Vmac3

We used to repair these axle stubs all the time. There is a company called PR Welding that will come out and weld new stubs on these meritor and eaton axles. It was quite interesting to watch, although the old man did not like an audience. After he finished stick welding the stub on, he would wrap it in fiberglass insulation. Hus welds were pristine. He would remind us to allow it cool overnight. Never had an issue with these when he did the repair. V

Would be nice to see what codes are in this. May have a J1939 issue. I know when J1939 is lost, the truck will not shut of immediately and will take 5 seconds to shut down. Never had a TPS cause an idle surge when the engine is cold. Usually if the tps is lost, the engine will default to 900rpm. The fuel system should not be checked at idle only, this should have been road tested under load with a manual gauge in the fuel system and then readings taken. That would have given you a more accurate reading. We really don't know if the fuel system is at fault still. Check to see if there is a rectangular connector on the driver side on top of the transmission, if it does run the truck and wiggle that connector and see if you notice a change in the engine. If it does then pull that connector apart, clean it with contact cleaner and put a zip tie around it nice and tight. Let us know what you find. V

Install a clear plastic fuel line on the return side of the head and see if there is air in the fuel. Ive seen the pickup tube in the fuel tank cause issues with sucking in air as well. Im not saying cups are not the issue but these engines didn't have the failures as the newer ones. V

Mack built a marine engine back in the day and called it a M-E7. This engine produced 650hp at 2300rpm. Its was 728ci with a mechanical fuel system. Never seen it in action, only heard and done some basic research on this bad boy. V

How is the suction side of the fuel system? You may want to do some trouble shooting first. They did have issues with the fuel return check valve getting stuck open. Is the check engine light on when this happens? May be a cam or crank sensor. Just sayin. V

From what I remember these trucks came out in 2005ish. They wouldn't be able to produce these in 2007 because of the emissions changes. These were US04 emissions. Mack was first to receive the redesigned engine which was the MP7 which is really a Volvo 11L. I remember working on these back in the day. They never really gave any issues, like the ones we have in 2007 to date. Just wiring and sensor issues. Cups never really gave any issues. I actually don't remember doing cups on these engines. I wouldn't mess around with it, in my opinion it s the better of engines in the MP series they have. V

They had issues with these valves/airlines. They had a bunch or service bulletins to address broken air lines. Back in 2010ish they released a service bulletin to block off the valve if it fails and reprogram the engine ECU. Usually what happens when these things fail is, when a regen is requested the DRV recirculates the boosted air and T1 temps will start to go up and turbo boost pressure will stay low. These failed like everything else that was bolted on these "newer" engines. V

You would be correct. When the system is in active regen (not sure if it activates in extended heat mode), the valve recirculates boosted air which causes less scavenging across the piston. Also is a controlled boost leak which makes EGTs higher. V

Fuel lines switched around on the fuel tank??

No they dont read anything until they are around 5oo degf.

Nox level is higher on the outlet than the inlet. Try an outlet Nox sensor and perform the regen. Make sure you reset learned data as mentioned. It is true that these sensors were and still are failing. V

What FMI are you getting. This will help with the diagnostics. V

I agree, Leave it alone. No knocks or clacking, oil pressure a bit low but nothing to worry about. Shorten the oil change interval with good quality oil and the truck will be fine. If the oil pressure drops below 15 then I would look into it. These engines are really reliable. V

You deserve the respect, because you serve the community with humility. I enjoy reading your posts. V

Awesome Joey!! V

What year is the truck? V

Thanks for posting your fix.

I had a customer with a D12D with 2 million k wanting an engine overhaul because it was consuming oil. So we overhauled the engine, replacing all the internals with new cylinder head, camshaft and injectors. Truck ran fine until we road tested it. Once under boost the cooling system was being pressurized. I ruled out the head gasket because I have never seen one of these head gaskets fail. Anyway, I used the Fleetgaurd combustion leak detector and confirmed combustion gases in the coolant. I didn't hook up PTT because it ran great at idle and the cooling system was not being forced out of the recovery tank. So, I took an educated guess and pulled out the injectors. Bingo, #5 injector had traces of carbon on it. Removed the cup and cleaned the mating surface. Using a pen light, you were able to see a very fine hairline crack propagating from the injector tip hole. Who knew? So for sure, Unexpected things like this do happen. Took it all apart replaced the head and the truck ran fine afterwards. With the original posters issue that has an egr delete, I'm wondering if the higher cylinder combustion temps and possibly injector timing changes are causing these engines to fail like this? Dunno?? V

Yes you are correct. I have never seen these head gaskets fail on a Volvo. The liners may be cavitated and a pin hole may have developed. V

It is possible to correct the gear backlash with this method but the injector protrusion will be an issue. V

You would be correct. These cylinder heads should not be machined because this will change compression ratio and injector protrusion. V

Sorry I am late to the party. How these compressions tests work is, the engine ecu measures the speed of the crankshaft while the starter motor is engaged. The ecu will see what cylinder is coming on the compression stroke by looking at the camshaft and synchronizing it with the crankshaft. Then the ecu will see which cylinder has the slowest speed during the compression stroke and compare the others to the slowest cylinder. If you do back to back compression tests, often times a weaker cylinder can sometimes be at 100%. This test should be used with a cylinder balance test. V

Here is the manual with the pump options. This is for a Volvo but its the same thing nowadays. V 291355435_VolvoSection9PTO.pdf

Had these welded before by a professional welder. No issues whatsoever! V

You have a PTRD-F pto, which turns counter clockwise when facing the back of engine the horsepower is 188 and 642lbsft of torque. V