Hello,

I have a yukon that wont run right when a load is placed on the motor. The installer/tuner has been stumped for many months now. We cant seem to figure out what is going on. When the car is park it revs fine to the limiter. But when you drive it, it runs horrible. I personally haven't driven it but the shop says that the tune seems fine. I had them send me a log and the config file to post here to ask for some help. Could someone please take a look at the tune and log and see if there is something wrong with the tune.

They say it revs fine in park, but when you drive it it acts like the computer is taking out timing or something at around 2500 rpms or as soon as boost comes on then it is very hesitant till around 4500 then it starts to take off again.

Tuner said that they have exhausted everything to try to get my truck running but it has been 6 months now and I have no truck. Said they checked it with wideband and cant find anything wrong with the tune.

Specs on the truck.
rebuilt lq4 block
799 heads
ls6 cam and springs
on 3 turbo kit fmic
Garret gt4094r turbo a/r .95 (I think)
FAST truck intake manifold
Fast fuel rails
Walbro pump
Aeromotive regulator
Injector dynamics ID 750
BBK dbw t body
MAD DOG level 3 4l60e

2000 yukon slt
2WD
Drive by wire
traction control

Truck ran and drove perfect when I dropped it off in October.
Now the fuel guage is at the 6 oclock position, and I noticed the tack wasnt working then it kicked on after about 30 seconds.

I would gladly pay someone for their time if they can solve this issue.
Any other info needed please let me know.

I attached a HP tuner log and config file
Thanks

 

I saw this on Hp Tuners, the person that commented first is right.

They wrongly changed a table so it commands far more fuel than needed and basically kills the motor. They need to change that to fix the biggest issue. He provided a "fixed" tune that they should look at.

 

Thanks for the response. I sent the fix to the tuner. He said it is still doing the same thing.. He is making a new log with the changes in place. And a wideband logged as well. Hopefully we can get it resolved soon.
I should have a new log and config file tomorrow.

Its really wierd to me that he hs having so much trouble, There are always new corvetts and turboed trucks there for tunes. He has only had trouble with mine. Unless he is just uploading someone elses tune to thier cars.. At this point I am wondering..

 

I have the demo software running on my laptop. Could you tell me which table was commanding so much fuel? The only thing I saw was the coolant temp pe table was adding 1.17 additional fuel. Which isnt enough to kill the motor.




Looks to me like when the motor is placed under load it is killing fuel and spark.

Just looking at the data charts. When the tps and map goes up. the spark and injector dudy cycle is going to zero..

I am hoping to get a new log with wideband data tomorrow.

 

Lets do some math here shall we.

So your tuner wants a EQ ratio of 1.172 right, so thats roughly 12.52 AFR.

But he has the ADD vs Coolant at 1.172 across the board. So now add the two together, thats 2.344 combined commanded EQ ratio.

Now do more math that comes out to 6.26 AFR commanded, all the time.


14.68/1.172 = 12.52
14.68/2.344 = 6.26.

They need to fix that. Just set it to zero, you don't need it to add extra fuel while not in booost. Thats why you have a boost enrichment table set to 1.23 eq ratio, so around 11.9 afr.

 

Yea its way way too rich and its pulling all the timing out.

Not sure about this "tuner". This is a very basic issue.

 

Thanks guys ..

I didnt understand the "adder" part..

I was doing the math wrong
14.7/1.172 = 12.54 / 1.172 = 10.7

I get it now..

Your help is greatly appreciated..

 

No problem.

 

Not quite... 14.7/(1.172+1.172)=6.27

 

Atomic, I think he was saying that was how he was doing the math, and he got 10.7 as the end result which in real life wouldnt be over fueling in many cases.