Car Is Slow and Running Lean!

[MoMo52]

98 gst, just Fmic, Intake and Bov. The car is slow.. got beat by a 420a last night slow.. and is running lean. Timing is good. Boost leak test was done. The car feels faster at half throttle then at full throttle. Turbo spools up quick and healthy.. 02s are good. The only thing he could come up with on the logger was that it is running LEAN. Any ideas?

 

[boostnhard]

98 gst, just Fmic, Intake and Bov. The car is slow.. got beat by a 420a last night slow.. and is running lean. Timing is good. Boost leak test was done. The car feels faster at half throttle then at full throttle. Turbo spools up quick and healthy.. 02s are good. The only thing he could come up with on the logger was that it is running LEAN. Any ideas?

What plugs are you using?
are they gapped correctly?

 

[the_mork]

Check for boost leaks.

 

[MoMo52]

I swapped plugs out and wires. Plugs and wires that is one of the first things i check. Also.. i already checked for boost leaks as i stated above. The car runs the best at about 25% throttle. The harder i hit the pedal the leaner it gets. And for some reason when it runs lean its SLOWWW.

 

[BoostFrenzy]

Is your BOV vented? With your mods, thats the only thing I am thinking could cause it other then something that is malfunctioning.

My thinking is that if it is vented and not properly adjusted it may very well be sucking in air because the spring isn't hard enough or there is a problem with the vacuum line connecting to it. Thing is, it should feel faster and then start knocking from being too lean. And if it is knocking, then it will be pulling timing (which you are saying it is okay). Kinda a paradox...

Could also be the fact that if you are running a stock T25 turbo on a large FMIC then it just runs out of steam and dies off. Also, what are your IDC's?

 

[MoMo52]

what are idc's?

 

[BoostFrenzy]

what are idc's?

Injector Duty Cycle. Basically, what percentage of your injectors are you using up.

 

[MoMo52]

I have no idea. I took it to a guy who owns a shop here called mad dsm. He hooked up his logger and test drove my car. He told me he couldnt remember the last time he drove a car with a t25.. Ne ways. The first thing he went for was the plugs, then wires. Helped a lil bit. then he ran the logger and told me that my car was running lean. He told me to that it might be my injectors. But my car runs and idles perfect. It just consumes alot of fuel and is slow..

 

[BoostFrenzy]

He told me to that it might be my injectors. But my car runs and idles perfect. It just consumes alot of fuel and is slow..

As in "it is running rich" consumes too much fuel or as in "it is lean" from trying to consume too much fuel that isn't there? If it is actually running lean, it shouldn't because you mods are not substantial enough to make it do so. That, and if it was running lean, it would have knock and bad timing.

 

[turboAWDfanatic]

Check your fuel pressure regulator to make sure it is raising the ratio 1:1 with boost.

 

[MoMo52]

Well i do know that im using more gas than it should be.. i get about 18mpg. I know its not running rich, plugs get white. How do i test my fuel pressure regulator? I took the rail off today to use a buddies spare 1g rail, but it turned out one of those injectors was messed up. Didnt even notice it until i pulled mine out. Fun huh? and putting that bolt back into the bottom of the return line was a slut.

Can a clogged fuel filter cause this? I tried to get that thing off today and wowww.. I had to use a breaker bar to get the one on the top off.. and the bottom one made me wanna pull my hair out of my head. Twisted the fuel line a lil bit. Got so frustrated and gave up on it.

 

[embi24]

i read that your fuel filter needing replacement can cause powerloss, it should b replaced once a year in an average commuter vehicle.. any little clogging of the filter can cause your car to not respond like you want it to..

 

[pj91gsx]

You probably have a boost leak. Do a boost leak test.