turckster

Here is a PDF of MP7 oil psi issue check list. This should help you find the problem.

MP7 low oil psi check list.pdf

On 1/23/2018 at 5:59 AM, OJ Avery said:

We have an over heat solenoid on our mp7's, idk if it comes on all. We've seen a no start condition caused by this

All Mack mp engine starters are controlled by the engine ecu. The eecu provides the ground circuit for the starter relay. The purpose for that is to protect the starter from overcranking/overheating. If the eecu sees excessive crank time it shuts off the ground circuit to the starter relay for a minimum of 30 seconds. 

There are 2 solenoids, one at the rear of the oil base pointing down--that is the piston cooling jet control solenoid. The other is nearly at the rear but pointing to the frame rail--that is the oil cooler thermostat solenoid. Check for oil contamination in the connector, clean with electrical contact cleaner and see if the fault goes inactive. 

Seen this many times and almost every time they clear up after a road test. 

Many things could cause this issue from blown fuse to bad ignition switch, bad vehicle ecu or engine ecu. You need to check all fuses- ones under center dash panel and inside left side kick panel. Check voltage at starter relay w/key in start position, should be 12+ volts. If less than or nothing check ignition switch, I have seen the crimped connectors on the back of the switch be loose causing a bad connection. 

The engine ecu controls the starter circuit by providing the ground circuit for the starter relay. A couple things I see that cause this issue are low voltage to the starter relay, oil in the eecu connector cavity or low/no voltage to eecu. Make sure all fuses are ok, check for 12v+ to the starter relay with the key in start position. Check the eecu connectors and connector cavities for oil contamination--if so clean with electrical contact cleaner. It could also possibly be a bad wire from the starter to the eecu but that is rare-but it could happen. If you can activate the starter with a remote starter switch then you know the starter is ok.

3 hours ago, Mack Technician said:

Not a bit of sarcasm. I could not figure it out when I first looked at it. After looking at the operation it is crazy smart. 

I thought the same thing when I first looked at the inside of the common rail engine. Rather than a radical design change they adapted what they had, using 3 injectors to act as high psi pumps instead of using a mechanical pump. I thought that was cool. 

Looks very much like the training center in Dallas/Ft Worth

The sensor should have 100-200 ohms (usually 160 ohms)--measurement from the vecu connector. The sensor adjustment is 1 turn out after contact to the tone ring. If all of that is correct make sure the tone ring is tight on the yoke. When making the resistance check of the speedo sensor, wiggle the wiring to see if the value changes. 

I've been replacing a lot of the AHD (aftertreatment hydrocarbon doser) modules lately because of oil contamination in the air line to the module. The oil contamination causes the shut off valve inside the AHD module to fail. Remove the air line to the module, if there is oil in it you must flush the line, replace the air dryer filter and replace the AHD module air regulator valve (mounted behind the air dryer). Failing to do so will cause the AHD module to fail prematurely. 

Have you checked the egr diff. psi sensor ports on the venturi? The fault is for low or little flow so one or both ports could be plugged, which is common. If one or both are plugged you might be able to clean them out but eventually the venturi will have to be replaced. 

More than likely spun a rod bearing. Personally I would go the exchange engine rout. You get an engine with a year warranty that has new/reman components in it. I would definitely replace the oil cooler and take a close look at the turbo and air compressor. 

21 hours ago, Hobert62 said:

On my dads isx cummins when his pump went they said if the security  seal on the pump was broke they "can't" accept them for a core.  

For us (Mack/Volvo dealership) if the tamper proof seal was missing or cut then that would void the warranty (if one still existed). It would not affect core value. 

Fewer dealerships are repairing injection pumps anymore. Our pump stand finally broke down and the company decided to retire it. We rarely used it anyway here in the last 5 or so years. We rarely rebuild injectors because it's cheaper to replace with reman injectors. If we have to have a pump evaluated for repair we use a local injection pump service company. Most of the time we exchange inj. pumps w/reman pumps. The last in line injection pump rolled out of the factory about 20 years ago on a Mack. 

I can only assume that they see excessive wear or additional damage and that is why they may recommend exchange. You could remove the pump and have an independent pump repair shop look at the pump. It'll save you some money in labor and parts but since I work for a Mack/Volvo dealership I feel dealership work is better quality from a reputable dealership. 

A few pointers for you- the main bearing in #2,3,5&6 are the same top and bottom. Main #1 shares the same bottom bearing as others but the top bearing is different.  The tang is located in a different spot and it will go into other locations. You will loose all crank thrust if that happens.  #4&7 mains are similar as well so be careful there too.

#5 buttress bolt next to the air compressor can be a pain to get at. If you have a Bendix air compressor you can remove the compressors lower cover and get at the buttress bolt easily. If you're replacing the oil pump make sure the drive great is the same. I've seen customers install incorrect pump assuming it was correct and shred the aux shaft drive gear. 

Good luck

If the governor is plumbed correctly the unloader valve may be stuck in the air compressor head or the wet tank/signal line could be plugged. 

