Accel AFPR Weirdness
Thread Starter
Team Owner
Joined: Sep 2002
Posts: 22,209
Likes: 12
From: OBAMA IS HITLER
Accel AFPR Weirdness
I could have sworn I had a bad fuel pressure regulator in my Accel unit. Approx. 2,500 miles on it. My homespun observations:
Vacuum test: failed. This is where you take a vacuum test gage, hook the hose to the nipple on the FPR and see if it holds vacuum. It did not - at all.
Fuel pressure test: passed, but with qualification. Held pressure steady but the AFPR could not be adjusted lower than 53psi with vacuum line disconnected. This left fuel pressure too high.
Fuel leak test: failed. Visual inspection revealed a very slight amount of fuel spritzing from the FPR nipple at idle. No fuel in oil pan after 2 short interval oil changes (200 miles apart).
So we say we have a bad AFPR.....right? The strange thing here is that when the Accel unit was removed, there was NO damage to the diaphram, at least it couldn't be seen. This seems weird.
With the new Holley AFPR, it passes the fuel pressure (holds a nice steady 43psi w/line disconnected) and fuel leak test......All seems fine.......EXCEPT it doesn't hold any vacuum either! This seems weird too.
What is going on? Do I need more beer? This all makes no sense to me.
Vacuum test: failed. This is where you take a vacuum test gage, hook the hose to the nipple on the FPR and see if it holds vacuum. It did not - at all.
Fuel pressure test: passed, but with qualification. Held pressure steady but the AFPR could not be adjusted lower than 53psi with vacuum line disconnected. This left fuel pressure too high.
Fuel leak test: failed. Visual inspection revealed a very slight amount of fuel spritzing from the FPR nipple at idle. No fuel in oil pan after 2 short interval oil changes (200 miles apart).
So we say we have a bad AFPR.....right? The strange thing here is that when the Accel unit was removed, there was NO damage to the diaphram, at least it couldn't be seen. This seems weird.
With the new Holley AFPR, it passes the fuel pressure (holds a nice steady 43psi w/line disconnected) and fuel leak test......All seems fine.......EXCEPT it doesn't hold any vacuum either! This seems weird too.
What is going on? Do I need more beer? This all makes no sense to me.
Last edited by Red Tornado; Jun 15, 2005 at 12:56 PM.
Team Owner
Joined: Jan 2003
Posts: 20,299
Likes: 240
From: Summerland B.C. Canada
Call me crazy but how could it hold vacuum. Isn't the nipple on the top side of diaphram in the bonnet. Isn't the adjuster threaded into the bonnet without any true seal to totaly stop air from being taken in past the threads. 
Thread Starter
Team Owner
Joined: Sep 2002
Posts: 22,209
Likes: 12
From: OBAMA IS HITLER
guys, you have a great point, which had me baffled all along. out of 5-6 folks i talked to, half said it should hold vacuum, the other half couldn't figure out why i would apply a vacuum gage to it in the first place.
since the accel unit couldn't hold fuel pressure below 53 psi (it was the correct one for L98), i considered it faulty, especially since a little fuel leaked from the metal nipple......the strange thing still holds that the diaphram appeared perfectly normal.
even so, summitracing agreed to take it back for a full refund.
no matter, i'm more than pleased with the holley unit - this thing is a helluva nice piece
since the accel unit couldn't hold fuel pressure below 53 psi (it was the correct one for L98), i considered it faulty, especially since a little fuel leaked from the metal nipple......the strange thing still holds that the diaphram appeared perfectly normal.
even so, summitracing agreed to take it back for a full refund.
no matter, i'm more than pleased with the holley unit - this thing is a helluva nice piece
The Holley unit is faaaar better. 
