Chase1210

On 2/13/2025 at 10:23 AM, The Heinz said:

There's an overflow valve on the front of the head, I think on both MP7 and MP8. Looks like the below:

this is the same on a 2010 MP7 I assume?  Do you have the part number handy?  

Which of these is the level that the rear end oil should be at? I assume the higher one??

6 minutes ago, fjh said:

If your truck is deleted it makes it harder to diagnose! It can be the turbo causing this! The vgt may be stuck! if the egr is corked then possibly the vgt is stuck but not knowing the fuel pressure leavse you grasping at straws J pro is one I haven't worked with it Macpro may chime in and lead you to a better option I am not a guru on these so your talking with the wrong guy! If the turbo is stuck it will not throw a code period its one of those gut feeling things!

At one point in this trucks life it had a brand new turbo/vgt, still had no boost.  Then it was discovered that the egr was stuck open.  Hence the egr not being the problem anymore. ...very frustrating

38 minutes ago, fjh said:

Hate to say it but you’re chasing your tail without a computer! You need to know what that fuel pressure is and if the egr valve is closing as it should! Also if the mass flow is working correctly! Do you have codes engine light on ?

The EGR isn't the problem 😉...

No codes, no lights. What is a good computer or scanner I can buy that will work with this truck that doesn't cost $1000?

On 11/6/2024 at 9:07 AM, fjh said:

So you think its a fuel pressure problem but it could be something else!!?

I have already checked all the potential boost leak spots pretty extensively.  I suppose the CAC could have a leak somewhere that I'm missing down low where I can't really see.  After I was unable to find a boost leak I kind of switched gears to thinking it was a fuel problem, but I did not find any fuel blockages anywhere when I swapped the filter housing.  How can I check fuel pressure without a computer? Where would I tie a mechanical gauge into the sytstem?

this was my problem.  that check valve goes on the front side of the housing.  trucks running!  still doesn’t have sh** for boost tho.  max 25 psi.  wtf!!

15 hours ago, The Heinz said:

It certainly helps! #4 should be the return to the pump, Impact describes it as "FUEL FILTER BRKT-FUEL PUMP," while #8 should be the feed line from pump to filter, described as "FUEL PUMP-MAIN FILTER." 

Both of those banjo bolts use the same washer, Mack #20852765. The overflow valve according to your VIN is #21458307 should you need it. 

Sorry for the late reply, I'm now a Front Counter Salesman, so I am much, much busier than before. I've already had the privilege to order and quote parts for several older Macks, including an 80's DM. 

what position on the housing should the overflow valve be in? i can not get this thing to run.  i have good fuel flow from the tank when i pressurize it , but truck will not stay running and hand primer loses its pressure after every attempt to start 

1 hour ago, The Heinz said:

It certainly helps! #4 should be the return to the pump, Impact describes it as "FUEL FILTER BRKT-FUEL PUMP," while #8 should be the feed line from pump to filter, described as "FUEL PUMP-MAIN FILTER." 

Both of those banjo bolts use the same washer, Mack #20852765. The overflow valve according to your VIN is #21458307 should you need it. 

Sorry for the late reply, I'm now a Front Counter Salesman, so I am much, much busier than before. I've already had the privilege to order and quote parts for several older Macks, including an 80's DM. 

I really appreciate it.  Hopefully I can get it sorted out in the morning.  I may have some more questions for you! Thank you!!

25 minutes ago, The Heinz said:

I didn't have a VIN for a 2010 CXU with an MP7, but this is from a Granite of the same year with an MP7. Number 10 down there is an overflow valve on the return side, I don't remember if that can cause your issue or not. We never reuse these seals, but we are a dealership, so take that as you will. 

Thank you! That looks more like what I've got.  Now...

(3) Tank to ECU.

(17) ECU to filter housing

(12) Return from head to filter housing

(4) and (8) to and from filter housing to pump, but which is which?

My vin # is 1M1AW02Y1AM011833 if that helps?

Hi all,  I have a 2010 CXU with an MP7.  I replaced the fuel filter housing and now I can not get the truck to fire.  I've tried all the things you would normally do.  Now I'm convinced I may have a line messed up or a banjo bolt.  I noticed as I was putting in back together that 1 of the bigger sized banjo bolts is bigger than the others.  It has same threads but is a bit longer than the others.  Does anyone know which line the bigger bolt goes go? I've attached a diagram of where each line goes and this is not how my lines are routed.  Does anyone know if there is a different diagram with the routing different than this?  Everything was original when I took it apart.   When I pump the hand pump, it will get hard after 15-20 pumps but then after trying to start the prime seems to go away, that is why I feel like a line may be wrong. Maybe someone could post some pictures of there housing and lines so I can compare to how I have them?  Thanks

Hi all, I have a 2010 CXU613 with an MP7, what do you all recommend for a scan tool?  I need something to read fuel pressure but will use for other stuff down the road.  Basically looking for a all around universal scanner, that will talk with my mack.

Hello all, I'm looking for a driver side rear cab corner for my 2010 CXU.  There are some rot holes that I cut out, and instead of making them myself I was hoping to just weld in a new corner.   I called mack and they wanted 800+$ for the whole corner, which I do not need.  I only need the small section behind the marker light and under the grab handle.  Thanks!

Hello all, I'm looking for a wiring diagram to find where the wires go to from the boost pressure sensor.  Truck has no boost showing on the gauge, just 2 dashes like this "--".  I feel plenty of boost coming out of the hole where the sensor goes, and also replaced the sensor already.  Truck has no power at all, so I need to find where the wires go and hopefully I can find a bad one.  Motor is an MP7, Thanks  

On 1/12/2019 at 5:06 PM, Rockwell said:

Just in case it helps another down the road...

Problem Solved. Engine harness behind engine fan had a short in the 5. volt sensor supply wire. 

1 beer for fjh! You called it. 

i have this same issue with my mp7. can anyone be more specific about where to find this wire? what color it is ? anyone have a diagram?  thanks!

Anyone have any ideas?  Can the truck be derated without throwing an engine light? It doesn't seem to have nearly the power that it should.

Hello everyone, I have a 2010 Mack CXU613 with an MP7 in it.  Has less than 500,000 miles on it.  I bought it a year ago and have had these issues since I owned it, finally getting around to fixing stuff.  In the year I've only put about 3,000 miles on it.  Here is my list of problems: 

-lower power than I would expect it to have. but I've still been able to put 3000 miles on it grossing 80k or more.

-boost maxes out at 20 PSI (on the dash) fully loaded with the pedal all the way to the floor.

-sometimes loses fuel prime overnight (more often than not)

-it always wants me to do a manual regen (I've tried manual regen numerous times, it will complete a regen and light will go off briefly then tells me to regen again)

-if it sits an idles for longer than a few minutes it will start to do an odd, off-balance idle.  It will stay like this until I bring RPMS up.

Here is the list of things that have been done to try to fix some of these issues(that haven't made a difference): Brand new Mack 7th injector was installed, DPF removed and cleaned, fuel filters changed, new boost pressure sensor installed.

Any help on where to go next would be appreciated.  Thanks