fuel issue -running lean

[H4G64T]

car runs lean?? why?? any ideas. its got a manually wired 255 lph fp (bypasses ecu). adjustable fpr set at 40 psi on idle. 450cc injectors with resistor box. the a/f gauge is reading lean and the exhaust even in boost doesnt even have an odor of fuel. any ideas please??

 

[ilco187]

stock or aftermarket o2 sensor?

 

[PIMking]

Probably because your narrow band sucks and its lying to you. Get a real wideband and report back.

 

[H4G64T]

yeah, let me just whip out 220$ and just plop it right in. awesome.

anyone else that actually has something useful to say?

brand new oem replacement o2 for a gst is in it right now.

 

[ilco187]

is it a wideband air/fuel gauge, does it stay lean all the time, does it even move "at all" while driving, did it show anything before, im thinking it might not be wired correctly, when did you put it in, did you do something and then it just started reading lean, or did this happen out of the blue.

 

[leepen]

yeah, let me just whip out 220$ and just plop it right in. awesome.

anyone else that actually has something useful to say?

brand new oem replacement o2 for a gst is in it right now.

Like PIMking said, your flashy light show narrow band is garbage. If you realy want to know what your A/F is whip out the $220 and get something that works. I think this is useful

 

[jeffo]

Do you have a logger? I prefer to check fueltrims to see if the car is too lean in closedloop operation. At idle, and while cruising at light throttle, the O2 voltage should swing back and forth around .45-.50 volts. Are you seeing that?

 

[mikelv]

Please update your profile and mods list. I'm not even sure what kind of car you have.

 

[H4G64T]

its not my car. ive done the same mods to mine years ago, but never had these issues. its a 98 spyder gs with a 2g turbo swap. everythings converted to turbo. my car ran perfect and this kids car is running like crap. ill update more about the car if u need in a bit. im gona test the voltage.

 

[mikelv]

So it's pretty much a 4G63 FWD

What year ECU is it?

Depending on the situation, those stock injectors could be working too hard.

What kind of engine management? If you upgrade fuel components with no way to control them, of course you are going to have problems. The ECU isn't human, it doesn't know that you've changed these parts. It's going to run as if there is the same injector size, same pump size, ect....when you mess with A/F ratios, it's a simple fix, you have to control them. Now if you bypass the ECU, it can't even get any feedback on the pump anyway.
If the car was working fine, rich, but working, then it just stopped, then you should make sure the ground on the pump is good.

If you can get a mods list for the car we might be able to help. Also, some exact details of the symptoms would be helpful. How do you know it’s running lean? What is the car doing exactly? Talk to the kid, or get him on here, and we’ll see if we can help you figure it out.