I just installed a walbro 255 LPH fuel bump in my 99 GSX. I have a turbo back exhaust, big16g turbo and tubular manifold. the car drives fine when not building boost but after it goes above a few psi it starts bogging and hesitating, it also feels like it's lacking power and if I really get on it it will backfire. Am I getting too much fuel or too little? I also clamped the fuel line coming into the fuel rail with a pair of vice grips but I didnt cut it all of the way off, this seemed to help a little but im not positive.

 

you have a fuel pressure gauge? what psi are you running?

 

No I don't, should have gotten one before I know but just didn't think about it

 

If you have the 255, you need an Adjustable FPR. With the 190, you can get by with the stock fpr.

 

stock regulators have worked fine with 255s for 15 years. I don't see them suddenly becoming incompatible.

Did this start only when you changed pumps? If so you either kinked the hose or or the O-ring is not sealing. I doubt it's electrical because a short at the pump will shut the car off electrically.

 

yea it only started after i installed the pump, drove fine before that. it's possible the o-ring isn't sealing because after I installed the pump i found a little plastic spacer on that i guess fell off of the old pump, i wasn't sure exactly where it went on. so basically if the o-ring doesn't seal correctly then I'll basically be running lean right?

well shit, I just paid $120 for a afpr yesterday thinking that was it.

 

i was always told you needed safc for the 255.or dsm link.

but i could be wrong haha. check your install over again then post up your findings. im curious

 

ok I just got done pulling the pump, checked everything, put the spacer in that I forgot last time and put the pump into the housing. this time it felt like it sealed to the o-ring alot better, i took my time and made sure everything looked and felt secure with the pump and housing. everything looked good. so i reinstalled everything and start the car.. this time it reves to about 5 grand on its own when i started it then goes down to about 1 grand boggs a little and dies. i noticed i can keep it running if i keep giving it a little gas but it seems to rev extremely easy now just by tapping the gas. i tried driving it down the road and it didnt seem to bog as much at first but when i gave it a little more gas it backfired like all hell and started stuttering really bad. any ideas anyone?

P.S. - I just picked up a universal AEM AFPR from millenium as soon as i can get a fuel rail with an AN fitting or an adaptor I can install it and try it out.

Also is it possible the motor is dying from running too rich? and only stays running when i rev it because more fuel is required?

P.P.S. - also i noticed this time around the exhaust seemed to pop gurgle and crackle alot more, could be cause it's running so rich right?

 

Safc and tune bro

 

+1 or reinstall stock fuel pump