View Full Version : fuel pressure tuning

05-09-2004, 10:36 PM
so the buschur/sx afpr is goin in tomorrow and i was wonderin if u guys could give me some useful tips for tuning fuel pressure since ppl on dsmtalk usually are of no help. lol

05-10-2004, 07:16 AM
when you get everything installed start by making sure the car will run. then have someone else help you. take off the vacuum line to the back of the regulator. if you dont have anyone to help plug up the line with something. start with at least 38 psi of fuel. buschur recommends 40psi of base fuel. my car is set at 40. also when you adjust it listen for the motor to run smoother. you can see it stop shaking and just run better be turning up and down. make sure you have the vacuum line off and plugged though. or the fuel gauge wont read right. sorry i never got to call or email you. ive been sick for about a week. if you have trouble figuring things out call me. its reall simple. its only two 10mm bolts for the regulator, and the gauge just screws on top of the fuel filter.
good luck

05-10-2004, 07:33 AM
43psi on a 2g, with no vacuum. (just incase since you didn't list the car).It should read about 38-39psi with the lines hooked back up. If you have a TMO/DSMLink, use the fuel pump feature to run the system with the car off to make sure there are no leaks.

05-10-2004, 09:44 AM
car is a 93. he only has an AFC.

50Trim Boy
05-10-2004, 09:56 AM
I hope you have some sort of fuel pressure gauge... I'd say right around 40psi for the base pressure... (vacum line off ofcourse)

05-10-2004, 11:17 AM
holy **** the car runs so much better now. lol. i didnt mess w/ it too much, just set the base fuel press. at 40 like steve said, could use some more tweaking.

its a 92 w/ 680s, afc, walbro 255, and now the afpr

05-10-2004, 11:23 AM
That's because you're no longer over running your FPR :) I run 43psi base fuel pressure. Keep in mind that the majority of injectors are rated at XXXcc/min @ 3 bar (43.5psi) fuel pressure. So if you turn down your pressure to 40psi then you're loosing 7% flow, so tune like they were 7% smaller injectors. Yes this counts for the 1G's too. Just because they came from the factory with a lower base fuel pressure doesn't mean that injectors put into them are right. Actually on a stock FPR larger injectors on a 1G flow less because of the lower setting.

05-10-2004, 08:01 PM
did notice that. thanks again. its nice to not spew fuel... lol too
bad i work til thursday and cant go put plates on it.
the change was pretty obvious too. now it will consistantly start/idle properly and run LOADS better before engine is @ operating temps. now all i need is plates, and free time to really tune it. working 2 jobs+school sucks!