walboro255, 450cc, safc2...POSITIVE correction?! - 3000GT/Stealth International Message Center

Cobane · 06-26-2008, 11:04 AM

ok so i just finished installing walboro 255, and some 450cc injectors. I preset all the corrections on my SAFCII down to -20% as a starting point to compensate for the bigger injectors.

The car barely ran at these settings, way too lean. I got all my O2's to cycle in open loop at ab out +3-5% correction, so right away i know something is not right. And to add, in closed loop as soon as i get near boost it leans way out even with SAFC cranked to +20% (i realize this is way off)

I pulled the pump to see if it was leaking and blowing back into the tank. It was slightly loose and i remounted it using 2 orings to get everything nice and snug (even with both plastic pieces and a new oring, theyre was gap on the nipple coming out of the pump, but no longer after adding a second oring as a spacer)

electrical wise, all the connections seem ok except for a slightly exposed and frayed wire the thin one wraping around the arm that goes to one of the floats.
my fuel gauge is completely off and shows empty light always, reading 3/4 full with maybe 4 or 5 gallons in it (which im assuming is that wire) but as far as the actual wires powering/grnding the pump, theyre solid.

dont have a fp gauge or regulator so i cant be sure, but visual inspection shows no reason for fuel pressure to be low at the rails.

92rtawd · 06-26-2008, 12:29 PM

Did you reset the ECU when you installed the AFC? What are your fuel trims?

Cobane · 06-26-2008, 12:38 PM

i installed the AFC a few weeks ago, and got it "tuned" running correctly for stock fuel before installing the injectors/pump. dont think that is the problem.

dont know the trims, logger hasnt come in yet so im prtty much just using a NB a/f gauge. i know this is a horrible idea but it shouldnt have been a problem as i wasnt going to up the boost and really tune it, just trying to get it running correctly at 8-10psi.

lawdogg · 06-26-2008, 01:00 PM

Have you pressure tested? I had a similar problem when I forgot to re-tighten my lower plenum bolts.

Cobane · 06-26-2008, 01:16 PM

no pressure tested, but just because you said that i wen and checked all the plenum bolts and the 3 middle bolts are all completely stripped (thats what i get for letting a friend help putting things back together to save time)

well this sucks gotta tap the lower manifold with some new threads i guess, mite try getting some new bolts that i could just crank in there to tighten it up for the time being as im going to have to tap them anyway.

how likely do you think it may be this causeing my fuel issue?

lawdogg · 06-26-2008, 01:19 PM

Pretty freaking likely. With a vac. leak:

Under vacuum the engine sucks in too much air. It goes lean and you need more + correction.

Under boost the engine blows out air, and it goes rich.

Cobane · 06-26-2008, 02:38 PM

Its insanely lean in boost.

Cobane · 06-26-2008, 02:41 PM

completely misses and doesnt continue to accelerate or even run if it gets close to boost, it just cuts out seemingly when i hit closed loop and "bogs" trying to shut down until i let off the gas.

92rtawd · 06-26-2008, 10:15 PM

Quote:

Originally Posted by Cobane

Its insanely lean in boost.

How sure are you that the injectors are good? Were they flow tested?

A boost leak would cause you to run rich. The only thing I can think of other than prior fuel trims would be if your injectors are clogged.

lawdogg · 06-27-2008, 04:12 AM

Quote:

Originally Posted by Cobane

Its insanely lean in boost.

Hm.

Only other thing I can suggest is to double check your MAS. When the webbing in mine popped out, it did something similar.

