Help With My Idle, Not Sure if Mechanical or Tune?

[Supercharged111]

A little background: back in March I swapped my stock cam (190/196 .414/.428 111LSA 106ICL) for a ramjet cam (196/206 .460/.480 with 1.6s 109LSA 106.5ICL) along with some 1.6:1 Comp roller rockers. Since then, on a cold start, the motor sits there and stumbles most days until warm. One little poke of the gas and everything is back to normal, nice and responsive, but the idle is bad enough to affect TCC operation. The exhaust also stinks noticeably more which surprised me for such a small cam, but it's supposed to have more duration at .050" and less at .006". I did end up cleaning my lifters, they were all badly gunked up and stuck in their spots. The plungers wouldn't return to the top of their travel so I had to disassemble and clean them to free them up. I then ran the engine to get it warm and changed the oil and filter and refilled with dino oil and a bottle of Marvel Mystery oil to ensure the lifters were good to go. This fixed my intermittent cold start lifter tick that the truck had had for years. Since this cam isn't much bigger than stock and my LTFTs were within 2% so I never bothered with the fuel, though I will because I still need to from the initial 411 swap (I believe the MAF table is off). With all that said I'm not sure where to begin. I've sprayed for vacuum leaks and didn't find any. I figure the data can point me in the right direction but I'm not sure what all I need to capture or what it's going to mean.

[Supercharged111]

Took a stab and logged a bunch of idle parameters. . . and the truck fired and idled beautifully. That said, there is a little spark fluctuation after the truck fires.

Idle Log 1.efi

Not sure if there's anything to be had here. It idles with 13-16 AC off and around 20 with AC on. Thinking I can probably bump timing around 5 degrees but doubting that's the solution to my problem that didn't show this time. Yesterday it fired and stalled (after sitting 3 weeks and then the battery died) and I had to keep my foot in it for 30 seconds or so before it would barely idle at 400 RPM. Seemed to run fine otherwise.

[joecar]

Connect a vacuum gauge and study it to see it shows any ticks or sweeps.

[Supercharged111]

Those indicate leaking valves, right? I'll dig one out tomorrow and capture data and shoot video. Chances are the damn thing will run perfect again though now that I have time to deal with it.

[Supercharged111]

Finally rigged up a tee to do this. There was only 1 vacuum line on the whole truck! Anyway the gauge was perfectly steady, only fluctuating as the engine initially hunted for idle and then stayed put when the engine settled down.

[Supercharged111]

I've gotten nowhere on this and now that the weather is beginning to cool off, it's going to do it more. I took another short log, of course it only ran rough for the first few seconds. This time though I tried to capture misfires, not sure if GM.MFCSTAT was the way to go there or not? It was all over the place initially as was the spark, desipte the fact that MAP and MAF look smooth and consstant. After the idle smoothed out I took it for a drive to see if the TCC would lock and initially, no. Should have logged trans temp too to be certain the misfire was the cause and not the temperature. It seemed warm enough outside for it to lock right away.

Idle Log 2.efi



And here's a log with the individual cylinders, though the truck was already warm and acting OK. Still got some rogue misfire counts though.

[joecar]

Log the pid GM.MFTOTAL instead of GM.MFCSTAT.

From Log 3:
Looks like #5 logged 20 misfire events over 1.5 minutes... if this did not cause the MIL to flash then it may not be a problem given that ECT had not yet reached warm up temp (i.e. not yet closed loop).

[Supercharged111]

No flashing of the MIL, hell the TCC locked right up too. I am logging the TSTATEs that'll tell me when it doesn't lock, if it's due to trans temp or misfires. Didn't have time to grab the laptop on the way to work this morning, hoping to do it tomorrow on my way in and hoping to capture some good data too. I've added GM.MFTOTAL to the lineup, is MFCSTAT of any use at all?

[joecar]

MFCSTAT is supposed to indicate how far into the misfire determining cycle it has gone, I don't know that it is useful (...or I don't know how to use it yet).

[joecar]

If the MIL is not flashing and the TCC stays locked, then the PCM does not think that the misfire counts are significant...

from what I have seen, 20 counts in a minute or two is quite low, especially since it clears up as the engine heats up and runs more.