Jake brake issues????

So...I have a 07 KW with a isx. I’m new to the truck and im unfamiliar with the Cummings engines. It seems like the Jake is not as strong as it should be. It has a 3 position switch but there is no difference between the medium and high position on the switch. The Jake at times seems to skip like it’s not on the high setting. The shop put it on computer and didn’t see any issues however did not road test it to see for them selves what’s going on. Any help would be appreciated. Thanks in advance!!

 

Is it by chance deleted? I've heard most everyone I know that deleted an isx, complain about the loss of breaking power from the jake.

 

The motor is untouched at this point with approximately 220,000 miles on it.

 

There are 2 solenoids under the valve cover. The front is for the front 2 cylinders the rear is for the back 4 cylinders. If the low setting works 2 cylinders and the medium setting works 4 cylinders and both solenoids activate all six cylinders if this is so then the electrical system for the engine brake is working properly. Does the Jake operate with the in all three positions? If it does then you may have a mechanical problem under the valve cover.

There are six rocker arms for the Jake and each one has a spool valve and spring retained by cap with a snap ring. The spool valves can leak or blow apart causing a weak Jake or a cylinder to not work on the Jake. The spool valves also act as detents and park the Jake rocker arms when the Jake is not in use. If the spring gets weak the Jake rocker arms may not detent and if they don't then they will clatter back and forth and loose the oil trapped in them. Once that happens the Jake will work but be weak.

I would recommend a Jake tuneup kit which is new solenoids and seals new spool valves and springs and caps and snap rings.

 

An 07 with 220K miles? Possible but not likely in my opinion. Probably forgot a 1 in front and a few 0’s at the end.

 

What would one of these tuneup kits cost?
Odd I commented on this one when it was new and now I am experiencing some Jake brake issues of my own, Karma I guess.
07 379 ISX 15 with 1.3 million mile. Ran to Memphis and they worked fine. Coming back no Jake regardless of setting.

 

I'm not sure the cost. All the kits I have installed came from a Cummins dealer.
I don't think a kit will fix your Jake if you lost all settings. More likely an electrical issue.
Does the cruise control work?

 

Cruise does not work

 

There are one possibly two brake switches and a clutch switch that I would check the operation of first.

 

Not sure what you mean?

I think my issue might have been I had the cruise switch on, not engaged but I have two toggle switches for Cruise. One turns cruise in and the other sets the cruise or resumes the cruise.

My Jake is a 3 stage and that switch is always set to 3.