Mackpro

Also is this a MP7 or MP8? 

Looking to get you a part number here shortly 

There is a 12 wire connector/harness that plugs into the chassis harness under cab . This is the manual transmission harness. It’s for the speedo sensor, reverse light switch , transmission temp sensor and PTO. 

First make sure 20 amp fuse/breaker is installed at fuse 42 in fuse box by clutch pedal. More info to come 

As far as Corporate helping dealers with issues like this ( change overs as they call them) it’s non-existing. They will set up the data files and if you lucky they will give the dealerships a Vin of a very similar truck as yours but with a manual transmission. Then it’s up to the dealership to go through each page of the parts look up and compare what’s different, from fuses, breakers , relays and harnesses. Been through similar situations with them years ago. They don’t make a parts list or how-to on things like this. 

4 hours ago, KKRT said:

Thanks Mackpro. I appreciate the info. We'll check the crank sensor tomorrow.

Concerning wiring harness, are you talking about changing the main engine harness, or are you talking about a transmission harness?

It’s a separate harness that plugs into the chassis harness on top of driver side frame rail. I’ll see if I can get  some pics in the morning. I’m thinking the Allison harness is separate and goes directly through the firewall with it’s own harness. 

The 1400 rpm is the default max RPM when there is a “Speed Error” . I always set this to 2150 in the Parameters when setting up a truck. Mack never really explained which speed error. I always assumed it was crank or cam sensor. When the flywheel was changed it’s possible the crank sensor could have been damaged as it reads off the notches on the flywheel. The truck should still start. There is a different wiring harness for manual transmission trucks . Don’t use the Allison harness 

I just worked on a 2006 Volvo VNL with the pre-emission D-16 engine. I didn’t think to look at the HP rating. It seemed to run pretty strong though. Volvo pushed the VNL as their heavy haul truck with many different engine options for many years. After the Mack Titian and MP-10 was discontinued in the US , Volvo pushed the VNL again as a heavy haul truck with the D-13 500HP/1900 ft pound torque or the Cummins X15 565HP/1850 ft pounds of torque. The Mack MP8 is maxed out at 505 HP/1860 foot pound of torque. It seems the Mack 505 Plus ( 1900 foot pounds of torque) is no longer available. The 505 Plus was a beast but seemed to cause some weird vibrations when under long hard pulls in the CHU trucks I worked on . I believe the 505 plus was available between  2014-2016 and pre-common rail engines in 2017 . 

On your oil level/temp sensor. It’s the same one that’s used in all MP engines. Original part number is 21042447. That part/number has been updated 5 times over the years since 2008. The new number is 23285701. And apparently there is a national back order on them . 

I even found my harness I made up to test it. What I have found is the rubber insulation grommets that the ecm bolts go through seem to shrink over time and this causes the ecm to vibrate/shake and causes the ecm to fail. 

The power and grounds are in the “B” connector which is the bottom connector on the ecm. Pop the cover off to tap into the wires . 

208 degree coolant temp should equal 257 degrees oil temp according to Mack. The max is around 270 best I remember 

The fuse box down by the clutch pedal is know to get water in it . Do much so that they had a major recall on several thousand units from 2008 to around 2012. Sadly the CTP and CXP were not part of this recall even though the design was basically the same as the CXU,CHU and GU trucks. However the CTP/CXP fuse panel has a different part number than the 2008 and up trucks. Pull a couple of the bottom relays and if there is white crusty residue on the pins then water has been in the fuse panel and possibly needs the be replaced 

Best pic on the Internet I could find . I circled it . 

4 hours ago, worellana88 said:

Thanks Mackpro so I’ll take the covers off of the panel there at the pedals shake those wires and check on the firewall plugs too. I replaced ECM and Ignition relay today beside clutch pedal. Cut off 2times all day today and sputter one time like it was gonna cut off. Hours were 12111 when it cut off when I cranked it back up it was at 12107🤷🏻‍♂️

I’ll try to get a pic of the problem connector. It’s under the hood around the foot valve area . 

The dash cluster is not needed for the truck to run and drive. Drove several around the lot with cluster removed.,  The 04 emission MP7 in the CTP and CXP was a a little different as it was only made for only a little more than  a year. The wiring is a little different than the 2008 and up MP trucks. Power to the engine Ecm comes from the fuse panel by the clutch pedal.  Fuse 38  and wire # is F38A2. Power comes through the top connector on the outside of the fuse box , PIN number A . This connector is called the EPDME. It then goes through connector CIEC pin A , this is a 16 pin connector around the foot brake valve  area. This is the usual problem area. With the engine running. Shake and twist this connector. 

The  CXN/CHN cab is also 6” longer than the CH and CX cabs from the 1989 through 2003.5 years. It seems the “bigger “ truck drivers could not slide the seat back far enough. Oddly enough the old short CX/CH cab was brought back into production for the MD series of truck that are being made today. 

5 minutes ago, Joey Mack said:

Oh hell,  Happy Birthday..  I didn't see it on the list yesterday..  

Thank you sir! 

20 hours ago, Joey Mack said:

Yep,,, still goin,  No big party, just a bunch of Bud's sayin' hello.. 

Happy Birthday! I think we have something else in common other that working on Macks, 

You can get new injector harness ends and pins and repair your harness . Bulletin attached 

injector harness.pdf