Timing drops to Zero on decel?
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Anybody ever observed this before? I was riding with my buddy last night and we noticed in fourth gear going down a hill, if he lets off the gas completely the timing drops to 5-0 degrees advance, and quite a few times it just sat at zero. I checked out the fuel trim cell that it did this in and it was FTC 21. Anybody else ever notice this? What would cause this and is it bad? I know he does have lazy o2 sensors. I'd imagine he might be running open loop all the time because they dont move around much.
#2
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I think that is normal. It is probably the car going inot DFCO mode (Deceleration Fuel Cutoff) it is just a mode the car goes into to save gas and comply with EPA emission regulations.