CM 870 Engine Brake

[Rawze]

(03-22-2022 )Truckdriven Wrote:  ...
The minimum speed in Insite was set to 0 and with no vehicle speed input this caused the ecm to not command engine braking because the vehicle speed was at the minimum speed for engine braking

Just some words of wisdom ...

- I have seen ISX's destroy themselves when some idiot has it all set to instant engine brake and the engine is not fully warmed up, leading to a piston striking a valve. This especially on a fresh inframe. In fact, for the first 50k miles or so.. a person should not even be using the engine brake on their ISX on its highest setting until the head has had time to settle and a second over-head valve adjustment (the one recommended at 50k miles after an inframe) was performed after an inframe.

- I have also seen ISX's destroyed because of a sudden mass inrush of extreme cold air after the engine is real hot due to labouring up a hard to pull mountain .. and someone suddenly let off of the throttle to shift .. and that engine brake kick in too fast because of zero delay .. causing a piston to strike a valve too.

therefore ...

My own recommendation to protect someone's $40,000 investment (their engine) is to ... Set the minimum speed for the engine brake to be set to above 3 or so mph to protect the engine. It should also be set to a minimum delay of 5 seconds before it comes on for the same reason... and if that truck drives thru high mountains and winter extreme cold areas, then it should actually be set to about a 10-20-seconds delay minimum to protect the engine.

I know people get away with that 0-delay engine brake and that instant on .. but it really is risky (especially so on a new head/fresh inframe) and can be hard on the engine under some conditions ... just saying.