Syvecs Forums

Have had a surprising situation occur today with a couple of 'lean on load' limp activations - at first I assumed it to be a dead WB02 (as I had a ton of these at one point) but it doesn't seem to be so.

Mu lean on load trips are:

Engine Speed > 3000 rpm
TP > 70%
MP > 1100mBar
AFR > 13.52


The first trip was valid (though I haven't figured out why this would suddenly happen)

lam1 13.6
map1 1274
rpm 4518
TPS 97.4


But then I got a bunch of limps that don't 'fit' the requirements during the next 20 seconds or so eg:

lam1 11.2
map1 1945
rpm 4500
TPS 59.9

I Can validate the trip activated from recLimitActive = Active at these numbers - happened in the last 10 minutes or so of a 40 minute journey just after sitting idling for 34 secs

Any thoughts would be much appreciated.

Post a log.

And what time duration have you set for a limp to occur ?

And is it actually Limpmode - Leantrip that is active ?

Log attached.

Limp duration is set to 400ms

Logbook shows last limp mode cause = "LEAN TRIP"

..bit confused here - I have slightly modified transient fuelling (positive decay) after experiencing this as I do note I have a rich followed by a lean spike after snapping the throttle open - but don;t think this is related - beenon this cal for some time now.

Additionally (and annoyingly I've lost the log) on the return journey that day I was seemingly permanently in limp (limited to 4500 rpm) even at very gradual throttle openings - after a stop and refuel - this 'went away'

Will have to gather some more logs...

you arent logging limp mode to see when it occurs and what it is saying ?

400ms is also a pretty short time period, I'd lift that to 1000ms or so

Cheers - and no I'm not and I probably should be (is that revLimitLimp?)

The only Engine Trip i have currently enabled is the Lean-on-Load Engine Trip - the logbook is indicating that was the limp reason.

Interestingly I took it out for a run yesterday and no limp again (which is good but frustrating as I've not been able to nail the issue down).

It's actually in a rather odd place now that I look at it lol

Or to find it....Config, Goto Logging item and search for limpmode
But increase the time for a trip to activate to around 1000ms. 400ms could muck up misfires, traction loss or other irrelevant events that arent really lean on load.

I've my trip set at 12.1AFR on boost etc and never once has this been tripped when it shouldnt, even when targeting 11.8

Thanks! That is not at all where I expected it to be!

Have gone to 1000ms - I didn't consider those other events that might 'falsify' a true lean on load - good point.

Caught this in the logs this morning - looks like I have a failing / failed LSU 4.9.

Interestingly i did no realise once tripped the trip remains in place - until I imagine ECU power cycle?

log attached:

the trip will remain in place until either yes a power cycle, or you turn to a calibration where the trip is not active and then back again.

I leave all safeties off on a calibration, just in case for some reason I might want to manually override a trip.

lambda is all over the show on that ?

I presume...hope you're closed loop settings arent allowing too much corrections based on that erratic information ?