Idle dips M6 WS6

[kyotey1693]

Occasionally, when coming to a stop I get some pretty deep idle dips, sometimes below 400 rpm. So far, the car manages to recover each time but in the past it hasn't. Some of it was due to other tuning issues that I hadn't quite sorted out yet. However, at this point, the tune is mostly all sorted. So, I'm just focusing on those annoying little driveability issues.

I think what I'm seeing is being caused by DFCO. When cruising to a stop the fuel cuts and the timing drops to .5. The dip in idle occurs slightly after this, and I assume the drop in MAP value is what eventually kicks off the DFCO and it starts trying to correct the low RPM. Am I on the right track? Should I try disabling DFCO sooner? What do you guys suggest?

Also, for what it's worth, I've fought Throttle Cracker and Throttle Follower issues extensively in the past. After learning that there are tables we don't have access to in order to fully control those issues, I have bypassed the clutch inhibit switch (not the startup safety switch) so that the PCM always thinks the clutch is out/engaged. I'm mentioning this to say that I don't believe the idle dips are due to a TC issue because it never sees a change in clutch position. Hope that makes sense.

The car is a 99 WS6, 799 heads, LS6 intake, 92mm TB, stage 2 NA cam, headers, exhaust, etc.

Here's a log showing the dips and the most recent tune.

FT7.3.2.hpt
Idle dip @ 5.01 and 7.32.hpl

[kyotey1693]

In case anyone out there is having a similar issue, this one seems to be much better. I raised the Spark Advance Table A and B in the DFCO section which basically says how low the timing can go during DFCO and my idle doesn't dip nearly as much when coming to a stop with the clutch in or car in neutral.

FT7.3.6 Less Timing due to KR, Less TC Airflow.hpt

[Aggie3rdGen]

Kyotey, thanks for posting. I'm running a 6.0L with gen 3 ECU and similar mods with rolling idle issues also. My DFCO is completely disabled by my tuner, but if spark was your untimate remedy maybe I'll look to add spark in somewhere else.