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

[JLawson240]

I'm at my wit's end with this thing!! At this point I've tried absolutely everything possible with idle control to alleviate this surge but NOTHING, and I mean NOTHING I've done has resolved it. I've played with the PID controller up and down to absolute exhaustion, I've completely disabled and zeroed out all the airflow adaptives that I think have anything to do with idle control.... nothing helps. In most starting situations the truck idles down and then immediately your can audibly hear the throttle blade going crazy and see it in the datalog as well. Sometimes it will begin it's relentless surge after a quick neutral rev but what upsets it bad and gets it surging every single time is a held rev in neutral or park to any rpm. If you just hold it for a couple of seconds and release the throttle the RPM drop quickly to about 500 rpm, the truck almost dies, and then it goes bananas. Just surging up and down for sometimes a minute straight unless you give it some throttle to settle it. Myself and a couple of other local guys have tweaked this same truck with no luck. We both thought we were dealing with a bad throttle body/IAC/TPS sensor, but that's just not the case. We've swapped 2 new ones on at this point both AC Delco and Dorman and the issue persists.

I did not tune this truck initially but at this point the only thing left in my mind is MAYBE something with the injector data???? In checking the part number the injectors appear to be the Siemens Deka 80s with the red bottom. Having never tuned these personally after a quick search there appears to be tons of conflicting info about accurate data. Anyway, setup is as follows... I sure hope someone can help with this!

-05 Silverado, stock 5.3, very mild unknown boost cam
-Return style fuel system, On3 regular reads 78-80 psi (holy moly), Deka 80lb injectors (part number A2C32624700/K052A01527), tuned @ 15 psi on E85
-Twin 68mm turbo kit
-Stock intake manifold/throttle body
-MAP sensor# 12615136 (I double checked this data and found a 8 KPA offset instead of the 10.33 that this truck was tuned with... any input??

The datalog attached is of a rather smoother idle honesty. This log didn't capture the crazy surge but there's nothing that stands out in the data when it's doing it anyway.

[edcmat-l1]

The datalog attached is of a rather smoother idle honesty. This log didn't capture the crazy surge but there's nothing that stands out in the data when it's doing it anyway.

Oh I beg to differ sir. It is perfectly obvious and I'm surprised it's as smooth as it is in this log. The throttle blade is WAY too active. Without even looking at the tune file the throttle PIDs have to be totally whacked.

throttle.jpg

[edcmat-l1]

I did a compare to a stock file and the PIDs are much closer to stock than I would have thought. If it were in my shop I have the luxury of having stacks of PCMs and unlimited credits so I would start over completely with a different PCM and base file and wouldn't carry over anything from this one.

[JLawson240]

I'm telling you brother I've tried stock PIDs, no PID, every combo of raised/lowered PID I can think of... nothing helps. The owner claims the issue started after he cleaned his original throttle body the truck was tuned on, but since then it's had 2 brand new one's installed and the issue has persisted. He just ordered a pretty aggressive cam for it so I'll be going back over it soon anyway, but if there's a PCM issue or something else going on I don't want to waste my time or his.

You think the injector side of things could even possibly have and impact?? My brain is struggling to see the connection but goodness I'm out of ideas..

[blindsquirrel]

Every cell that got populated in the trims error chart is lean in that log, MAF Fail is = 100hz, P0101-103 are set to No MIL instead of First Error...

So the file needs to be set up by someone who knows what they're doing, then it needs to be tuned, only then should the idle settings get looked at.

[JLawson240]

Woah nelly!!! Yes it's definitely lean but again I didn't set this original file up at all.. it is Speed Density only, and if you notice my profile I'm a novice in the grand scheme of things my friend. But in all my research you gentlemen replying are the real deal in here so PLEASE educate me on how to properly set this up for SD only. In other SD tunes I've seen 0hz or 1 hz or something, so the 100 hz didn't just jump out at me.

[JLawson240]

For what it's worth I changed the MAF fail to 0hz, and the MAF 101,102,103 codes to MIL on first error with the SES box unchecked. No changes at all.

