Bought an AFPR - how to adjust?
Thread Starter
Burning Brakes
Joined: Jun 2003
Posts: 846
Likes: 105
From: Knoxville TN
Bought an AFPR - how to adjust?
Just like the topic states. I bought a Holley AFPR, was wondering what was the correct way to adjust, and how much pressure should I go with stock internals, and the stock intake? Thanks for all the help and answers. 
Safety Car
Joined: May 1999
Posts: 3,651
Likes: 5
From: Atlantis
Cruise-In I Veteran
Adjusting it by the buttometer method isn't very useful.
The correct way is to scan or get someone to scan your ECM data and determine which way you need to adjust it, pressure up or down.
BTW..an AFPR is a VERY BLUNT scapel.
It's a ROUGH adjustment to values that need to be 'fine' tuned.
It's mainly for making wholesale fuel pressure changes that affect your BLM and INT values.
Problem is it is 'difficult' to get it right on one 'end' or the other without adversely affecting the oposite end of the fuel flow.
Adjusting it without knowing which way you're trying to go is like driving with a blindfold on.
If you aren't ready to scan and burn your own, I'd reccomend you get a fuel pressure gauge connected to the fuel pressure test port and adjust it to the stock value; 40 to 45 PSI.
Leave it there until you're prepared for the REAL 'stuff'.
After you are burning your own chips you'll realize you didn't need it in the first place.
The correct way is to scan or get someone to scan your ECM data and determine which way you need to adjust it, pressure up or down.
BTW..an AFPR is a VERY BLUNT scapel.
It's a ROUGH adjustment to values that need to be 'fine' tuned.
It's mainly for making wholesale fuel pressure changes that affect your BLM and INT values.
Problem is it is 'difficult' to get it right on one 'end' or the other without adversely affecting the oposite end of the fuel flow.
Adjusting it without knowing which way you're trying to go is like driving with a blindfold on.
If you aren't ready to scan and burn your own, I'd reccomend you get a fuel pressure gauge connected to the fuel pressure test port and adjust it to the stock value; 40 to 45 PSI.
Leave it there until you're prepared for the REAL 'stuff'.
After you are burning your own chips you'll realize you didn't need it in the first place.
Team Owner
Joined: Dec 2000
Posts: 90,675
Likes: 304
From: SE NY
Cruise-In II Veteran
The place to start is with your stock FP setting. Before you install the AFPR measure and record this value for the stock FPR at idle with the vacuum line disconnected.
After the AFPR is installed bump fuel pressure 4psi at a time and check performance. Once performance noses over back off 2psi. You can use trap speed, G-Tech data or a dyno to measure performance at WOT.
When you have completed tuning as above, use the Field Test mode on my site to verify that the ECM is still maintaining proper A/F at idle and part throttle.
BTW, since an AFPR is typically used to tune fuel flow at WOT to match air flow increases due to mods, what other mods do you have in addition to the AFPR you will be adding?
After the AFPR is installed bump fuel pressure 4psi at a time and check performance. Once performance noses over back off 2psi. You can use trap speed, G-Tech data or a dyno to measure performance at WOT.
When you have completed tuning as above, use the Field Test mode on my site to verify that the ECM is still maintaining proper A/F at idle and part throttle.
BTW, since an AFPR is typically used to tune fuel flow at WOT to match air flow increases due to mods, what other mods do you have in addition to the AFPR you will be adding?
Thread Starter
Burning Brakes
Joined: Jun 2003
Posts: 846
Likes: 105
From: Knoxville TN
Originally Posted by 65Z01
When you have completed tuning as above, use the Field Test mode on my site to verify that the ECM is still maintaining proper A/F at idle and part throttle.
BTW, since an AFPR is typically used to tune fuel flow at WOT to match air flow increases due to mods, what other mods do you have in addition to the AFPR you will be adding?
BTW, since an AFPR is typically used to tune fuel flow at WOT to match air flow increases due to mods, what other mods do you have in addition to the AFPR you will be adding?
Last edited by da6speed; Sep 15, 2004 at 11:02 PM.
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