Dieseling

[Webbs]

I am working on a 2008 Z06 with a cam, and boltons.
When I turn the car off it has a slight run on or dieseling. Other than that the car runs great, idles great. What could cause this? Something in the tune or something mech?

[EC_Tune]

Never heard of it and I've done 08 Z06's with cams.

[Webbs]

What would be my best way to log the condition? The only odd thing I can see it that the ect opens from 18% to 26% as the rom drops during engine stopping.

[EC_Tune]

Use one of the configs & histograms from the Configs & Histograms sticky in this forum.

[lafrad]

On an EFI vehicle... there shouldn't be any fuel for it to continue running: the injectors are shut down.

I would look at something weird with your injectors getting stuck "open" and letting the remaining fuel pressure in your system continue to inject fuel. Otherwise... with no fuel.. it should not run.

[BBA]

I'd have to say leaky injector or too rich on idle with fuel puddling in the intake due to reversion, meaning idle AFR and timing was not tuned properly.

[Bluecat]

I've seen that before on a 07 vette with a cam. Not so much like it was dieseling, but more like run on. You turn it off and it would take like 3 or 4 seconds to die down from idle to 0 rpm. I always though it had to do with the push button start setup. I also tuned a 04 Hummer that did somthing similar. But instead of a gradually slowing of rpm down to zero, it just idled at full idle rpm for 3 or 4 seconds after key off, and then shut off. I think it ended up having to do with how they had a tranny cooler fan wired up.

I also had a turbo car that had a manual fan / water pump switch wired up wrong that was cause stupid problems on shutdown from back powering acting like a generator.

[bigbrian442]

I've seen that before on a 07 vette with a cam. Not so much like it was dieseling, but more like run on. You turn it off and it would take like 3 or 4 seconds to die down from idle to 0 rpm. I always though it had to do with the push button start setup. I also tuned a 04 Hummer that did somthing similar. But instead of a gradually slowing of rpm down to zero, it just idled at full idle rpm for 3 or 4 seconds after key off, and then shut off. I think it ended up having to do with how they had a tranny cooler fan wired up.

I also had a turbo car that had a manual fan / water pump switch wired up wrong that was cause stupid problems on shutdown from back powering acting like a generator.

MSD boxes are great for causing this.