hard start high idle and P0606 LS7

[Tool Guy]

Hi. I am having a little trouble with a 2007 Zo6. The car has a cam, ported heads, and NW 102. The car runs great, but I will get a P0606 (blinking) for a few sec during WOT and P0507. Additionally, most times, the car will need the throttle lightly touched to start while hot, and will idle around 1500-1700 after driving. I smoke tested the engine and don't have any visible air leaks. I tuned the VVE and MAF steady state on a load bearing dyno, and my fuel trims are very close. Did I miss something? The current cam and head package is a revision to a previous setup. I tuned the original setup years ago and never had any problems.

I have attached a tune file and log file at idle.

Thanks

[joecar]

Actual idle is exceeding the desired idle tables, so maybe that's what is causing the DTC's to trip...

so have to find out why it is exceeding the tables.

Trims do not seem to indicate exhaust air leaks.

[Tool Guy]

Thanks for looking at it. In your opinion, the tune isn't the problem? The procedure for the p0507 says to look for an air leak in the intake. I did a smoke test and didn't see anything. I also tried spraying with brake cleaner while running. Assuming the intake doesn't leak, I would guess the issue could be TB or related electronics.

[Hib Halverson]

DTC P0507 is, of course, the high idle code.

Obviously, vacuum leaks can cause it. But also any air getting into the engine which is not metered by the MAF can do it. Finally, a bad or incorrect PCV valve can do it.

You smoke-checked the intake but that only verifies there's no leaks in visible/accessible areas. Any chance the manifold is cracked on the bottom?

Also, not only could an incorrect PCV valve do it but if the PCV tubes/hoses are leaking or improperly connected that might do it.

One thing that puzzles me is that your hot idle speed, 1500-1700-rpm, is not just a little high, it's a lot high. There would have to be a pretty good sized leak for that to happen.

DTC P0606 is an odd one, for sure. That's an ECM fault which sets if the system voltage goes over 5.23v. It also may set if the ECM is programmed improperly.

I'm kinda thinking you might try a reflash. Also, you might ask Joe if a full reflash rather than just a cal flash might be a good choice.

[joecar]

Hib has some good points.

I would try a full flash, but take the usual precautions (make sure: car battery is fully charged, laptop battery fully charged, other modules prevented from talking on CAN bus).