View Full Version : trims question

06-01-2004, 07:47 PM
Ok, let me get this right
There are low, mid and high fuel trims.
You adjust the injector size so that your mid fuel trims are close to %100.

As a result my low trim becomes rich, no problem there is an idle knob on the MAFT.
My high trim is rich too, how do I correct that?
The MID and WOT knobs on the MAFT have nothing to do with that, right?
The RPM mode is for WOT only as well?
It looks like there is no way to adjust your high trims, unless you change the injector size, but than it changes your mid trims and there is no way to adjust mid trims other than changing the injector size?

Is the only solution an SAFC?

06-01-2004, 07:54 PM
what version MAFT?

What are your trims now.


06-01-2004, 08:33 PM
what version MAFT?

What are your trims now.

BobIt's v 2.0
My mid trims are around %115, my high are %98, and low around %100.
I am still running 450's and to bring mid trims down I had to set the injector size to the lowest 430's and the mid trims are still well above %100
The reason I am asking this is that I ordered 660's which will let me adjust the mid by choosing small enough injector size, but I am afraid that this will cause my high trim to go way low.

06-01-2004, 10:10 PM
I dont think your mid trim is that bad. Since you High and Low are right where they "should" be, I wouldnt worry too much about it.

I dont even look at the mid trim, ever. Its gonna go up and down with the weather and what not. The trims are really not that big of deal if they are as close as you have them now. Most say tune for 90-110, your only 5 off with the mid. Not a big deal if you ask me. :)

I too am still running the 450's and have the base knob set at 2. This brings my High trim about 96 and my low around 105. I couldnt tell you what my mid is.

06-02-2004, 11:26 AM
I know when my low trims go above %110, it starts to idle very rough.
And right now I am plauged by a lot of mid knock while crusing.
If I roll onto throttle at low rpms my knock count goes right up to 43 and timing gets pulled all the way.
I get no knock at WOT.

06-02-2004, 02:07 PM
post a log file, i'd like to see what the O2 trim is doing during the transition.


06-03-2004, 11:47 AM
This is my drive home from work yesterday.
As you can see my mid trims went back up to %120
I noticed that as most of the time as soon as I hit around 3.5K RPM the knock dissapears. Is that when the ECU makes a trasition from mid trim to high?