AHHHHHH so my vr4 stumbles and goes lean 99% of the time when I lay into it. Im running 15psi and anything over 1/4 throttle it leans out and stumbles. I am clue less?
Fuel starvation?
I know nothing about VR4’s and what there stock fuel system and stock boost it… but maybe your pushing the motor harder than the fuel system will allow… Sounds like a starvation problem to me
Im not even hitting 15psi i breaks up way before that. Stock is 9.
how do you know it’s lean?
sounds more like a tune problem.
wideband
ok good, wasn’t sure if you were just assuming or actually had to proper tools to read AFRs.
Have you turned boost back down to stock? if so, does it still happen then?
fuel pump good?
stock tune? cold?
It might not be a lean problem. Ignition issues will cause combustion issues and your WB02 readings won’t help.
What’s the status on the plugs/wires?
Turn the boost to WG to reduce the chance of fuel cut and see if it breaks up.
What’s the fuel mods and total mods?
ok i have the stock bcs hooked up so it should be running stock boost. i have a SAFC and for the hell of it made it really rich on my high settings and it did nothing so i took it out. then i played with the timing and the cam sensor is all the way clock wise and it seemed to be better but still stumble and go lean. when i got home i pulled the vacuum line off the fpr and plugged it, at idle it runs right around 14.5 then boosting it it goes in the 13’s but thats still way to lean…
Did you replace the ecu? Is there a boostleak in one of the intercooler pipes?
Whoa.
Do you have a boost gauge?
Why did you take the S-AFC out? What’s your TOTAL mod list including fuel mods?
13 AFR under boost = broken pisting ring landings.
Your tuning is going to be the end of that motor. Do you have a datalogger?
i have 450cc injectors, stock pump, evo3 big 16g hooked up to bcs so it should be running stock boost, SAFC II and i have a wide band. I played with the timing and plugged my AFC back in and it will richen up to mid 11’s now until more that 1/2 throttle. I am going to get a timing light and set my timing, Im thinking thats some of my problem. Also I need to figure out whats causing my CEL, it wouldnt communicate with the computer yesterday.
So, stock fuel?
Why do you need to touch the AFR/TIMING? Why do you need to use a S-AFC?
I’d check the CEL immediately. The answer might be right there. If you have AFR issues with stock fuel/tune, you should pressure test heavily. I still think you have some ignition issues. Your tune should be fine without the S-AFC.
drop a Walbro in, your fuel needs to keep up with those 16G’s
Will the injectors support that? Maybe a hotwired stock pump will work?
Regardless, do they support 16Gs at WG?
Its a galant vr4 only one turbo. My timing is off because I have a ported head that i put on and arp head studs with a MLS head gasket. I have a walbro i need to get it in though. Its not like Im boosting it all over either. I guess Im just going to say for get it and do fuel system now… dammit
Who is doubting the number of turbos?
The timing is off because you have a ported head?
Again, if your AFR is off with stock fuel (which you have), then using a S-AFC to adjust it is a bandaid as there is another probler there.
sully said “those turbos” thinking its a 3000gt with 16g’s