The air governor has 3 ports-unloader, exhaust and reservoir. The reservoir port goes to the wet tank, the unloader goes to the air compressor unloader and the air dryer purge port, exhaust is open. The air governor gets its signal from the wet tank. Once the pressure in the wet tank reaches 125-130 psi the air gov.  sends an air signal to the air compressor unloader and dryer purge port. Once the air pressure drops a certain point in the wet tank, the air gov. dumps the unloader signal and allows the air compressor to build air pressure. 

When I am diagnosing purge issues i install a gauge into the unloader port and a gauge into the reservoir port on the air governor, that way you can see what the air pressure is in the wet tank and what the air gov. unloader pressure is (should be same as system pressure). If everything looks ok, make sure the air lines to the air compressor and purge valve are not plugged and will hold pressure. If all looks ok there as well then the issue most likely is the air compressor unloader valve being stuck. 

On 7/27/2017 at 5:25 PM, casspace said:

I have a 2012 CHU 613 with mp8.   We carried to the dealer and they say the oil level sensor in oil pan has gone bad.   Which let oil travel up the wires to the computer and ruined the computer.    Then they tell me that its a common problem.   I have had this happen with an 05 Granite and was assured the problem was solved with antifreeze level sensor.     I was told my truck too old for any assistance from Mack.    I have a 2012 Granite that the injector cups went bad on.   Another common and known problem.   I even spoke to higher up people at Mack with no assistance.  Said my truck was too old.    If this was Ford or GM there would be recalls and lawsuits.   Any ideas?   Plus while they a trying to figure out problem I am getting charged 120 per hour for diagnostic fee.   We barely get 80 an hour for the trucks.     Cass

I've replaced tons of engine harness's because of oil contamination, rarely have I seen a eecu go bad because of oil contamination. Not saying it doesn't happen, just rare. The coolant contamination on your '05 Granite probably caused the eecu pins to corrode-different issue. When we replace engine harness's we also replace both oil pressure and piston cooler oil pressure sensors and the oil level/temp sensor. Also, we install jumper harness's on the above sensors as a precaution-in case one of the sensors fail and leak oil. The jumper harness will prevent oil from leeching into the main harness. 

The truck is 5-6 years old depending on the delivery date. Even with an extended warranty I think you would be out of luck. There are a few issues with the mack/volvo engines but I don't care what you buy, every manufacturer has their problems. 

Did you use Tech Tool to verify the egr was not flowing  or did you remove a egr pipe and verify no flow? We/I use a zip tie to attach a nitrile disposable glove to the egr side of a pipe, start the engine (egr valve unplugged). If the glove expands and pops the egr valve is bad. You should be able to hold your hand over the pipe with little resistance if the valve is good. We see this a lot with trucks that require frequent regens. 

Fuse 17 powers the cruise control switch. Its a 10 amp fuse located in the upper bussed electrical center.

On 1/23/2017 at 8:47 PM, luke andres said:

so now im confused       do i plug off the air line or do i supply it with air?    and yes it does go from the 2080 transmission to the engine manifold

I'd plug it. Like I stated above, it's main purpose was to limit torque in revers and low gear. 

On 1/14/2017 at 9:39 PM, luke andres said:

so i swapped transmissions on my 91 dm mack 300 em7 engine       there is a air line that went from the mack 2080 transmission up to the intake on the engine       where should i tap this air line into on the truck as the eaton fuller 8ll doesnt have a place to put it            also what does this  air line do

As far as I remember E7 engines did not have bimba valves, they had lda valves on the back on the injection pump. The air line that went to the t2080 trans was a manifold psi dump. When the trans was in reverse or low gear(s?) the valve would dump manifold boost to protect the driveline from damage.  I'm not sure how they were plumbed on vendor transmissions or if they were there at all. I would remove the line and fitting and install a plug in the manifold. 

This PDF check list is for  SPN5394/4094 faults but G/D will basically ask you to perform the same tests for a 4094 fault. Any type of contaminant that gets into a SCR will affect its performance-such as fuel. soot or coolant. Once the SCR is contaminated then it is bad. If everything checks out ok and you continue to have 4094 faults then the SCR may be the issue. Also, make sure all software is current in all ecu's.

SPN5394-4094 SCR Sys. Perf..pdf

4 hours ago, ERoberts said:

turckster

OP is a pre DPF operator. The issue was very prevelant to our CXU series series but if the SB is followed yo should have no other issues.

Being a CXU chassis and a 2008 model, this chassis is equipped with a dpf unit. The service bulletin addresses alignment issues of the flex pipe and proper repair. The customer complaint is expansion of the flex pipe. The only thing that comes to mind, for me, is excessive back pressure. Not meaning any disrespect, just saying. 

If the flex pipe looks "expanded" or pushed out, it is most likely cause by excessive back pressure. Either the dpf is plugged or the cataylist is plugged or both.  You need to find out why this happened. A face plugged cataylist is usually caused by a poor flowing 7th injector. 

Check the fuel pressure, should be somewhere around 65 psi at idle. Usually when the fuel tansfer pump starts to give up the ghost the engine is hard to start, has white smoke in the upper rpms.  The drive gear is most likely spinning on the drive shaft on the transfer pump.  You might check the oil level as well, it could be diluted w/fuel--another thing the fuel transfer pumps were notorious for.