Quote from Deleted user on May 31, 2019, 9:03 pm

Quote from ratsnotmice on May 31, 2019, 9:01 pm

Quote from TTA Perf on May 31, 2019, 12:11 am

The log looks great to me.

When I look at an idle log, the data I pay attention to are:

Target AFR

Actual AFR

Trim %

Trim Learn

IAC counts

TPS

I always compare Target AFR to Actual and see how close they are.  If they are close, I look at the Trim % compared to Trim Learn.  Trim % is short term adjustments the computer is making to the fuel to achieve target AFR right away.  Learn is stored data the computer uses the next time the engine is at that parameter.  Negative number means it is pulling fuel.  Positive it is adding.  The system will add up to 50% and remove up to -34%.  If your Trim % or Learn are close to those numbers, your tune is off and the computer is maxed out trying to compensate.  The IAC in the 5-15 range helps steady the idle.

Next step is to log while driving.

Sorry to go a little side ways on this thread.

Would it be correct to refer to Trim% as short term fuel trim (STFT)

an Trim Leard as long term fuel trim?(LTFT)

 

Also what LTFT range are we calling acceptable?(I think the answer is low as possible.)

You are correct.  Most installs will be good with the 4 cam selections, ve tables, that are programmed.  There is a way to modify the tables, but only recommend for guys who have a clue.....

Quote from ratsnotmice on May 31, 2019, 9:15 pm

Thanks Austin for the quick reply. Just had my first customer with a Fitech and was pleasantly surprised with it. Check my new post in this part of the Forum.

Quote from Crankyolman on May 31, 2019, 9:20 pm

Quote from TTA Perf on May 31, 2019, 12:11 am

The log looks great to me.

When I look at an idle log, the data I pay attention to are:

Target AFR

Actual AFR

Trim %

Trim Learn

IAC counts

TPS

I always compare Target AFR to Actual and see how close they are.  If they are close, I look at the Trim % compared to Trim Learn.  Trim % is short term adjustments the computer is making to the fuel to achieve target AFR right away.  Learn is stored data the computer uses the next time the engine is at that parameter.  Negative number means it is pulling fuel.  Positive it is adding.  The system will add up to 50% and remove up to -34%.  If your Trim % or Learn are close to those numbers, your tune is off and the computer is maxed out trying to compensate.  The IAC in the 5-15 range helps steady the idle.

Next step is to log while driving.

Thank you, I will do a log while driving this weekend. I do have a question about that. My normal drive is to and from work at 35-40 MPH with several stop lights along my 6 mile drive. Would it be best to log along my normal driving route or take it for a drive on the highway? Of course either way would be after a full warmup and from a stop up to speed and back to stopped.

Quote from TTA Perf on May 31, 2019, 11:31 pm

Quote from Crankyolman on May 31, 2019, 9:20 pm

Thank you, I will do a log while driving this weekend. I do have a question about that. My normal drive is to and from work at 35-40 MPH with several stop lights along my 6 mile drive. Would it be best to log along my normal driving route or take it for a drive on the highway? Of course either way would be after a full warmup and from a stop up to speed and back to stopped.

Start small and just log the drive to work.  You don't have to log the entire drive.  Depending on how long of a drive it is, you can log maybe a few minutes so you don't create a really big file.  After looking at the daily drive, we can look at a highway and Wide Open Throttle (WOT).

Quote from Crankyolman on June 1, 2019, 8:03 pm

Thank you ATT Perf,

Here is today's log.

https://1drv.ms/x/s!AtllmUWFvoeUgisowM08fzhrIWuL?e=Gh3nGe

If it matters the altitude was from about 20ft to 200ft above sea level. The first few seconds were stop and go traffic, followed by 1 mile at 30ish MPH with a stop in the middle, then a stop and another mile at 40mph before dropping down to 25 MPH for a short distance. RPM was between 700 ans 2,000.

Quote from TTA Perf on June 2, 2019, 11:33 pm

Looks pretty good to me.

It is odd that your Fuel Learn is fixed at 29.7  Not sure why that is, but I wouldn't be concerned because it is holding target AFR pretty well.

I did see a few instances that had a lean spike when you first opened the throttle but it was only in the beginning.

How does the car feel?  Any hesitations or problems with driveability?

Quote from Crankyolman on June 3, 2019, 4:00 pm

Thank you ATT Perf,

My truck runs real well with no issues at all, in fact I'm still getting used to not having a hesitation when I step on the gas and the touchiness of the throttle. With the carb there was always a little hesitation, especially when cold but this system doesn't do that, step on the gas and it just goes. The only thing I need to figure out is cold starting. It takes a little more time for it to fire up than it did with a carb but I think I have a grasp on what to do there and am slowly working that out.

Quote from Deleted user on June 4, 2019, 8:43 am

Keep adding fuel to cranking.  It surprising how much.  My 350 is very similar to Fitechs build used to make the default file.  I should need to add anything.  My low temp crank is at 25 and my other two are at 40.

Quote from Crankyolman on June 4, 2019, 9:51 am

Thank you Austin,

I've been slowly adjusting cranking settings. Warm it starts fine but cold cranking takes a bit longer, the biggest problem is I only get one chance a day to see if the changes do anything. With the carb my morning procedure was to give it half a pump and it would start instantly. Ideally I could eventually get this setup to that same place.