Joe_G

I'm sorry I missed that you have a cam.

Your problem is common. Have your tuner increase your starting airflow table a little bit. He will know what to do. Might take a couple of fine adjustments.

Yes, ECT is the main trigger. It will try to get to closed loop quickly as that is best for emissions. Most common thing to take it out of loop is acceleration past a threshold which you can adjust in your tune.

BK n BLK

Hi
As stated above it will not be a O2 sensor, you say you have proper fuel pressure, If you have a code reader I would unplug MAF and try it, yes a code will be induced but it will fire up on default perimeters, that will eliminate that sensor, I have seen leaking injectors cause this problem, any smoke on the start up like a rich mixture?
I would read data check coolant temp sensor also before fire up.

Joe_G

I missed that it diesels on shut down. Does it have a bit of "cruise control" when you take your foot off the gas?

All three of these things are simple airflow adjustments that you have to do when you tune for a cam. The startup airflow table needs to be increased a bit so it starts easier - don't go too high or it'll flare to high rpm upon startup and that sounds cheesy, the dieseling would likely be caused by a bit too high settings in base running airflow, which can also cause cruise control. You can knock that table down a bit to take care of these, you might have to adjust commanded idle speed to compensate, perhaps not.

Your tuner will know where all these tables are and should be able to get you fixed up pretty easily.

zali0104

Like Joe G, i missed the dieseling on shut down.
You need fuel and an ignition source for dieseling. If there is an injector leak, or multiple injectors leaking that can be the fuel needed for dieseling. On a hot engine you can have an Atkin's cycle situation.
An injector leaking fuel into the intake can explain the extended crank as the flooding is cleared.
Put a fuel gauge on and check pressure drop after shut down. Loss of pressure would indicate a leak.

SlowBusa08

I added a little air flow on the idle air table and it does seem to start and idle a little smoother. I noticed the coolant temp modifier map was a little lean causing the ecm to try and over compensate.

I need to smooth it out a little more but it seems like it did make an improvement.

I do notice the cruise control affect, i'll poke around and see what the base running air flow tables look like.

I'm use to tuning diesel so having to worry about airflow is f'n weird... Diesel just take as much fuel as you tell it, and they figure out the rest.

I appreciate the help guys, keep it coming.

Joe_G

Didn't know you knew how to tune. Take the base running airflow down 5% and see how that does for you. Might have to bump commanded idle speed a little.

If I'd known your mods and you tune, we'd have fixed this in the second post. lol

You coal guys.... lol all you have to worry about is how much oil you can stuff in that thing.

SlowBusa08

Lol absolutely. I tried to keep it clean out of the pipe so large twins we're needed. But essentially you're correct.

I'm using efi live so bare with me I know enough to be dangerous. On the baas air table do I drop the whole map by a few percent or log it and drop specific areas?

Joe_G

Scan it and see where it idles and where you have cruise control and adjust down.

Frankly that table is only used in those areas so you could probably drop the entire thing 5% and have the same effect and save some time.