550s leaning out, need help!

[suprafanatic]

so i installed 550 injectors and the lex afm. i also have a wideband and safc II.. when i boost in first gear it runs somewhat rich then as it hits higher rpms it leans out. it does this is first and second gear. in 5th gear if im at WOT the wideband shows a flat 10. so its leaning out in lower gears, but rich in higher gears. what would cause this? or what can i do to fix this problem? i have the afm screw in as far as it will go. Also im only boosting around 12-13psi.

 

[black91turbo]

Yeah i had the same problem with my LEX and 550 combo......I couldn't figure it out and just bought the maft-pro. Everything is fine now. :dunno: Do you have a walboro and a FPR?

 

[suprafanatic]

UGH!! lol.... i was running my stock injectors and the lex afm and it never leaned out like this.. does anyone know what is happening? and yes i have a Walbro, but no FPR

 

[Quin]

Yes Walbro, no AFPR.

 

[suprafanatic]

would getting a AFPR fix this problem? or does anyone think it could be something else? cause its running really rich in higher gears, just not in first and second.

 

[Koenigturbo]

Double response, see below

 

[Koenigturbo]

Sorry I don't have an answer, but I have qeustion on top of this qeustion:

It's a real mystery to me why some of our cars react differently with the same mod. All our cars should the same from the factory then why are we getting different results from our mods?? I have the exact opposite problem. Makes me wonder if we are fully disclosing what mods we have when we write our threads or mods have been done without prior knowledge. You would think it would straight forward, if you do a mod to a car then all our cars should should react the same way, but no,.. seems like it's different from one car to another.

 

[wardog]

You should start with an Aeromotive afpr and drill out the whole in the fuel hard line under the alternator. Maybe your stock fpr is going out, i would start there. You got any codes ?

 

[Koenigturbo]

You should start with an Aeromotive afpr and drill out the whole in the fuel hard line under the alternator. Maybe your stock fpr is going out, i would start there. You got any codes ?

Talking to me?? If you are, I don't have any codes

 

[black91turbo]

You should start with an Aeromotive afpr and drill out the whole in the fuel hard line under the alternator. Maybe your stock fpr is going out, i would start there. You got any codes ?

Or you could just bypass the jtube.....which would be about 100% easier.

 

[7Mboost]

I assume you've taken fuel out with the SAFC in higher gears? The wideband sensor good?

 

[suprafanatic]

well you cant just take out fuel in higher gears can you? i thought you could only go by rpm range?? also i have drilled out the Jtube already.. i guess my next step would be try a fuel pressure regulator.. i really dont have the money right now though, guess i'll just be easy on her for a while. UGH.. and as far as i know the wideband sensor should be just fine.. its not very old,,, what are the chances of it going bad?

 

[suprafanatic]

oh, sorry forgot to answer... no codes either

 

[suprafanatic]

ok so the car is now fixed and its faster than ever... i had a replica spearco intercooler and coolez pipes laying around so i decided to finaly put it all on.. my car is no longer leaning out in 1st and 2nd gear, and it fixed my boosting problem, before my car would bost like 15 then drop to 11.. now it holds 15 solid... now its running rich so i need to tune it.

 

[WhtMa71]

You still need to at least get a fuel pressure gauge kit so you know what your fuel pressure is.
When you installed the walbro did you do the 12volt mod?

 

[suprafanatic]

no i didn't do that 12v mod.. why is that so important?

 

[WhtMa71]

It's not that important, but its something good to do when you install the walbro just to ensure you're getting all 255lph the pump is rated for. Call it peace of mind.

 

[grimreaper]

^^ the pump goes 12v when your at wot, im confused to why it matters when your in closed loop, obviously Toyota didnt think it did

 

[figgie]

^^ the pump goes 12v when your at wot, im confused to why it matters when your in closed loop, obviously Toyota didnt think it did

correct......

but only in a specific window of OEM operations on an OEM motor.

With that said, how does the fuel pump circuitry do the switching? Do it actually switch or bypass? yes there is a difference. Switching will causes a momentary loss of power to the fuel pump. Bypassing will not.

and looking at the TEWD

http://www.cygnusx1.net/Supra/Library/TEWD/MK3/manual.aspx?S=Main&P=46

it switches. This is NOT good on a high output fuel pump as during the switching it will cut power for an instant before the full power is applied. This is not PWM folks!

 

[grimreaper]

good stuff, wonder why a few of the old timers say its one of the dumber mods ?

figgie, do you know if the fuel pump switches to 12v on start up or possibly when the motor is cold enough to warrant the warm up cycle?

im dgging through the manual but i cant find anything that says when and at what parameters the pump runs on 12v