Jake brake problem

Before pulling the covers check the input wires. There is a lead that plugs onto the side of the jake(passenger side on my cummins). Then test for input from each lead. Get a friend to raise the RPM's with the jake on stage 3. Connect a voltometer to the leads and check for electric input. If you have power to all leads THEN its time to go inside. Could be an internal broken lead/solenoid/plunger......

 

The Cat setup is nothing like what the Cummins has. The Jake brake wires go through the ECM on a Cat. I would take 5 minutes and pull the valve covers and push on the soleniods to see if its mechanical or electrical. If the jake works when you manually activate it, get a voltmeter and see if there is any power going to the solenoid. I would check the clutch pedal switch for power too. Sometimes mine won't come on and I can pull up on the clutch pedal with my toe and it starts working again.
It might be a loose wire under the valve cover right where it conects to the solenoid too.

 

The soleniods will be easy to spot. They are about as big around as a half dollar and have a disc in the middle of them. Thats what you want to push down on to actuate them. They will also have one wire connected to them and are right on top after you pop the valve cover off. You can usually re-use the gasket, its kind of a hard plastic with silicone in the middle. Also the valve cover bolts are designed to stay with the valve cover when you pull it off.

 

Yep thats what I said neighbor!

 

Having the same issue with my 96 pete wondering what you determi
ned to be the problem

 

Cummings NT365 model 430 jake having same issue 1st stage not firing 2nd firing 3 stage only firing 2 valves changed soloinoid in first stage and checks wires and terminal everything us good checked check valves kinda lost at thus point

 

I'm having same problem, took covers off and tested solenoids, the one in front of engine does not engage jake only shoots oil from underneath. Anyone know what I should do from here?

 

if the oil is coming from the hole in the bottom of the solenoid, replace the solenoid. If not try to identify the location. what engine is it?