Help with relentless idle surge Twin Turbo 05 Silverado.. Experts HELP!!

[SiriusC1024]

As suggested prior, properly fail the MAF to force SD and put in the correct injector data.

Here's the Deka 80 data.
https://forum.hptuners.com/showthrea...l=1#post745020

Re-tune VE. No use trying to correct all that error with idle adjustments. Your tune is way off because you didn't have it setup right. Seriously.

[JLawson240]

I have already squared away the correct SD settings if you read, and again for what it's worth the changes made no difference whatsoever in the idle condition. Thank you very much for the injector data. The owner is going to make a few changes to the setup very soon so I'll be retuning the truck on a hopefully new PCM and 3 bar OS anyway.

[SiriusC1024]

That's because setting SD on its own won't fix it. The tune is not squared away with incorrect injector data. I can look at the VE and see the shape and values are wrong. You have to understand that having the wrong Offset and SPA is what you're fighting at idle. You pointed out that the O2 sensors are oscillating. Yeah, but look at what STFT is doing. It's not consistent because error in fueling (VE) is being corrected with error in injector data.

Also, the spark over/underspeed corrections are too large and causing such a big idle swing that it's invoking the adaptive idle PI routine. A good tune will be able to hold idle with just spark.

You 100% have the wrong injector data. That means the rest is wrong. Just try it the right way.

[blindsquirrel]

The majority of the calculations the PCM has to do are all to answer one not-so-simple question - "right now, under all these different conditions, how long does the next injector pulse need to be?" And if the baseline numbers for how the injectors behave at very small pulsewidths are wrong, it consistently comes up with the wrong answer. And the smaller the IPW the more impact errors in the data will have.

[JLawson240]

Sirius I sincerely appreciate the information and truthfully plan to re-do the entire tune using correct data when he makes the next round of mechanical changes in the near future. In the meantime, he's not too worried about it.. the truck has been driven this way for 2 years and is a stock 282k 5.3 that he could care less about... lol

[edcmat-l1]

Strange thread.

OP: "HELP with relentless idle surge Experts HELP!!!!"

EXPERTS: "Try this this n this. OH yeah, here's a cal file to try"

OP: "Already tried all that, nothing worked."

OP: "Nevermind. Customer doesn't really care. Car runs great, mostly"

[JLawson240]

Strange response..

OP- I already tried most of what you guys suggested and nothing made any difference.

EXPERTS- Please keep trying.

OP- I will trust me, but for now the owner has the truck back and in the next week will be doing more mods so I'll retune it correctly then.. In the meantime it's not too big a deal because he's been living with it for 2 years and will be glad to live with it for another week or 2.

Not sure how you interpreted what I wrote my friend but I've been more than open to everything you guys have suggested... Dunno's

He's planning on locating another PCM and doing a 3 Bar OS anyway.