06-26-2008, 11:04 AM	#1 (permalink)
Cobane Forum Member Join Date: Apr 2004 Location: Sutton, MA. Drives: nope, mostly towed Trader Rating: (8)	walboro255, 450cc, safc2...POSITIVE correction?! ok so i just finished installing walboro 255, and some 450cc injectors. I preset all the corrections on my SAFCII down to -20% as a starting point to compensate for the bigger injectors. The car barely ran at these settings, way too lean. I got all my O2's to cycle in open loop at ab out +3-5% correction, so right away i know something is not right. And to add, in closed loop as soon as i get near boost it leans way out even with SAFC cranked to +20% (i realize this is way off) I pulled the pump to see if it was leaking and blowing back into the tank. It was slightly loose and i remounted it using 2 orings to get everything nice and snug (even with both plastic pieces and a new oring, theyre was gap on the nipple coming out of the pump, but no longer after adding a second oring as a spacer) electrical wise, all the connections seem ok except for a slightly exposed and frayed wire the thin one wraping around the arm that goes to one of the floats. my fuel gauge is completely off and shows empty light always, reading 3/4 full with maybe 4 or 5 gallons in it (which im assuming is that wire) but as far as the actual wires powering/grnding the pump, theyre solid. dont have a fp gauge or regulator so i cant be sure, but visual inspection shows no reason for fuel pressure to be low at the rails. __________________ FWD TT Swap 450cc's Maximal Mounts SAFCII MSD's Walboro255 IPO DSMBC ESP downpipe Intrax Gutted cat 18" Saleens

06-26-2008, 12:29 PM	#2 (permalink)
92rtawd Rock Chalk, Jayhawk Join Date: Dec 2003 Location: Bloomington, IN Drives: 92 Stealth TT Trader Rating: (6)	Re: walboro255, 450cc, safc2...POSITIVE correction?! Did you reset the ECU when you installed the AFC? What are your fuel trims? __________________ AIR: WRX 13T turbos, Greddy FMIC, K&N Filter, A'pexi twin chamber BOV, Greddy Profec B, ESP downpipe, IPS single shot catback FUEL: Greddy E-Manage,Walbro 255lph pump, IPO hotwire kit, AEM AFPR, 450cc injectors SPARK: MSD wires, NGK plugs DRIVETRAIN: PST 2-piece CFDS, Centerforce dual friction clutch

06-26-2008, 12:38 PM	#3 (permalink)
Cobane Forum Member Join Date: Apr 2004 Location: Sutton, MA. Drives: nope, mostly towed Trader Rating: (8)	Re: walboro255, 450cc, safc2...POSITIVE correction?! i installed the AFC a few weeks ago, and got it "tuned" running correctly for stock fuel before installing the injectors/pump. dont think that is the problem. dont know the trims, logger hasnt come in yet so im prtty much just using a NB a/f gauge. i know this is a horrible idea but it shouldnt have been a problem as i wasnt going to up the boost and really tune it, just trying to get it running correctly at 8-10psi.

06-26-2008, 01:16 PM	#5 (permalink)
Cobane Forum Member Join Date: Apr 2004 Location: Sutton, MA. Drives: nope, mostly towed Trader Rating: (8)	Re: walboro255, 450cc, safc2...POSITIVE correction?! no pressure tested, but just because you said that i wen and checked all the plenum bolts and the 3 middle bolts are all completely stripped (thats what i get for letting a friend help putting things back together to save time) well this sucks gotta tap the lower manifold with some new threads i guess, mite try getting some new bolts that i could just crank in there to tighten it up for the time being as im going to have to tap them anyway. how likely do you think it may be this causeing my fuel issue?

06-26-2008, 01:19 PM	#6 (permalink)
lawdogg Here for the tuna. Join Date: Jul 2003 Location: Williamsport, PA Drives: The Speed Limit Trader Rating: (61)	Re: walboro255, 450cc, safc2...POSITIVE correction?! Pretty freaking likely. With a vac. leak: Under vacuum the engine sucks in too much air. It goes lean and you need more + correction. Under boost the engine blows out air, and it goes rich.

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06-26-2008, 02:38 PM	#7 (permalink)
Cobane Forum Member Join Date: Apr 2004 Location: Sutton, MA. Drives: nope, mostly towed Trader Rating: (8)	Re: walboro255, 450cc, safc2...POSITIVE correction?! Its insanely lean in boost.

06-26-2008, 02:41 PM	#8 (permalink)
Cobane Forum Member Join Date: Apr 2004 Location: Sutton, MA. Drives: nope, mostly towed Trader Rating: (8)	Re: walboro255, 450cc, safc2...POSITIVE correction?! completely misses and doesnt continue to accelerate or even run if it gets close to boost, it just cuts out seemingly when i hit closed loop and "bogs" trying to shut down until i let off the gas.