@m*m^2 delete cm871

[wellrun]

I've been looking at the @m*m^2 for the cm871 and I currently have it in a truck...I realized that the high oil temp and high coolant temp is disabled....why are these parameters disabled can I go ahead and turn them back on?

[Rawze]

the official versions, they are not totally disabled, they will still throw alarms the same way, but difference is that they normally will not shut down the engine over it. Alarms will still activate.

turning them on would be a matter of preference... some people like them to be on because they have hired driver who will not pay attention to alarms, or have bulk tank operations where they are away from truck for long time, it running unattended.


It should still give you engine lights, it just will not shut down or derate on you and put you on the side of the road.

on the other hand...

I can't tell you how many drivers I have met that say they hate it when their truck shuts down when the coolant gets a little low. They prefer ALL the shutdowns and derates disabled, most truck owners absolutely hate those shutdowns putting them in the middle of the roads unexpectedly for some stupid sensor problem... so they can decide for themselves if it safe to run the truck against a failing sensor, coolant a bit low, etc.

Some like shutdowns all turned back on,.. some would rather have them all off, but still give alarm.

Personally, having all those shutdowns and derates disabled has saved mu=y bacon more than a few times.. one time in dallas, slow moving traffic, in construction zone, nowhere to pull over, the low coolant, then extra low coolant went off,,,. i stopped in middle of road, saw I had coolant and continued on. -- another time when the oil pressure sensor went out,.. i drove it for several days with bas sensor till I could get home to fix it... Otherwise, I would have been shut down in the middle of the roads somewhere.

that is my own experience with it any ways.

Several people have said that there is absolutely little to no protection for the oil shutdown. Have had at least a dozen people over the years (with stock factory programming) say they lost an oil line and by the time the engine gave alarm for oil pressure and shut down, the engine was completely toast anyways,... that factory programmed 30 seconds of that stop-engine light before it shuts down is an eternity when you actually loose oil pressure. Personally, i think it should be like the old trucks where you had to press and hold a button in to bypass the oil alarm until it got up to pressure... those old systems would shut engine down mediately, and would actually save your engine from destruction.

same thing with coolant temp sensor... I have had a couple people now say they got a coolant temp alarm, gauge going hay-wire .. then suddenly the sensor read 0, like the engine was ice cold,,.. assuming it a=was a bad sensor for first reading off the charts,.. chattering, then going cold,.. they keep going,,.. all with factory stock programming. - 5 minutes later, the engine locks up because what happened was the engine lost all coolant, and the sensor could not read temp any more, and went to zero instead of shutting engine down. - Low coolant never went off, because they hard wired / bypassed the sensor electricly, because it was shutting the truck down needlessly in the past because of just the settings your talking about becomming so damn annoying.

-- Like I said,. it is a matter of choice, and very easily, it can be set to whatever someone's preferences are.

[wellrun]

thanks alot rawse....