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145702

lol

Post the tune file and data log. Can't do anything without both. Other than just guess at stuff.

I didn't see anywhere in the "pull example" log where it looked like it went into REP. It is a cable throttle body engine so it shouldn't be able to go into limp mode. In the data log there's a pull...

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."
...

Never seen any of that. And I'd have to question all of it unless I diagnosed it myself. No offense. I know you're a smart guy. I just don't take anyone's word for anything when it comes to...

What is wrong with the "bad" PCM?

I can't remember the last GEN4 I had that needed a PCM replacement to fix something. I can think of a small handful of GEN3s I've replaced to fix oddball shit. But even on those it's hard to know if...

30 years now as a certified master tech. About 6 years in a GM store in the 90s. I was an AC Delco shop for quite a while so benefitted from the same training for several years after.

I own an MDI2. I've owned a TECH1 way back when, then a TECH2, skipped the MDI and went right to the MDI2.

I'm a former GM tech. I use SPS weekly.

What's "bad" about the PCM? What failed in...

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

145605

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,...

Yeah pretty much same here. I translate "Bad PCM" to "I don't know what I'm doing".

No offense OP, it's just incredibly rare for GEN4 PCMs to go "bad". Don't know when the last time I've seen one....

^^^ First you say it's been unsuccessful.



But then you say you were able to flash the VIN, etc.

So, either you were able to successfully flash it with SPS or you weren't. The fact that it...

LOL where's the smooch emoji? LOL :hi:

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

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

A wideband doesn't mean anything in a non running engine.

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...

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...

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...

Does it need MORE fuel or LESS? Have you tried WOT clear flood mode? Are we just assuming it needs MORE fuel? Have you tried just cracking the throttle?

Do you have data logs of various starts...

Congrats on the find. Right at the buzzer. 5 pm quittin time LOL

If there was enough valve train damage to cause a noticeable miss I'd think there would be some noise involved.

If there was enough valve train damage to cause a noticeable miss, it should show...

If the VE in that revision has been dialed in up top with your wideband, you're losing fuel pressure. The VE should not be anywhere near that high.

The high octane spark table still has bad dips...

Put it back in closed loop and use the trims to dial it in. Forget about your wideband. Straighten out the spark tables. Get rid of the cliff in the VE table at 6400 RPM.