Hi there,
First off, if we are talking about your 98, you do NOT have an EGR valve, so dont worry about it.
Next, I would find out what the techs were scanning for. As for the pressure regulator, it will vary, and anywhere between 55-61 will be fine, but nothing higher, or lower.
Is the MAF connected correctly, and was an idle relearn performed??
Has there been any work done on the intake manifold in any way???
There coudl be a myriad of things that could cause this condition.
Please keep us posted, c4c5
First off, if we are talking about your 98, you do NOT have an EGR valve, so dont worry about it.
Next, I would find out what the techs were scanning for. As for the pressure regulator, it will vary, and anywhere between 55-61 will be fine, but nothing higher, or lower.
Is the MAF connected correctly, and was an idle relearn performed??
Has there been any work done on the intake manifold in any way???
There coudl be a myriad of things that could cause this condition.
Please keep us posted, c4c5
Pro
Joined: Aug 2001
Posts: 744
Likes: 0
From: Staten Island NY
Re: Settings for Adjustable Fuel Pressure Regulator? (c4c5specialist)
c4c5specialist,
How far are you from NYC? I'm searching for a dealer I can trust and don't mind the drive a few times a year.
Thanks
Ron
How far are you from NYC? I'm searching for a dealer I can trust and don't mind the drive a few times a year.
Thanks
Ron
Thread Starter
Pro
Joined: Apr 2001
Posts: 672
Likes: 1
From: Scottsdale AZ
Re: Settings for Adjustable Fuel Pressure Regulator? (jimhild)
In reply to c4c5specialist questions:
No mods to the intake manifold. We have the ported MAF from ProAutoTech and a ported Throttle Body from them also, these have been installed over a year before this surging/hunting began, low/no throttle, coast down, cruise control maintaining speed on a downgrade is where we notice this.
The only changes that occurred just before this surging/hunting at low/no throttle began were to replace the initial Donaldson air filter with a Ram Air box from Jake Delaney and the K&N cone shaped filter, adjust the AFPR to 55# peak and add a fuel recurve line for vacuum since the AFPR was connected to the same vacuum line that the original fuel pressue regulator used.
We have done the service manual idle relearn several times, no real changes.
There is no change in the surging/hunting with the vacuum line removed from the AFPR completely. I now have the pressure at 61# peak and about 58# normal.
thanks
No mods to the intake manifold. We have the ported MAF from ProAutoTech and a ported Throttle Body from them also, these have been installed over a year before this surging/hunting began, low/no throttle, coast down, cruise control maintaining speed on a downgrade is where we notice this.
The only changes that occurred just before this surging/hunting at low/no throttle began were to replace the initial Donaldson air filter with a Ram Air box from Jake Delaney and the K&N cone shaped filter, adjust the AFPR to 55# peak and add a fuel recurve line for vacuum since the AFPR was connected to the same vacuum line that the original fuel pressue regulator used.
We have done the service manual idle relearn several times, no real changes.
There is no change in the surging/hunting with the vacuum line removed from the AFPR completely. I now have the pressure at 61# peak and about 58# normal.
thanks
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