DSMLink and LTFTs

[No_Skillz]

I need some help on my LTFTs. These are logs after proper warmup and cruising times. I tried adjusting global settings to 5, but that change has made my LTFT mid go to 9.8%. This is on a stock fuel setup. I'm brand new to Link, any suggestions are appreciated.

 

[Staytuned]

I set my trims using selectedLTFT for idle and cruise speeds (60-70 mph). This will switch back and forth through the trims used at these above engine speeds. What you need to do is follow the DSMlink user guide to set your trims properly. If you have straight forward setup on your car, stock MAF no GM stuff and all your honey combs intact set your global and DT to your injector size. This should be very accurate unless you have air metering problems or your injectors don't flow as much as they are rated for.

 

[No_Skillz]

I went through the DSMLink manual and all it says is to adjust global if my LTFTs are about the same, but non-zero. I did set my global and DT all to 0 for my stock 450s, yet LTFTs are still at 8-12%.

 

[Staytuned]

In your case you are lean so the ECU is adding fuel (8%) to compensate. You have no where to go with the DT or global sliders because you are already at 0. You need to for now tweak the airflow sliders to add fuel and you will come down in trim %.

 

[No_Skillz]

So I need to bring down the airflow sliders a couple of ticks to shoot for 0% trims?

My main problem right now is that the car feels unsmooth when accelerating normally under 3k rpms. It feels smoother after 3k. Also, idle, steady cruise, and WOT operation feels totally fine. Could this problem be caused my my LTFTs being off?

 

[Staytuned]

You need to bump the sliders up in the airflow section. Adding Hz at the 50 slider and 150 slider will change your trims. I would set your 50 to 10% more and your 150 to 8% more and go out and see the difference.

I don't think the trims being off is creating this drivability isssue for you though.

 

[Staytuned]

Here is one of my logs....check my airflow sliders to see how I have tweeked them to compensate for a hacked MAS and other things that change airflow metering.

 

[IgoVroom]

I am having the same problem. My ltft's are about maxed out but I was able to get them down by adjusting the MAS sliders but now my car runs like crap. I have stock intake aside from a k&n and stock injectors. So I don't see why I should have to mess with the MAF settings...But it did seem to help, I had to go about 10% to get it down on the left three sliders. ( 50, 150, 250 )

I should have a wideband o2 by the end of the week, my plan is to tune for around 0 ltft using the maf settings then tune for around 11:1 at wot with the wideband. Then adjust timing advance as much as I can without getting knock. Is this proper procedure? What about low rpm ranges, is it still safe to advance timing in low rpm's?

I tried adjusting fuel down to run at 11:1 according to the dsmlink ecu tuning guide, but it made my car run SLOW and bad….Is this because I didn’t do anything with timing?

Actually I’ll post a log so you can look. I know I have some knock, but the car was slow through the whole log not just where there was knock. Sorry if I hijacked your thread, No_Skillz but I figured you might want to know this stuff too.

Oh and someone told me the problem I am having could be caused by boost leaks or un-metered air. You could test for leaks and see if that's your problem...I couldn't find any myself.

 

[scottsee]

You need to bump the sliders up in the airflow section. Adding Hz at the 50 slider and 150 slider will change your trims. I would set your 50 to 10% more and your 150 to 8% more and go out and see the difference.

I don't think the trims being off is creating this drivability isssue for you though.

I agree... 10% to 50hz & 8% to 150hz to start. I have the same problem with my stock injectors & maf. Keep an eye on your boost gage at 5500rpm when doing WOT pulls. Log and compare with BoostEst. Make changes if necessary using MAF as your HZ guide. I would strongly suggest investing in a 3.3bar map (GM#9373269) and weather pack connection (GM#88987997) from www.gmpartsdirect.com It makes airflow settings sooo much easier

 

[scottsee]

IgoVroom. You need to turn your boost up if you're really only running 15psi. You're peaking airflow at 2.27 g.rev @ boost threshold. Remember as soon as you fall under 2.1 g/rev you move off your top maps. I would seriously recheck for boost leaks. Your lb/min airflow numbers are significantly inflated for 15psi/14b. I see 29lb/min @ 21psi w/h20. From that log, it looks like your front 02 is dead.

 

[IgoVroom]

Thanks again scottsee...I was actually thinking that was my a/f ratio isn't where it's suppose to be, or it's because I had messed with the MAF settings.

Once I get my wideband tomorrow and tipple check for boost leaks using a different air compressor I will try turning up the boost a tad and see if that makes tuning any easier. Right now I turned everything back to stock.

I bought a aem six in one wideband, is there anyway I can install it and get away with not having to buy a stock o2 sensor? I'm kind of broke now.