Mackpro

The first MRU frontloaders we sold back in 2008 were melting the plastic worklights and anything that was not made of metal under the cab protector. The bed company usually had a hole in the cab protector for the conventional muffler pipe to come up through. They were afraid that trash would fall through the hole onto the hot DPF and catch fire. So they put a block off plate over the hole. Now the heat from the DPF when regening was trapped under the cab protector and started melting anything near by. As per Macks instructions we removed the block off plate and put a piece expanded wire over the hole to allow the heat to escape and not let trach fall ontop of the DPF. Thoses 3 trucks are still running fine today with no issuses. However with the SCR now added and the different position of the exhaust piping thing are quite different. And as everyone said it could be a cracked filter.

Your about right on the RPM's as Mack recomends 1600 RPM cruise speed for the AC 350, 400 ,427 and 460 ( P and E models). The AC 330/350 and 355/380's recomend 1500 RPM. The 120,000 LBS,s might be the killer, our coal hauling guys down here that haul that weight get about the same MPG as you, They bought some CHU's with MP-8's and the 100 extra cubic inches helped their MPG by almost a full mile per gallon if not more in some cases.

also forgot, here is the cab height settings as well. cab height.pdf

Here is the actual Mack service bulletin, read very carefully as not all are the same and different frame heights on some models make a difference. sb136012 air suspension.pdf

Replace the boost pressure relief valve on top of the intake manifold elbow if it hasn't already. Have the complete intake manifold, piping and after cooler pressure checked. Get the "Step 12B program ( throttle responce program) installed at a dealer. Get the valves adjusted and replace the rocker arm hold down bolts with the newest part# ( could save u a $4000 cam job). If single exhaust replaced the muffler, at work I have the Walker or Donnelson part #(cant remember which brand) of a good cheap high flow factory fit muffler that is quiet but flows alot better than the factory. We have had good luck with it in MPG in some over ther road trucks. I'll post it tomorrow. Run a clean air filter and make sure the hole in the hood matches the hole in the air filter housing, make sure the rubber boot is on the opening on the air cleaner housing. If equipped with a fuel heater or a Davco fuel filter with built in fuel heater, install coolant shutoff valves and keep them shut off till near freezing. We have seen good MPG gains in the summer by not super heating the fuel. Mack now puts 10/30w motor oil in all their MP engine due to MPG gains but I dont know if I would change unless a total rebuild or reman engine just installed. The muffler I was talking about is a Walker part# 2191-m100436. It's the exact same size as the orignal and will bolt right on.

Remove the fuse box cover and turn the key on, to the left of the fuse block in the dash you will see 4 relays (not plugged into the fuse box) , the 4 wire plugs that plug into these relays are labled ' power relay 1" through " power relay 4" . 2 large red wires and 2 small wires on each relay. With key on check each red wire and it should have 12 volts on all red wires. Its hard to get to the red wires so I have a small 'U" shaped stiff wire that slips on my volt meter so I can reach them eaiser. If no voltage on any red wire then voltage problem from starter to cab. If only power on only one red wire per relay then key switch /fuse is bad or the relay itself is bad or the cab ecm (VECU) is bad.

Here's the free diagram off the Mack Trucks website, under service and e-media, lots of free info in there. http://www.macktrucksemedia.com/ProductDetail.aspx?ProductId=6547&GroupId=412 Its a large download. Just click on view file and its free

I was thinking there was a small fuse box in the sleeper that controlled the sleeper stuff.

I was just at MP engine overhaul class in Atlanta for a week with a guy from Mack of Nashville and a guy from Watt's Mack. Small world, we really never spoke of this Forum so I dont know if any of thoses guys are on here or was I in class with Staxx.

Go to "macktrucks.com" then click on "parts and service". Then in the middle of page click on "mack emedia center". In the "keyword" space type in 8-213 and hit go. then click on the red "8-213" and then hit "view file". At this point you can save or view the entire troubleshooting manual for free, the later print it out if you want. Almost every manual, bulletin and guide mack ever produced is the the the E-Media for free. Most people dont know that, us dealers use this alot! This code is MID-128 PID-412 and if the F number (FMI) is 0 the your EGR cooler is clogged with soot and needs to be washed out.

Just be sure to check the oil cooler inlet screen as it causes all kinds of coolant push, over heating and ECR cracking. SB215036.pdf SB214056.pdf

Its a MR688P built on 4/16/98 and has a E-7 350 with a manual fuel pump with an Allison HD 4000 trans. It has a 18-20K pound front axle but it doesnt say what rear spring weight is. The rear spring pack is a 12 leaf with a large helper spring pack on top of that . Thats all I could figure out , hope it helps.

