RevCutActive for no obvious reason

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MikeyB571
Posts: 42
Joined: Sat Nov 26, 2011 12:05 pm

RevCutActive for no obvious reason

Post by MikeyB571 »

I'm mapping my car and hitting what has the symptoms of a rev cut at high RPM. But before the rev limit.

I'm not seeing anything untoward in the logs, no limp mode, no trips and its staying in 720 sync.
But the logs do show revCutActive coming on and off repeatably after 5000 rpm. The logs show that the rev limit is 7200 and that the rev limit active is always idle.

I just don't know why the ECU is enabling revCut.

Any help would appreciated, at the Dyno now.

MikeyB571
Posts: 42
Joined: Sat Nov 26, 2011 12:05 pm

Re: RevCutActive for no obvious reason

Post by MikeyB571 »

I've increase my rev limit on everything to 20000 and it's fixed the issue.

Any ideas what's going on

stevieturbo
Posts: 898
Joined: Sun Dec 07, 2008 2:04 pm

Re: RevCutActive for no obvious reason

Post by stevieturbo »

log it and see.

it should state the reason for any limiters or cuts if logging the right things.

And without any logs/cal to see...anyone here will be guessing.

and rev cut and rev limit are two separate features.

MikeyB571
Posts: 42
Joined: Sat Nov 26, 2011 12:05 pm

Re: RevCutActive for no obvious reason

Post by MikeyB571 »

Understood, I was a little flustered earlier as I was on the dyno.

Here is a log of the event.
2019-08-15 12-57-50 plus 0h04m05s S6#1097.SD
(345.91 KiB) Downloaded 75 times
Thanks for looking.

stevieturbo
Posts: 898
Joined: Sun Dec 07, 2008 2:04 pm

Re: RevCutActive for no obvious reason

Post by stevieturbo »

I can see it very intermittently becoming active around 5k, but as you say, it is logged as cut at being 7200rpm.

No limps or trips or anything though, very strange.

In fact...viewing again, the entire time above 5100rpm, both on and off load revcutactive is repeatedly switching between idle and active, even though rpm trace seems reasonably smooth above this level, although perhaps not quite at 5100rpm.

Definitely no cal switch reductions or something for the rev cut ? although it isnt actually being a full rev cut...because it isnt staying active.

MikeyB571
Posts: 42
Joined: Sat Nov 26, 2011 12:05 pm

Re: RevCutActive for no obvious reason

Post by MikeyB571 »

No rev reduction is set on any of the cals.

Rev cut was set to 8450 and rev limit set to 8000.
When I set all limits to 20000, so RevCut, RevLimit, all limp mode RevLimits, then the problem went away and I was able to continue mapping on the dyno.

I'm going to re-introduce the rev limit and then the rev cut and see when the issue re-appears, I'll report back on that.

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