MAFT setup and tune ?s about fuel trims

[danyz250f]

I installed my MAFT about a week ag and have been desperatly trying to get the fuel trims to 100%. This has been almost impossible.

I have a Gm sensor set up in the blow through, all the dip switches on the box are off, AUX is set at 0, Base at 2, (this is set for stock injectors correct me if I am wrong). Idle is on click 10%, mid is on -15%, WOT is on -30%. I cant remember what letter mid and wot are on but each click is -5% (correct me if I am wrong). I can some times get my low fuel trim to around 100% but only when using my afc as well. The other trims vary a little but usually always settle at 81.2%.

I am half way through my second tank of gas now, and every thing I seem to do to the mid and wot knobs doesnt seem to do anything to the fuel trims.

Also on the SAFC II what ecactly is the lo and hi throttle, and what is it used for.

Any suggestions would be of great help. To get these trims under controll around 100%. Also when do I switch the dip switches into rpm mode.

 

[DSMcamaro]

I'm kind of in the same boat except I'm lucky enough to have my fuel trims close too 100% from the start. right now I have my Idle at 6 (30%) MID F (-5%) and WOT C (-20%). My Low fuel trim usually stays lean between 115-130 and my MID and WOT are just a little lean 100-105 just like they were when I had the MID and WOT knobs at zero.

 

[danyz250f]

Your still having the same problem. I thought about PM ing you and asking if you have yours fixed.

Also at part throttle some times I get 43 counts of knock. I am assuming this is fantom knock and I was wondering if this is bad.

 

[DSMcamaro]

Well i'm not hitting fuel cut anymore.(i'm sure you've probably seen my thread about it in this same sub forum) I still want to do a boost leak test when I get time. If your knock just jumps to 43 at partial throttle its probably just phantom knock. I'm getting 1-6 counts of knock at WOT seldomly but i'm not to worried about that.

 

[danyz250f]

One question for you, are all your dip switches off?

 

[DSMcamaro]

One question for you, are all your dip switches off?

Yes. unless you have a 3.5" GM maf, It should work for you aswell.

 

[alex99gst]

Need to get that boost leak test done already.

 

[danyz250f]

Good idea another leak test. It is a good thing I keep my tester in my car at all times. Leaks before the maf should not matter so much. Am I wrong?

 

[alex99gst]

I do not completely understand the theory behind it of why it does make a difference. I used to think the same thing until I started hitting fuel cut at around 4.5k and after I fixed a ripped coupler before the MAFT everything was fine.

 

[tstkl]

the only change it could make is running your turbo hella hard and out of its efficentcy range and thusly bumping up the intake temps increadibly, but it is not likely that a boost leak before the maf would do anything.

honestly, I've driven my car when I didn't have a front bumper, OR a fmic on it. aka it was just an open uicp. that caused fuel cut like a mo fo!!!!!!!!!!!!

wait, no it didn't, because its a leak BEFORE the maf. it just makes the turbo CRAZY loud.

 

[DSMcamaro]

honestly, I've driven my car when I didn't have a front bumper, OR a fmic on it. aka it was just an open uicp. that caused fuel cut like a mo fo!!!!!!!!!!!!

wait, no it didn't, because its a leak BEFORE the maf. it just makes the turbo CRAZY loud.

Sounds like you were having too much fun.

 

[danyz250f]

Well none of the fuel cut crap, just the pulled timing from stupid phantom knock. So boost hits like a brick wall in 1st gear. Like 43 counts then more boost, knock goes away, bam we'er spoolin.

I am doing a leak test tonight, and I will post the results.

Does anybody know just off the top of their head what size the O ring is in the idle screw, because that leaks a little.

 

[ltvarney]

Does anybody know just off the top of their head what size the O ring is in the idle screw, because that leaks a little.

Not sure on the size, but Slowboy gives the dealer part numbers for their kit.

http://www.slowboyracing.com/more.php?id=3754&