Dropout at idle

[walterclark1]

Sitting at the top of Mt Washington last weekend, waiting for the cars in front of me to move out and with the engine warmed up and idling I began noticing these RPM drops that occurred about ever half mniute. I captured a log which contains 2 of them. It appears (in the attached log) that at about 9 seconds and about 36 seconds Accel Enrich, Duty Cycle and PW all drop to zero for around .27 seconds, then return to normal. I dont see anything (in my log) that triggered them. Anyone have an idea what would set that off, or have a suggestion as to what else I should monitor to zero in on it?

[billr]

What was the altitude there?

Edit: Looks like that fuel cut is related to AE, but I couldn't see a log of TPSdot.

[walterclark1]

Thanks.

The elevation at the parking lot at the summit is about 6200 ft. Correlates pretty well with the MS3 barometer reading.

Yes, TPSdot is one of the many things I haven't been logging. I can add it. Any others?

Of course who knows when the car will get back to Mt Washington...but I have another hillclimb next weekend at Burke Mountain in Vermont so I can look for this then (if it occurs).

Little drive to the top last Sunday...https://www.youtube.com/watch?v=4bG6By3if7Q 110th anniversary of the first auto race to the summit.

[Matt Cramer]

It looks like an overrun fuel cut - what happens if you turn the overrun fuel cut off?

[walterclark1]

I hadnt thought of that as a possibility but now that I looked at it again and read the descriptors it looks like I am using over-run fuel cut-off wrong and at least need to reset the values per the suggestions. I will try just shutting it off for now and see if the situation disappears this next weekend. Thanks.

[walterclark1]

Shutting off the over run fuel cut seems to have eliminated those idle fuel cutoff's. For now I will just leave it off as otherwise I dont see any ill effects from doing so.