I had a discussion with a couple guys from work yesterday regarding Fuel injector shut off on decel.

My assumptions were the injectors shut off at closed throttle, relatively quickley when left in gear (manual) rolling up to a stop light, assuming the engine speeds were up, maybe aboue 1500 rpm or so.

A couple guys weren't aware that modern fuel injection had this feature. others claimed there was more criteria that had to be met before shutoff.

Test run on my dd (2000 cavalier), I only got em to shut off once, while engine braking down a steep hill, and seemed to take a while to shut off. Although I was watching the o2 sensors on the tech2 because I could not find the FI plusewidth data item.

Does anyone have any good information regarding this topic?

Thanks

 

No one finds this topic interesting? Or is it that no one really knows much about it?

 

there's a lot of threads on this (usually referred as DFCO) in PCM/tuning as well as the HP Tuners forum.

I've used this feature on both my Olds and Camaro. The Camaro I tuned with the HP Tuner and enabled it to come on earlier and on more vacuum than stock, so when I'm off the throttle at highway speeds, it comes on and slows the vehicle down. It's great for when you're in traffic and the speed varies greatly, also for slowing down to an exit ramp.

 

Yeah, I like this feature. I don't think it really works since I've got my cam installed.

But yes, the DFCO does have the information I was looking for. Thanks.

 

yeah, the DFCO looks at MAP sensor values to determine whether or not to enable it. Typically an aftermarket cam will reduce engine vacuum at low RPM and idle, so it's likely not getting to those values.

 

put the post in the correct forum?? You'd likely get more responses...

 

Sorry Chuck - I didn't know this was an editable feature on these pcm's..

Thanks for the help Rhedalert