ok this problem just started today and at full throttle i am running lean about 15 to 1 when it should be 10 to one here is my set up it might help a little and at part throttl it seems to be ok somewhat

-walbro 255 dont know what one low or high pressure stock wiring
-fuel pressure regulator( tried setting it at 26 psi but doesnt like that low it likes 50 psi +)
-fmu 4:1 did all the calculations
-30lb accel fuel injectors
-t3 turbo
-external wastegate spring at 6psi with mbc at 8 psi
-dumptube to atmosphere might be why its showing lean but losses power
-fmic
-missing link
-safc doesnt seen to do anything
sounds about right if anything seems out of place please let me know i have a couple things thta it might

1 fuel cut ??
2 weak pump
3 pump not enough voltage
4 i have two different style injectors old yellow and black style and the new silver style the guy told me they were the right ones and the were just old and new styles
5 dump tube letting most of exhaust out and the o2 just reading lean
can you guys give me your input thanks matt

start with the easiest thing first, make sure you're fuel pressure is rising under boost b/c 15:1 is absurdly lean for boost

edit, also from what I'm reading you're using an fpr to adjust idle fuel pressure and an fmu to raise pressure under boost? I don't think I've ever heard of anyone using both. How's your setup run? Vac source to fmu and one to fpr? Did this just start happening or did you just install it all and it's running lean?

The more info you can give the more likely someone will be able to point you in the right direction

Originally posted by matty19525
ok this problem just started today and at full throttle i am running lean about 15 to 1 when it should be 10 to one here is my set up it might help a little and at part throttl it seems to be ok somewhat -walbro 255 dont know what one low or high pressure stock wiring -fuel pressure regulator( tried setting it at 26 psi but doesnt like that low it likes 50 psi +) -fmu 4:1 did all the calculations -30lb accel fuel injectors -t3 turbo -external wastegate spring at 6psi with mbc at 8 psi -dumptube to atmosphere might be why its showing lean but losses power -fmic -missing link -safc doesnt seen to do anything sounds about right if anything seems out of place please let me know i have a couple things thta it might 1 fuel cut ?? 2 weak pump 3 pump not enough voltage 4 i have two different style injectors old yellow and black style and the new silver style the guy told me they were the right ones and the were just old and new styles 5 dump tube letting most of exhaust out and the o2 just reading lean can you guys give me your input thanks matt

I have a similar setup but with the SFMU. At 6psi I am seeing around 12's on the wideband. But once I get to 8psi the fuel pressure cranks up around 100+ and I am getting somewhere around 11.8 avereage. And thats at idle fuel pressure of 40psi...

From what i hear, alot of people are having fuel issues using the missing link. Might want to think of replacing that with an electronic fcd if all else fails.

I think we need more detail informations such as what FMU, which spring, what rise rate, which model fuel pump...etc.

Personally I wouldn't be using the SAFC if you have no idea how it works.

I had an issue running low boost, ie 10psi with port fueler system. Every time I engaged boost, a/f gauge would show pegged full rich then start to back down to the lean. I checked everything and finally replaced the o2 sensor and strangely enough, that fixed the whole going lean problem. Now car runs like a champ and pulls hard on boost and no more leaning out problem. Check that. Just a thought...