CmLandWorx

Replaced the pyrometer with one from Mack and still no change in derate. Still not registering boost. im guessing my next step is to replace the ecm or send it off to have it rebuilt.

Got the new harness in, truck is still having the same issue of not registering boost pressure. about 5 min into a test drive I did get high exhaust temp warning and the gauge was maxed out. could the pyrometer shorting out cause the intake manifold sensor to not work?

I was able to get a harness, should be here today. When putting the valve cover back on are there torque specs for the bolts and an order that they should be tightened?

here are the original and updated part numbers for the wiring harness Original 20844867 New. 21401681

What green stuff are you referring to? And other than a little oil on inside of the connector that harness looks good other than road grime and grease on the outside.

That had oil in it as well.

Honestly the section under the valve cover looked and felt better than most of the rest of it.

Understood, does anybody have a line on a new harness? Only one I can find only is from buyparts.online and I’m skeptical of the site. Mack said that it was a national back order and it did not give any type of estimated in stock time frame.

So I got the harness out, it’s soaked in oil from where it passes through the valve cover, called my local mack dealer and they said it is on national back order, also can’t find it online any where. Would cleaning the entire harness and putting new loom and tape on it (essentially rebuilding it) be a viable option or do I need a new harness?

How hard is it to pull the wiring harness out?

No I cleaned the plug and wires going back into the harness, when checking I have power moving through the wires going from the boost sensor to the ecm plug on all wires. could it be on the wire that goes from the ecm to the dash cluster?

No it still is having the same problem after cleaning the oil out. I did that 2 days ago.

I have an there was oil in plug A and I cleaned it out as well as a good bit of the wiring harness leading to it

I have an 07 granite CTP 713 dump truck with the MP7 motor and a mack manual trans. About two weeks ago when returning from running all day the truck derated. When checking the codes they were all random low voltage electrical codes for different sensors in the 5v sensor system. I fix about a dozen or more chaffed or damaged areas in the harness. My intake manifold gauge isn't working, as well as my exhaust temp gauge. I replaced the intake manifold gauge, and it did not fix the issue. The only code I am getting now is a generic low voltage code for the entire 5v system. I have checked the voltage at most of the sensors in the system and it is at 5v. One or two of the sensors were only getting around 4.7v. The truck ran ok for about 8 hours last Thursday and has since derated again. Looking for the wiring diagram for the truck if anybody has it or any ideas on next steps to take to attempt to get the truck back working.