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Mackpro

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Posts posted by Mackpro

  1. On the early ones that sat on top of the dash we had lots of them get zapped when jump starting. The later ones mounted on the RH side of dash seemed better. We still lots of both that don't work. Matter of fact , I haven't seen one of the early ones that still works in about 10 years

  2. We see lots of split aftercoolers on GU and  CHU's. Usually  the bottom tube is blown out. Pull up your boost guage on your GuardDog display and see what your boost is under are a hard pull. Should be at least low to mid 30's and as high as 42.  A sticky VGT turbo, a bad boost pressure sensor or a problem with your EGR valve/ flow sensor can cause poor MPG. My buddies 505 plus CHU with 3.21 gears more or less idles down the interstate at 1250 rpm. He gets in the 7 mpg range and the day I rode with him , he Grossed at almost 99,000 pounds. From what I have seen in the last few years , it's all in the rear gears.  The MP 8 engines have the power to to run the high gears now.  A logging customs here has a 505E CHU with low rears gears for use in the mud and woods. The paper mill here closed a year ago so now hes hauling different products and mostly interstate. The 1700+ rpm is killing his mpg.  I think 5.2 was his overall and 5.7 in cruise. Gotta get thoses RPM down

    • Like 2
  3. Engine ECM's should be the same.  ECM location  and engine harness could be different as the 2001 might be the LSR ( Left Side Redesign)  where the engine ECM is mounted on the left side of engine up high on the intake manifold. The 1999 should have the ECM mounted down low on the right hand side.  You gotta watch as some time in 2002 the CCRS  ETECH came out and used different ECM part # and EUP's and injectors were different.  However they looked almost the same.  I have seen 2002's that have the early ETECH and some that had the CCRS engine.  We gotta 1999 CL in the shop now that someone put CCRS cylinder heads on  and now  getting fuel in the coolant. The CCRS heads have no fuel return passages because the CCRS injectors dont return fuenl.  By using  the ETECH injectors  in the CCRS heads the return fuel has no place to go except past the injector cups into the coolant passages. Just because they look the same dont mean it will work. 

    • Like 1
  4. Disregard my post. I see now you have a CXU/CHU. Totally different. I must have been drinking that day! Lol. Have you had the fuse box recall done?? Water was getting in the fuse panel down by the clutch pedal and causing lots of issues 

  5.  

    Around here , a AI-400 is a little weak for a tri-axle dump. 427  would be minimum but you can skyways bump it to 427/460 later. First look for frame rail cracks around steering boxes  on both sides. Being a 2007 it might have the reinforcement plates already installed. 4.42 or 4.64 gears work best with 24.5 full size tires. If truck has 3.73 or 4.17 gears and your planning on going to tall 24.5's forget it it will mostly always be weak. Take it to a dealer and get the valves adjusted and rocker arm hold down bolts replaced, bolts are prone to failure and usually cause a $5000+ cam job. While there get all software updates in both ecm's updated to latest levels. ( VECU to step 15b).  Expect 5.3 mpg on your best days  it's the norm. Lots of my friends run AI's hard and have little problems and they have 500 to 750,000 miles on them. Just remember it's not a 13, 15 or 16 liter engine, hell i don't think it's really 12 liter as Mack say it is (11. Something liter) . Just don't think is gonna pull like a monster cranked up cat or Cummins. The early  Mack ETECH and CCRS engine (99-03)  had better torque and HP curves and were more forgiving on tire size and gear ratios.  But thanks to the EPA in 2004 we got the AI  (and AC  in the Cx/Cxn /CH /CHN trucks)  engine . The AI is a good engine that at least doesn't have a EGR valve and cooler on it to worry about. 

  6. Sadly all our old Pro Link stuff wore out and we now use  the Mack Tech Tool/VCADS  program  on VMAC 1 and VMAC 2 and its horrible to navigate and do anything.  Excluding our wrecker , we only work on 1 or 2 of the older VMAC's  a year. The Pro Link stuff if you can still get it is the best. 

  7. Lost comms on the J1939 wires  ( always yellow/green twisted wires) between the engine ECM  ( EECU)and the Vehicle ECM (VECU) .   Fist pull the 2 connectors off the engine ECM and check  for antifreeze in the connectors/ EECU.   If OK pull the kick panel in front of the passenger seat and look for rubbed wires  coming out of the VECU and rubbing on the kick panel, is a common problem. However normally if the J 1939 wires go down the engine will die if you shut the key off but it takes about 10 seconds. When the J1939 high speed data line  goes down the low speed J1587 line takes over but every thing works slow. 

  8. On 3/5/2017 at 7:29 AM, jmb4wd said:

    I have a 04 AI-375 that does same thing.  Right when it goes to full torque it cuts back to 70% for 5 maybe 10 seconds and then turns loose again.   Replaced one unit pump and injector that had multiple faults.  Not as bad but still does it.  Been in shop multiple times but no success yet finding problem.  

    We just had CV in the shop doing the same thing.  The throttle pedal wires at the VECU are shorting out on the kick panel in front of the passenger seat , Pull down the black kick panel, 4 screws on top and 2 at bottom  at the floor. Lay the panel down look very closely to all the wiring and how they lay and contact the panel. You will probably see rub marks on the panel where the wires come out of the VECU and ABS  ECM and loop back to towards the fuse panel.  Repair wires if bare copper is visible . Tape up all wires where hopefully they wont rub and short out again. We have seen this many many times. And will not set a fault code most times. 

  9. We just did a total rebuild of our 1994 CH wrecker. Reman Mack 454 engine, injection pump and starter , water pump , clutch , new engine harness and on and on. We replaced everything from the trans forward even the radiator and after cooler .  Every thing straight from Mack .  Only thing we couldn't get was the ABS harness , however we ordered the ends from WABCO and built them ourselves. Cab parts however might be a different story. However we did replace the heater core and evaporator core as well. 1999 and up ETECH  and CX/CH style trucks  your mostly safe .

    • Like 1
  10. Those sensors do just go bad over many years. Replace it and make sure you use the same shims as the old one.  We used to add an extra .015 " shim  on the older trucks due to camshaft endplay.  If problem still happens  and its causes a miss/vibration  and you have a older ETECH and with the small vibration damper, We in the past have installed the bigger damper and it solved the issue. But first I'd just replace the sensor. 

  11. I will say, this is one of the best pulling trucks I have ever road in or drove. The owner picked me up and we took a load of corn to the grainery last friday.  Grossed out at almost 98,000 pounds and bad injectors we had no problems in the hills or in heavy traffic.  I thought it was awesome but he said it was no where as good as it usually is. Truck is a CHU daycab  with a 505 PLUS MP-8, T-310 trans , Meritor rears with 3.21 gears and disc brakes all the way around. Running super singles  on the back 445/50 R22.5 .  No speed limiting and he dont baby it at all and still getting 6.1 MPG on his trips.   I have pulled up some of his other longer and lighter trips and they were in the very high 7's . 

  12. I wonder if the Tech is using VCADS/ TechTool  or the old VMACIII program to change parameters?   We only use VCADS/Techtool on the VMACI, VMAC II and the MP engines.  on the ETECH, CCRS and ASET engine we use the old VMAC program wecause its so much faster and easier. 

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