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Forum nameTurbo/Nitrous Tech
Topic subjectwtf fp not rising under boost?
Topic URLhttps://forums.2gnt.com/dcboard.php?az=show_topic&forum=i8&topic_id=88357
88357, wtf fp not rising under boost?
Posted by cs82685, Jul-30-05 02:43 PM
Well after thinking my fmu was a piece b/c a/f was lean i set up the sfmu and hooked up a fp gauge, and that didn't help either, fp will not rise over 60-65 psi even under boost. vac lines and fuel lines are not clogged what else could it be?

Could my injectors just be so shitted up they won't supply more than 65 psi or could it be the gsx fuel pump i'm running, those are the 2 things i could think of i was wondering what else (if anything) could it be though?

My next check is to run pressurized air through the vac line to the sfmu and listen for leaks

also i'm a 96 and have the missing link installed
I am in the process of searching too but i figured i could find an answer faster if i could search while people read my post

last thing i'm a friggin idiot b/c i've been lettin it boost for about a week i'm lucky if nothin's f'd up yet
88361, RE: wtf fp not rising under boost?
Posted by extreme97nt, Jul-30-05 06:19 PM
Maybe the gsx pump isnt enough. I would put in a 255lph warlbro. Also what disk are you running?

best time so far 14.3 @ 101.1mph(no traction)
www.cnnmotorsports.com
88368, RE: wtf fp not rising under boost?
Posted by cs82685, Jul-31-05 02:54 AM
largest disk and dark spring
88370, RE: wtf fp not rising under boost?
Posted by sike, Jul-31-05 05:40 AM
I'd say fuel pump also, maybe fuel filter? I'd say pump first though. I had a problem with my walbro255 last week. I couldn't get pressure over 45~50psi with 335cc injectors. I think the prefilter on it may have been clogged, but I didn't take the time to clean it. I just replaced it with a new high pressure walbro. I'll ship you the old one for cheap if you'd want to give it a try, it's an intank. You may want to just try cleaning the prefilter first, and/or replacing the fuel filter if it hasnt been replaced in recent times. I'd also inspect for kinks in the fuel hoses/lines. If the sfmu were leaking boost you would likely see a rise and then drop in fuel pressure but that could also be a sign of a bad pump. If the diaphram were torn your fuel pressure should not adjust at all with boost/vac.
88371, RE: wtf fp not rising under boost?
Posted by cs82685, Jul-31-05 05:49 AM
i checked for leaks and kinks and there are none to be found. simulating at least 7 lbs of boost the fp didn't go over 70 psi so i guess i'm gonna have to try a high pressure walbro 255 and hope that's the problem