[blindsquirrel]

0hz if the MAF is removed, 1hz if it is just failed temporarily for tuning VE. P0101/P0102/P0103 set to MIL on First Error. Engine > Airflow > Dynamic: Dynamic Airflow: High RPM Disable = something ludicrous, like 8,000.

Injector data is whacked - Deka 80s do not flow 80.0lb-hr at 58psi. So without looking I'm pretty sure the other tables are wrong too.

[bk2life]

does this run and drive or has that not happened?
are they O2s working?

i havent open your files, but im wondering how lean it is, if you give it 15% across the board and then drive it and get some real data to see what its doing not just during idle.

[JLawson240]

Thank you! I had my assumptions about this data as well given the ruckus online about these injectors. The truck runs and drives just fine honestly, O2s function, and the truck pulls hard under boost/full throttle. This idle issue is literally the ONLY issue from a drivability standpoint.

Blindsquirrel.. Any input on where to locate some good injector data. I don't expect anything just given and I'm willing to dig and go down some rabbit holes to find the correct information, just need some idea where to look.

[blindsquirrel]

https://forum.hptuners.com/showthrea...ata-Repository

[edcmat-l1]

It's not injector data. Even if it's wrong it won't cause that violent swing in the throttle blade. Something is going on most likely in the background. Wipe that shit clean. Start with a totally different hardware and software platform.

[JLawson240]

Thats what I meant by my brain struggling to see the injectors as a culprit for this particular issue. By saying wipe it clean and start with new hardware are you talking ECU, harness and all or just the ECU itself? Definitely haven't run into having to swap control units yet in my tenure.

[edcmat-l1]

New/different PCM and completely different calibration file. Don't carry over anything.

[edcmat-l1]

Every cell that got populated in the trims error chart is lean in that log, MAF Fail is = 100hz, P0101-103 are set to No MIL instead of First Error...

So the file needs to be set up by someone who knows what they're doing, then it needs to be tuned, only then should the idle settings get looked at.

Didn't look at that until just now. That could definitely make it do some wonky shit.

[Alvin]

1. The throttle/pedal tables aren't stock. I'd put them back.
2. Are you sure the injector data is correct? It's off by quite a bit from what I use.
3. If the throttle body has a issue like a bad TPS you will see TPS move around as if the throttle body is commanded to do so. So that bouncing TPS value might not be what the computer is asking for. Do you have a spare throttle body to try?

[JLawson240]

Alvin I?ve tried everything you mentioned including 2 new throttle bodies (AC Delco and Dorman). Tables back to stock.. nothing matters at all. As far as the injector data no clue honestly, but again rationally I can?t link the idle condition to that data. I?m with Edcmat at this point.. I think this PCM is fried in some kind of way.

[edcmat-l1]

Alvin I?ve tried everything you mentioned including 2 new throttle bodies (AC Delco and Dorman). Tables back to stock.. nothing matters at all. As far as the injector data no clue honestly, but again rationally I can?t link the idle condition to that data. I?m with Edcmat at this point.. I think this PCM is fried in some kind of way.

I don't think the PCM is fried I think there's probably some stuff in the background causing it. Only way to tell is to start over with a fresh new, different calibration, OS, complete file, preferably an SPS update, in a new box, and go from there.

[edcmat-l1]

Flash this in and post a data log. Let's see what it does.

Crazy idle tune_EH1.hpt

[JLawson240]

I just dropped the truck back off with the owner so I can't flash that exact tune. I noticed you bumped the Proportional up some and I can promise you I tried the same thing and almost every combination of raising/lowering the PID controller. I gotta be honest... I can't even count how many different files I hit this thing with.. it's embarrassing. But I'm obsessive in nature and will persist until a solution is found.

I discussed some options with the owner and I think we're gonna try a new PCM when he gets the chance. Aside from the idle quirk the truck drives great and pulls hard and in the grand scheme of things you really have to TRY to upset the thing to get it surging bad. Under 95% of conditions the truck drives fine.