Need a little 6E tuning help - Third Generation F-Body Message Boards

dan0617 · 11-06-2009, 08:03 AM

I am running full open loop, '165 ECM. Major mods to a HSR 383. Tune is really good when car is warm and has been shut off and restarted. WOT AFR's hang right around 12.2 to 12.7. Part throttle AFR's range from 13.8 to 15.2. All is well. But....

When I first start the car and warm it up, or when I restart it after it has sat for an hour or so, the AFR's stay about 2 full points too rich as seen on the wideband. Even if I let it run and drive it for an hour, the AFR's will stay way rich. It isn't a false reading, it will pop out the exhaust at WOT and plugs are BLACK if I drive it this way for quite a while. It is way rich during part throttle and WOT. So I pull over, shut car off, restart it, and the AFR's are then perfect. And they will stay fine no matter how long I drive or how many times I shut off and restart the car. Popping out exhaust is gone, wideband reads good, plug readings look good. Unless it sits long enough to cool down, then it will be rich again until I shut it off and restart it.

I've tried alot of things, different AFPR, relocated MAT to air intake tract, messed with a few things in the tune, etc.

What could be causing this? It's almost like there is a setting in the tune that tells it to keep it rich after a cold or cool start and don't let it lean out, then it resets on a hot restart. I haven't messed with any of the CCP settings in the tune, could that be causing this?

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Duts87ss · 11-09-2009, 09:50 PM

Have you messed with cranking and startup fueling? Startup Enrich Decay Delay vs Coolant looks like it might be a place to start.