Fuel Trim Tuning Problem

[Andrew7DG]

Little bit about the car

1990 Eclipse with 1990 ECU
Tuning with a MAFT (thats all I have for right now)
Pocket logging with a Palm

I am new to tuning but something still doesn't seem right

And please correct me if I am wrong about any of the tuning that I have done

I am trying to get the fuel trims to 100%

In the palm there is
Low
Med
High
02

I know you are not supposed to use the 02 for tuning

I have got the Low fuel trim pretty close to 100%
It is the Med and High Fuel trim thats giving me problems.
They seem to be stuck at 81.7% both...

How fuel trims work to my knowledge is that the low fuel trim is when the car is just idling around and then on higer RPM the Med or High take over

So the Fuel trim on low goes back and forth between 95% and 107% give or take not fast like the 02 reading but it moves.

I took the car on the highway and the Low stopped moving which to me means that the med or high took over and so I start playing with the medium switch on the MAFT because that is what the car is running on (dim green light) I was playing with it and I can't get the med or the high to move at all.... the engine changes sound so the MAFT is working but I don't think the computer is correcting. The 02 sensor changes percents but I can't get it to read over 100%.....

Is my ECU Bad? Bad O2 sensor, something wrong with fuel delivery?

 

[surgeon_general]

How long are you waiting for the medium and high fuel trims to change?
When I tuned for my fuel trims I would have drive around for 15 or 20 minutes before they changed. They dont change as fast as the low trim does on idle.

 

[RMeadows]

Those trims take a long time to adjust, easy way around that is to reset the values(disconnect battery or ECU fuse) for a few seconds. That will make it much easier. By those numbers you posted however, the car is running WAY rich, it's basically maxed out on the software(81.2). Lean the car out slowly while keeping an eye on the 02 trim while you drive around. the MAF-T can be tricky but with time you'll figure it out. Most importantly, before doing any of those things, since you ARE running that rich, make sure you do a boost leak test

 

[Andrew7DG]

I was thinking of letting the computer zero out however that won't mean that the rich problem will be fixed. I was taking drives to and from work/ and school which are about 30 min..

I will boost leak test to see if I am loosing air somewhere which I could have lost a cap on the TB or a leak somewhere else.

I was thinking that the Medium and High move just as fast as the low so that is good to know that they take a little longer to change.

I am actually surprised however because I have been getting good fuel milage...

thanks for the replies and I will let people know how this turns out.

PS.. i will be getting a different tuning device soon

 

[Andrew7DG]

Just wanted to update that I did a boost leak test and there are no boostleaks... I am actually dissapointed because that would mean it would be kind of an easy fix.

So now computer is going to get reset to zero and what I might do is play with the base setting, set it a little leaner the before. I will tell results of that next

 

[architechnik]

Along these lines, would a bad narrowband attribute to the ECU making it run rich?