JMack302 Posted February 25, 2020 Share Posted February 25, 2020 (edited) I have a 84 R model. It has the Mack dynatard engine brake. It used to work fine but hasn’t for about a year. I want to replace the wiring because it has become chaffed and broken in places. This is where I need some help. The wire come out of the firewall then hooks to each valve cover but after that I don’t know where it goes as it’s missing. Any help would be appreciated. EM6-237 engine Edited February 25, 2020 by JMack302 Quote Link to comment https://www.bigmacktrucks.com/topic/61131-r-model-engine-brake/ Share on other sites More sharing options...
Quickfarms Posted February 25, 2020 Share Posted February 25, 2020 What engine do you have? Quote Link to comment https://www.bigmacktrucks.com/topic/61131-r-model-engine-brake/#findComment-443696 Share on other sites More sharing options...
JMack302 Posted February 25, 2020 Author Share Posted February 25, 2020 23 minutes ago, Quickfarms said: What engine do you have? EM6-237 , sorry meant to put that in the post Quote Link to comment https://www.bigmacktrucks.com/topic/61131-r-model-engine-brake/#findComment-443697 Share on other sites More sharing options...
Quickfarms Posted February 25, 2020 Share Posted February 25, 2020 To the throttle switch on the injection pumpCan you post a picture of your injection pump Quote Link to comment https://www.bigmacktrucks.com/topic/61131-r-model-engine-brake/#findComment-443699 Share on other sites More sharing options...
JMack302 Posted February 25, 2020 Author Share Posted February 25, 2020 Quote Link to comment https://www.bigmacktrucks.com/topic/61131-r-model-engine-brake/#findComment-443702 Share on other sites More sharing options...
JMack302 Posted February 25, 2020 Author Share Posted February 25, 2020 Hooked it up to this connection. It works now but it stays on all the time including idle so I’m guessing that’s not where it goes. Quote Link to comment https://www.bigmacktrucks.com/topic/61131-r-model-engine-brake/#findComment-443705 Share on other sites More sharing options...
Quickfarms Posted February 26, 2020 Share Posted February 26, 2020 I was able to find this online and it appears to match what is left under the hood on my 1985 R These are the connections on the passenger side firewall Quote Link to comment https://www.bigmacktrucks.com/topic/61131-r-model-engine-brake/#findComment-443767 Share on other sites More sharing options...
mechohaulic Posted February 26, 2020 Share Posted February 26, 2020 opposite end of new wire ,is that going to ground? usually there is only one wire to pump which grounds it self. now a days they may be using the pump switch as an on/off to complete the circuit with two wires the pump switches were a royal pain in a -- -. brass tab inside always failed. if its staying on with red wire to ground, i'd say try adjusting screw on pump slightly. doubt wire colors can be seen that weathered. based on picture,14 R/G (red/ green ) should be from circuit breaker; 14 BR (brown) goes to pump switch to complete ground side ;14 B (black). to cyl heads. definitely don't want to open top cover with all that dirt around it. firewall connection pictures aren't the worse ever, not that there isn't chafing wires or connections wrong. brake works when grounded . unravel the tape see what it looks like. maybe not bad ,tapes only holding plugs together (ya right !!) wiring is always fun when someone else has been there before... Quote Link to comment https://www.bigmacktrucks.com/topic/61131-r-model-engine-brake/#findComment-443783 Share on other sites More sharing options...
Swishy Posted February 27, 2020 Share Posted February 27, 2020 Forgotten which way the brass threaded stud goes in or out to adjust wen Eb comes on/off remove wires loosen off top nut loosen off lower nut take note of where the slot in the brass stud is pointing screw out the brass stud as there is a screw driver slot on end of thread try one turn n C if th@ is better or 2 or 3 tignten nuts n fit wires wen 100% satisfied try not to use EB unless Donk iz @ operating temp cya Quote Link to comment https://www.bigmacktrucks.com/topic/61131-r-model-engine-brake/#findComment-443828 Share on other sites More sharing options...
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