CM870 Jake Brake Issue

[Rawze]

(03-19-2021 )Psuce1 Wrote:  The engine makes about 15psi of boost when the Jake is on. No change in boost pressure between stage 2 or 3. It makes the correct amount of boost under load but I have not checked for leaks. I am planning on doing that though.

Stage-3 jake on the 870 is usually about 26-28 psi at 1600-1800 rpom range.

the only differences between styage 2 and stage 3 is more restrictions beign commanded by the turbo.

-- possibly ...

* bad programming? or incorrect program for the CPL?

* Turbo was replaced at some point with incorrect model number (has wrong exhaust impeller in it for the CPL engine it is)?

* Turbo controller or control arm acting up?. 870's notorious for this.

* Problem with air supply line going to turbo?

- Can't rule out a jake solenoid or control circuit for one is bad either. Maybe try manually switching them on one at a time and see if they are operating correctly?.