FAST tuning questions

[foxspy]

Hey guys,

I am having some troubles tuning my truck. During a cruise, I have the wide band set at 14.7:1, and I get my VE tables to close to 0% O2 correction, and it runs good. Then I turn off the truck and next time I start it, it runs crappy again. When I turn the truck off, the laptop says "Com write fail", or something of that nature. What does that mean? Do I need to save the files before I turn the ecu off?

Also, in some areas of the map, the 02 corretion will be at 0% and it still runs real crappy, what do you think the cause of this is? Does the motor just not like running at 14.7:1?

I thought about turning off closed loop and try tuning it that way, but that's a waste of the wide band option, isn't it? What do you guys think?

Any help is appreciated.

 

[T66Typhoon]

Your thinking is a bit flawwed with respect to the A/F ratios... when cruising.. the leanest point in my truck map is 13.5

I know you are thinking 14.7:1 is stoic, but that really means nothing.. if you have the table setup so that your corrections are 0% that just means you have your VE table set up accurately, that is all... so go into your map and try running your A/F's down.. start in the 13.0 range and see how it is there.. if you are trying to run 14.7's.. when you give it the least bit of gas you are having to add a huge amount of fuel with the AE tables so it probably going lean immediately when you are stepping on the gas.

As far as the comm write fail.. you hit it right on the head.. you don't have to save the file before you shut the truck of, talking about during logging here, but you do have to stop your logging before you shut it off. If not, the file will be lost.... hope that helps.. be sure to read a lot here.. there are tons of good posts that will help you with part throttle stumbles etc.

Don't hestitate to ask one of the experts on the board to look at your gct file either... helps if you can send a data log and an idea of your build with it... someone here will take a look for you. There are lot of people here who know these ECU's really well.

It is going to take some time to learn.. but asking questions is a good first step.

 

[Syclone Dude]

Nick is correct try using a richer a/f ratio, some cars (especially modded ones) prefer more fuel for cruise and idle. A good practice is to log off the ecu (F2) when either shutting off the car or closing the software, if you don't sometimes (Not Always) the software will throw in a spike somewhere (could be in the AE or throttle follower or wherever it wants).

hth
BigAl...