I'm currently tuning in SD mode and got the car to idle and it feels good WOT. Part thottle on the other hand is driving me nuts. Under light throttle the car sputters..it almost feels like a lean miss. Anything more than 1/4 throttle and it acts fine. How do I fix this problem?

My LTrims are +10 - +16 part throttle and I can't seem to lower them. I don't think its a mechanical problem, but more of a tuning issue. There are no vaccum leaks and I messed with the VE table and at one point fixed the low end problem then it started to sputter at 1/2 throttle. I just can't win...

Any insight on this would be great.

 

could be bad o2s, ive had the same problem before

 

Do you have a log I could look at?

stlvortac@aol.com

 

Also check your MAF sensor. If it is descreened and you use a K&N (or any oiled filter for that matter) you could have over-oiled and dirtied it. From what I have recently learned, at low RPM it's much more sensitive.

 

yeah a maf thats bad or dirty can cause misfire, my friends 98 did that

 

He said he's tuning sd so the maf isn't causing his problems. So you changed the ve table and it didn't change your trims? What size of a cam do you have?

 

yeah i forgot about that lol guess thats why i never mentioned it in my first post. you have a 2002? so only the primary ve table right? maybethe maf is not failing itself out cause if you change the ve with no changes in the trims it would make sense if the maf was still reporting numbers

 

If he disabled the maf it shouldn't come into play at all. Make sure the map appears to be working, o2's swinging ect. Check out the injector pulse width when its sputtering, is it above or below 10ms or really low single digits, that should give you a rough idea if its a rich or lean condition causing the problem.

 

Just because he failed the maf doesnt mean he is in SD mode. I have seen a few cars not fall over after setting the fail to 0. Got tired of waiting and unplugged it....

 

how do you know if you are in SD? my maf is off the car so i have no questions about it for my car but i just didnt know if there was a way to tell

 

for me it never threw P0101 IIRC

 

i only have a p0102 code and nothing else on mine

 

plus when i plugged it up and unplugged it the afr cahged accordingly and i was dyn cyl air and the maf reading still matched even though the ve table was different and was reading different for the same cells at idle

 

I don't run a MAF at all. It's removed and set to fail. I got tired of messing with LTrims and all that junk after 2 straight days of wasting my time.

Running the car in open loop now, no more sputtering problems

 

good to hear, my maf is gone and i like it that way

 

What injectors are in the car?

 

whose car?

 

im have the same problem on my lq4 with the t70....and they are lean spikes accoriding to my wide band. i also some times get rich spikes when talking out.any suggestions?
have 60lbs injectors and stock everything with maf