winklershop Posted September 18, 2014 Share Posted September 18, 2014 Hey guys I have a 1995 mack rd688s E7-427 dump truck, and the engine has been cutting out at higher speeds. I have no problem at low speeds with the engine running. I get up above 35...and sometimes I can get up to 50-60 but then it starts cutting out and cutting back and I get back down to 35 mph...I have no blink codes...what do I do? Quote Link to comment https://www.bigmacktrucks.com/topic/37125-1995-mack-rd688s-e7-427/ Share on other sites More sharing options...
carlotpilot Posted September 18, 2014 Share Posted September 18, 2014 fuel filters? Quote Link to comment https://www.bigmacktrucks.com/topic/37125-1995-mack-rd688s-e7-427/#findComment-260328 Share on other sites More sharing options...
R.E.D Posted September 21, 2014 Share Posted September 21, 2014 Boost leak? Mine did that beacause it had a penny size hole in the charge air cooler Quote Link to comment https://www.bigmacktrucks.com/topic/37125-1995-mack-rd688s-e7-427/#findComment-260588 Share on other sites More sharing options...
turckster Posted September 22, 2014 Share Posted September 22, 2014 Is there smoke when the engine is cutting out, like white smoke? Could be a broken spring in the fuel return check valve. Fuel pressure should be 28-44 psi Quote Link to comment https://www.bigmacktrucks.com/topic/37125-1995-mack-rd688s-e7-427/#findComment-260743 Share on other sites More sharing options...
winklershop Posted September 26, 2014 Author Share Posted September 26, 2014 ok so we did fuel filters and no change. no smoke. we get the electrical short light on the dash. we drove it some more and the only time it does it, is pulling a heavy load up hill. soon as you get the load off or on flat ground it drives fine. it drives great with no load on the trailer. Quote Link to comment https://www.bigmacktrucks.com/topic/37125-1995-mack-rd688s-e7-427/#findComment-261184 Share on other sites More sharing options...
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