Help please.

Hi everyone, I'm stumped I have no tuning experience, And i have been watching the courses now for about 5 weeks, my problem is I am trying to sift back through all the information and i am getting information overload, trying to find how to change my commanded afr, in a older red and blue connector pcm (411), when i manually enter a new commanded value of 14.68 from 14.42 my wide band shows the engine starts running richer at about 13.1 or there about can someone help me understand what im doing wrong or where the information i need is located and in which module thank you it would be really appreciated James Workman

Anybody?

Hi James, can you give us a little more info? What engine is the PCM controlling? How are you making tuning changes? Have you scanned the PCM to confirm that your commanded AFR is in fact changing to your new target?

Hi Andre, I have a ls2 iron block 6.0 bored .030 camshaft is 218/224 .553/.553 113+3, it has ls 799 cylinder heads supposed to have a performance valve job, with dual valve springs, rated to .660 lift. The pcm has a different os because i also used a 4l80e transmission and could not find a patch that would work with the stock os. I ultimetly ended up getting a mail order tune from a tuner than I did some email tuning back and forth to where i am. recently it failed hc emissions by 120ppm

The injector information that was in the mail order tune was incorrect so i used the compare function and corrected it. The commanded afr is 14.42. its a p01 controller, i tried to disablethe maf to start on the ve tune but when i was done the commanded went to 14.60 and not what i had input for the commanded of 14.68, also how do you suggest hitting enogh blocks in an automatic vehicle, just riding the brakes. i also got confused dealing with lambda instead of afr,but I do understand now that lambda is a reference between commanded and stoich, any suggestions any info or direction would be Great. thank you

Did I miss information that you requested?

It might help if you post up your calibration. Are you only having problems with the commanded AFR under closed loop conditions or does it not appear to be following your targets under PE too?

GM throw another curve ball into the mix as the PE targets are actually equivalence ratio which is the inverse of lambda (1/lambda). It's important to understand this to get your targets where you actually want them. What injectors are fitted to the engine? What has been done to the intake system?

With an automatic transmission it's not possible to access all of the cells in the table but you can do a pretty thorough job by locking the trans into a gear and using the left foot braking technique. All of this is covered in the worked examples on the HP Tuners platform in the Practical Reflash Tuning course.