AFPR being inconsistant..

[turboglenn]

I searched for this but found nothing. The last AFPR had on my old motor(aem rail and FPR), i set it, pulled the guage and tuned. Well, this time i bought an Aeromotive and aliquid filled gauge to keep on it at all times and everytime i stop teh car teh guage is reading ~5 PSI different from where i set it.

Example. I set it to ~42 PSI when istalled. On the first test run i felt some lean spots in the map so i threw the laptop and wideband in the car and headed to the highway. By the time i went down town ( about 20 miles) i had lost 5 pounds of pressure. I reset it and went back towards home. When i got home it was 5 psi too high, so i backed it down. The next stop it was back being too low again. SO, i set it once more, finished my tune and went home ( the car is running fantastic by the way ) But i just went to the gas station for smokes and sure enough, 5 pounds too high AGAIN!!!!!!!! arghhhhh

this is really frustrating me, my pump seems to be good. Although it's not holding pressure for more than a few minutes when teh car is off. It should hold almost overnight from everything i learned working at a dealership working ondrivability and startup issues. But, that's not too uncommon on a pump that's got a several years on it as the backflow prevention valve gets worn.

Any ideas on this one? I've never left a guage on one of my own cars to be able to monitor the fuel pressure so often, but this has me concerned that something is wrong, pump or FPR. Could it be that the seat is just "breaking in" on the FPR? Like i said on my last AFPR i set it, took the guage off and tuned.. never checked it again untill i switched pumps and then it needed reset.

 

[fourreGsixty3]

To set fuel base pressure, remove the vacuum line from the fpr and set the pressure to 43.5 psi, then reconnect the vacuum line. Before you set the base pressure, unscrew the vacuum fitting on the FPR and apply tefflon to the threads and reinstall. After you set the base pressure to around 43.5, mark the adjustment rod where it meets the body of the fpr, remove the ajustment rod and wrap a liberal amount of tefflon around and right below the mark, reset your base pressure to 43.5 and make sure the tefflon tape covers the threads between the rod and FPR. Now tighten down the lock nut (be careful not to allow the adjustment rod to move with the lock nut), and leave the fpr alone.

This could be your problem.

 

[turboglenn]

Ahh.. the only part i didn't teflon was the adjustment rod. Never really thought that part needed it. I guess i'll give that a try in the morning and see how it holds through out the day tomorrow.

BTW.. what did you search to find that? I was searching for 'AFPR adjustment issues" "problems AFPR" and similar things.

 

[fourreGsixty3]

Im subscribed to the thread. Heres the link... http://www.dsmtuners.com/forums/newbie-forum/238101-fpr-setting.html

Hope it helps your situation.

 

[turboglenn]

Well, I just tefloned the adjuster rod, hopefully that takes care of the inconsistant fueling. I'll report back when i take her for another drive.

Never mind, found the review i was thinking of writing