I have see just acouple of ECM's that got filled up with oil, kinda rare but it could happen. We had an older MP-8 that had low voltage to 7th injector and found that the driver side windshield was leaking water into the fuse box in the kick panel and was causing low voltage. I didnt work on this truck but I remember we changed out the fuse box and it fixed it.

Unplug the fuel pressure sensor and the 7th injector fuel pressure sensor on the fuel shutoff valve block and see if thats were the fuel is seeping in from. Usually its oil in the engine ECM connectors from oil pressure sensor, the oil level sensor or the piston cooling oil pressure sensor. I bet 75-80 % of the MP engines that are 2 years or older that come through our shop have oil in the ECM connectors. Just the nature of the beast. When under warranty, we replace the sensor and harness. At one point we had enough engine wiring harnesses to fill the bed of a pick up to the top. Took them to the copper recycler.

One of the makers for the DPF delete kits for pickup truck sized engines is being sued by the EPA for I think around 230 million dollars. At one of my last Mack classes I went to we talked about the DOT having a reader to hook up to the NOX sensor and see if things are working correctly. Also check this link out. http://www.mycarlady.com/2010/09/17/epa-fines-dpf-delete-users/

yes the big Borg Warner cool logic fan clutches seem to fail often. They updated the part # but I dont know if they actually improved it any.

Hope this helps. Heard there now is a non-wastegated turbo for use on 460 hp ETECH CCRS engines. The CCRS engine came out around 2002 till 2004 when the ASET series came out. IF you wanted a 460 HP during this time, it came with a wategated turbo. On this engine the ECM closely watches the boost/turbo pressure. If too much boost (driver screwing with the wategate adjustment) the engine will derate and malfunction light will come on . If too low boost the malfunction light will come on as well. When we do HP conversions on this series engines we usually only go up to the 427 HP cause the wategated turbo is so $$$$$ and ongoing problems with the wategate. However our other store says there is now a non wastegated turbo that is approved for the CCRS 460HP but I confirm that for sure. sb221029.pdf

I assume its an air fan clutch? If so check fuse # 41 ( i think) in the fuse box in the middle of the firewall under the hood. This fuse powers the fan clutch circuit. Also check the A/C high pressure switch, if its a open circuit it will keep fan on all the time.

Heres some info on the pump. We always replace them as a set or they will leak fuel. PV729 -FSB233-004_M.pdf

Not so much on the older engines it seems. Our boss has been experimenting with fuel filters brands and part# s on the MP engines and has found out some intresting stuff! On the older trucks with the Davco fuel filter/ plastic upside down bowl style fuel filter system, there is alot of different micron rating filter that we didnt know about.

Make sure your primary fuel filter is a Mack brand filter. Many other filters may say they fit but the Micron rating might be to small and since the primary filter is on the suction side its hard to suck through 5, 7 or 10 micron when it should be and 25 or 30. But its easy on the secondary side where you are pushing fuel through a 5 micron filter. We had problem with a customer who liked to use balwin filters on his truck and it would have low power/ fuel pressure only with a loaded trailer.

I take it that in injectors have never been out? I know of only 1 2008-2009 MP engine in our area that still has the orignal copper cups/injector holders in it, most were replaced once with the original style copper the again with the new conical stainless cups and injectors. Some would be hard to start after setting and some would set low fuel pressure codes only after getting warmed up. We say many weird things caused by compression in the fuel system from a leaking injector cup.

Have you replaced the fuel pressure regulator on the left side front of head? The new style should have 2 knoches on it. Check the fuel lines and blow out the ECM cooler plate fuel galley and check the fuel line coming out of the ECM cooler plate as it goes into the back of the filter stand , it seems to plug at the filter stand banjo fitting. If black rubbery snot looking stuff is found , add asphaltteen ( spelling???) fuel treatment made by Fleetguard, its the only thing that will clean this stuff out. If still no luck I would pull the injectors and checked for cracked cups or injectors. If its been changed to stainless cup already check for hairline cracks in injector body. The stainless cups dont give like the copper ones and cracks the injector.

Oil temps seem to run alttle warm in the MP8's ( compared to the older Mack engines) which is normal. The coolant temp should be around 190(F) with 210 in a hard pull in the summer heat. We replaced alot of water/coolant pumps and fan clutches on these engines. We replaced 2 Cool Logic electronic fan clutches on the same 2012 CHU 505 in 3 months. Water pumps seem to fail around 200 -300 thousand miles.

As Staxx said, the #1 (front head) engine brake solenoid is the bad. You could pull the front valve cover and check the power (valve cover pass through) wire end and the ground wire end and make sure they didnt break off , which is a common occurance. If that is the case you could crimp on and new wire end and test drive.