Philip said:As far as I know there isn't one and there are no plans to make one.
To have a true Jake design. You have to interupt the injection sequence. On the 1st and 2nd gens being single injecter lines per cylinder. It would be hard to design and cost would be very high.
MMiller said:The old semi trucks with injection pumps just had a switch on the throttle linkage. When the throttle went to idle the jakes come on whenever the jake switch in the dash was on.