tbone1983

Does anyone have a wiring diagram? I am looking for the pinout for the ecm also. Is there a wire from the battery with a fuse that powers just the ecm like a cat?

When doing the tune sometimes the type of fan gets changed in the programming. There are 3 types. Viscous, air, and electro- viscous. What type do you have? If the computer is programmed wrong it will not turn the fan on. Does your fan work?

Get the adjuster collar to stick depressed, start it up and drop the clutch. Be careful it can destroy the clutch. I have had good luck with this.

I forgot to mention the truck would also randomly high idle. Like max out 2k rpm. Only way to get it to stop was to tirn it off. I thought this was strange also. I have a feeling it is all related to the computer or some emission related non sense. I could really use some good input.

Have a 2008 mack mp8 that will randomly turn off. Sometimes it will restart other times not. On the last time it would not restart the dash cluster would turn on but the hour meter would just have dashes. When I tried to retrieve the codes in the dash there were just dashes. Like it was not registering the ECM. The lightning bolt was on and the truck would not crank. It was like the computer would not send the signal to tell it to crank. Started it today fired right up. Ran it for a bit than it shuddered and turned off. Restarted with no issues. It has an intermittent VGT turbo code. And the turbo will not spool while sitting idling. We replaced the actuator and it seemed to fix it for a few weeks but now it is back. I'm leaning towards a sticking turbo but in VCADS there is no excessive force on the turbo actuator and it reads normal. When it is acting like this it will not regen. I have a replacement turbo for it but I'm more worried about the computer. When it tries to cycle the vanes while idling it will start to miss then clear up when it is not trying to adj the vanes. Lightning bolt off and on during this. Has anyone had one randomly turn off and occasionally not restart? Any place I should be looking before we replace the computer? We have 4 of these gu's and have nothing but emission problems with them but the older RD's just keep going. Unfortunately no one wants to drive the older trucks.... I'm a little desperate for some help on this one because I have another that is going to have to come in for an EGR issue this week.

I am desperate for help. It started with a failed power steering pump and am finishing up with an air problem. I ended up putting a new compressor on. The truck had a midland on it and all I could get was a bendix. The problem I have is there is a quick release that is leaking air. I replaced it thinking there might be some dirt holding it up but that didn't work. The truck wil not build any air at all. It seems like it is somehow related to the foot valve. When I press it the sound of leaking air changes. The line right off the compressor feeds one side of the quick release. I think the top line of the qr goes to the foot valve and the othere side I haven't traced. I know I didn't do a very good job explaining what is wrong but this truck has me exhausted. I can't beleive the luck I have had. The only thing that changed in the air system was the compressor... So I am at a loss. The truck is a 1987 rd 686s with an e6 and a 6 speed. It is a tri axle dump truck if that makes a difference. I really need a guru here I have to go to work monday. I have already lost 2 days dealing with a brand new defective power steering pump.