I have a walbro 255LPH HP fuel pump with B&M FPR set to about 45 PSI static fuel pressure, running on DSM 450CC Injectors. Most people's settings even with wideband are still in the -30's somwhere. But when I installed my wideband, I found even at -30 I was slightly lean. I have to have mines at about -25 to -27 depending what RPM just to get a nice 11.5ish A/R! WTH? If I use other people's settings liek -35. It will run me quite lean in boost. Sure I'll jstu keep it at the settigns now, but I'm just boggled to why I have to dump the fuel in to get the same A/F ratios as others with teh exact same setup... Why would I have to dump fuel in like that...

Also what I noticed was that after I installed my fuel pump, the car seemed to run leaner and what not judging by my crappy narrowband A/F guage.(no wideband at that time) As some of you know, the problem with B&M and Walbro is that your fuel pressure sky rockets because the stock regulator cannot return the fuel fast enough but what I noticed was that I am still able to fully adjust my B&M down to 35PSI(maybe even lower) if I wanted without a problem...? I'm just wondering if maybe my injectors are just in need of cleaning, or maybe my fuel pump is bad or something... I don't see how I can adjust my fuel pressure below the given amount taht most people CAN'T adjust below with the walbro and B&M.. So i was thinknig maybe my Walbro isn't providing enough volume but enough to register full fuel psi?? Any ideas? Sry for the long post haha.

Also, yes I know what the AFC does to timnig, I have a custom chip made with the ignition table replotted to somehwat balance it out. But that's for -40% correction, so anything less, like -25 is just retarding my ignition now so it's on the safe side. Also have 1 degree retard per boost.

 

I was just about to answer your question... but you lose me somewhere between the worlds longest run-on sentence and poor spelling/grammar.

It's ok to use punctuation.

By the way, 11.5:1 afr is not lean.

 

I just corrected the grammer errors whiel you posted that hahaha


I was mroe saying it was lean at the -30 setting.. if I had it set to -35 liek alot of peiple. it runs me in the 13's... in boost

 

ummm, when was the last time you changed the fuel filter? that might be your problem...i know that was mine...

 

Hrm.. Prolly not for about 1 year now. I was going to change it at the same time but I totally forgot. I'll do that this weekend thanks.

 

all you need to do is watch the fuel pressure while you are in boost. see if it holds. if it doesn't, you've got a pump taking a **** or you have a clog somewhere.

 

maybe your injectors are clogged up and not flowing a full 450.

 

Damn.. I don't have a incar fuel pressure guage. only under hood one. maybe I'll buy a cheapo one to temporarily rig up in the car for testing as I don't really have anymore room for guages in my car I'm going to change the fuel filter soon. My old setup was practically the exact same thing but then the oil pump took a poop. while it was down, is when I isntalled the new walbro 255 and reused all other old fuel etc stuff so I was thinknig maybe the pump was defective cause that's all I changed.

 

Ive got a similar problem, what sorted it out in the end

 

Ive got a similar problem, what sorted it out in the end

 

never fixed it. jsut kept my base fuel pressure at 42-43ish and about 50 WOT. Tuned my setup from there and runs fine

 

do u have stock internals and what kind of boost u running???

 

sotkc b16 with ARP head studs. 10.5 psi on SC34