square tire Posted August 20, 2011 Share Posted August 20, 2011 Hello, i'm new to this site and was hoping to find some help in diagnosing this problem. I'm a truck mechanic for a concrete company and we have a '08 MACK MRU with MP7 engine that will shut down while driving. All parameters read normal according to VCADS pro tech tool. Engine shut down light appears on the cluster and beeper starts beeping, engine losses power despite full throttle application just before coming to a complete stop the engine shuts off but will restart right away. different codes are retrieved every time, we have replaced the low coolant probe, engine oil pressure sensor, and the engine oil temperature/ level sensor located in the oil pan. We have also traced a maze of wires looking for a short to ground or a broken wire. Any hints?My concern is, this truck is a concrete pump truck, the last thing I need is this thing to shut down while pumping concrete and decide not to restart!Any advice would be greatly appreciated. Quote Link to comment Share on other sites More sharing options...
rhasler Posted August 20, 2011 Share Posted August 20, 2011 What codes are you getting? Quote "Mebbe I'm too ugly and stupid to give up!" Link to comment Share on other sites More sharing options...
square tire Posted August 23, 2011 Author Share Posted August 23, 2011 this week i'm only getting a code for critically low oil pressure, last week was the same along with critically low coolant level, high engine oil temperature, critically low coolant level, also when the engine decides to shut down the red light beside the oil can emblem on the cluster begins to flash along with the beeping that I mentioned earlier. I'm starting to believe I would be better off with a match and a can full of gas! LOL Quote Link to comment Share on other sites More sharing options...
square tire Posted August 24, 2011 Author Share Posted August 24, 2011 today I might have made some progress, removed the oil pan again and noticed there is a clamp that hold the oil pump pick up tube in place and this clamp was broken, I replaced the "O" rings on the pick up tube and the oil return tube and replaced the clamp. When I started the engine it was showing 70 psi oil pressure pressure at idle, after an extensive road test the truck never shut down and no warning lights or buzzers appeared. I'll no more tomorrow after we send it out to pump cement. fingers crossed. Quote Link to comment Share on other sites More sharing options...
rhasler Posted August 24, 2011 Share Posted August 24, 2011 Goodluck. Did you happen to check for any broken or loose bolts holding the oil distribution housing to the bottom of the block? Quote "Mebbe I'm too ugly and stupid to give up!" Link to comment Share on other sites More sharing options...
square tire Posted August 25, 2011 Author Share Posted August 25, 2011 I pulled the oil distribution housing off completely to replace the "O" rings on the pick up tube and there was no broken bolts, they all came out easily and didn't appear to be streched so I reused them. Quote Link to comment Share on other sites More sharing options...
Wayne Keel Posted October 1, 2019 Share Posted October 1, 2019 My 2009 MP7 engine went down on low oil pressure. Dropped the pan and found the two bolts on the block to steady the oil pick up tube were laying in the oil pan. I was told that the O Rings in the pick up tube were probably bad and to replace them. Could those O Rings be the problem? I bought the truck at an auction and the engine was 7 gallons overfull. We drained it down to the normal oil level and it ran fine for a couple of hours and then would not start. Quote Link to comment Share on other sites More sharing options...
Elite Diesel Solutions Posted October 12, 2023 Share Posted October 12, 2023 hey there i got a truck that’s doing the same exact thing expect it’s got no light or anything that comes on before it shuts off. the speed just starts dropping and he loses throttle response. then it cuts off. he flips the ignition off and back on and the truck will crank back up and will continue down the road without an issue. this happens randomly and it seems like he runs fine up until lunch time and then it starts doing it. idk if it’s coincidental or if that’s when the trucks gets nice and hot and then it does it. but like i said, no codes, no lights, nothing Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.