Christian Wagner Posted February 17, 2021 Share Posted February 17, 2021 Howdy fellas, I’m typically just a reader on these forums but I’ve ran out of avenues to take. I have a 2019 MR with an MP7 engine. It has about 900 hours on it and 8,000 miles, “Lightweight” emissions equipment, and has ran like a champ up until about three weeks ago. Now, under load, In top gear between 1200-1400rpm it will stutter and run out of power accompanied by a puff of soot, if I let out of the throttle and ease back into it it will sometimes come out of it. If I don’t let out of the throttle it will continue to bog and throw a code for low common rail pressure. I have no way to monitor my common rail pressure. I have done all of the simple things such as checking fuel lines, replacing fuel filters, checking tank, etc. I plan on trying the pressure regulator next. Any help or tips would be greatly appreciated, not sure where to go after that pressure regulator. Ask any questions you want as well. Quote Link to comment https://www.bigmacktrucks.com/topic/65929-2019-mp7-low-fuel-pressure-under-load/ Share on other sites More sharing options...
Mackpro Posted February 18, 2021 Share Posted February 18, 2021 On common rail engines, there is a electric fuel pressure solinoid on the end of the fuel rail under the valve cover . It was a common problem and we had all ours replaced with a new updated part number solinoid and also harness. It caused low fuel pressure problems and low power . There is a bulletin on this from Mack and is on both MP7 and MP8 engines 1 Quote Link to comment https://www.bigmacktrucks.com/topic/65929-2019-mp7-low-fuel-pressure-under-load/#findComment-469210 Share on other sites More sharing options...
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