'07 Z06 diesels on when shutting off....

[RMS-Man]

When you toggle the pushbutton down to turn off the engine it sputters for a few seconds before it shuts off. Like an old carb car might do when it was really hot outside.
Has anyone seen this or know what to change to fix it?

'07 Z06
Lethal Z cam, LG Pro's, VaraRam, HP Tuning.

Current Tune.
Attachment 13666

Thanks,
Joshua

[Ben Diss]

I had that after I had my heads and cam installed until I properly set my VE table using BlueCat's program.

[Bluecat]

I've also seen that before on big cam cars with the push button start. I just figured thats the way they are. I always imagined the ETC just closing the throttle to kill the engine instead of killing the coils and injectors.

I will say the one that did it the worst was the first one I tuned before I had my program lined out. It would take over 5 seconds to completely shut off. I had it tuned MAF with forcing hispeed mode, so maybe Ben Diss is on to somthing there. Yet another reason not to try and aviod tuning your SD.

[RMS-Man]

I argree with both of you guys and I was disappointed with the idle to 2000 rpm fueling using just the MAF. I need to read up on how to use your program, because I always prefered to have a spot-on ve and then a nice smooth maf to go with it. Seems like all cars I've tuned that way drive the best. Thanks for the help guys.

[Redline MS]

Not sure on the specs on that cam but the what is most likely happening is fuel is still running into the exhaust port after the ignition is terminated. You are correct that this is a VE issue as the PCM does not know that the airflow modeling has changed. This is caused by the overlap in the cam.

The "proper way" is to get the VE coefficients in line so the PCM can control fuel properly. I have in the past been able to fix some of this by lowering the minimum pulse width value from the 4.00 to 2.00. There where also a few other values I changed and it worked well even though it is a work around.

Its all about proper reporting!

Howard