5.3 2008 Suburban to 6.0

[cfaluck13]

Trying my first time to copy/paste a 6.0 tune to the stock ecm. Copied everything over from a ly6 tune because I was under assumption the new engine was a ly6. Seems to run just fine besides cold start.

It surges at idle on cold starts as the timing starts out pretty low and then jumps up and down into the negatives pretty quickly. Only things not changed over on the tune is the map sensor since the original one from the 5.3 was used, and also the electronic throttle parameters were not changed due to the warnings that it can harm the ecm.
Not sure if its trying to use spark to control the idle since it has the TB from the 6.0?

Weird part is if you turn the truck off and restart it, it idles just fine.


Come to find out this new engine is a l96 and not a ly6, copied over a l96 tune, and the truck would only crank, no start.

Here's the tunes I'm working with, hoping I'm just missing something dumb here. Didn't save the log. Ill have to wait for it to cool down again to get one.

[5FDP]

The 6.0's also have VVT, what did you do about that?

You never enabled the VVT in the tune.

[cfaluck13]

The 6.0's also have VVT, what did you do about that?

You never enabled the VVT in the tune.

The new engine is completely stock so it still has it, but left it disabled in the tune to possibly eliminate any weird issues I thought it might cause.
Think I should copy those over and turn it on?

[cfaluck13]

Here is a log from this mornings cold start. You can see the timing starts out oddly low around 1-2 degrees, then slowly goes negative until it starts jumping back and forth causing the surge.

Then I turn off the engine and restart it and the surging stops.
Timing still seems lower than what is in the low octane table for idle at this point still though.

Any ideas?6.0 suburban idle timing jump.hpl

[cfaluck13]

So Im noticing that on a cold start after about 2 min of run time the ecm is commanding 600rpm idle speed.
But the engine is staying around 700rpm when its surging. I've added in the VVT parameters from the 6.0 tune and it got slightly better but still prevalent.

Could it being pulling the timing out to try to get the idle where it wants? (Since I did not change the throttle body parameters in the tune, due to the warning of causing ecm issues?)


Still very weird that a quick off-on key cycle fixes it every time.