steeler

No codes. What I do with these is put a pressure tester on the coolant tank, fire it up and watch to see if the pressure builds. This one instantly started climbing, normally I don't see much pressure building until the coolant temp starts to come up. At an idle the pressure steadily climbed to 10 psi in about 3 minutes. If I ran the rpms up it would build pressure even faster. I've only seen this on an mp7 one other time which ended up being pitting in the head where the injector cup seats, letting compression into the cooling system. As far as the egr cooler, am I correct that there wouldn't even be 10 psi of pressure there at an idle? I know that it isn't leaking coolant anyway.

All of the above advise applies here also. Very well could be that the harness is pinched between valve cover and oil valve, or bad terminals at injector. Figure out which cylinder is the culprit first. As far as the new harnesses having the high tension terminals, I've ran into both 04 and 07 emission new harnesses that do not have the new terminals. The last harness I changed out, I replaced the terminals before I put it on the engine. (After I confirmed it didn't have the good ones)

Common issue there, more than likely sliding clutch and gear are worn. I probably do 10 or more a year. While you at it, might as well change the syncro as well.

No sir. Trying to finish up a couple other projects first. Still trying to decide where to start. Pulling out cups? Pulling head? I checked the buildup of pressure with the air compressor pumping, and with it kicked out and there was no change, so I think I can rule that out.

I don't think so in this case, it will build up to 10lbs of pressure just idling for about 3 minutes. Faster if it's idled up.

2009 mp7, what are you guys seeing as the most likely culprit for building pressure in the cooling system? This one is building quickly, literally spraying out of the overflow cap. I know I'm probably looking at either head/gasket, injector cup or air compressor. Trying to decide which row to take here.

I might just have to grab a can of that, thanks.

That's what I normally do on other applications, but this one has the ports making a 90 degree turn down inside the hole so I can't get anything to eat thru it. I tried carb cleaner which I've had luck with in the past, but it didn't help. I just put it back together and told the customer that he will have to deal with the yellow light until the part comes in. We ordered it as unit down, which usually speeds up the process. Hopefully it won't take a month.

Exactly. I can't get anything in there to break it loose.

I sent you a message cmac.

These things are in back order till November. I've got one clogged badly. Any tricks? It looks like it can be taken apart, but I don't want to kill the truck.

Sorry for the delay, crazy busy lately. I'll get that for you tomorrow! Hopefully I can find it.

I know this is a little old, but have you fixed it? I assume the engine is an "AC" engine? If so I have a diagram at the shop I can send you.

I agree with what these guys are telling you regarding the heater shutoff valve. Start with that. Also, did you charge the system with the correct amount of refrigerant? If it is overcharged the higher rpm's can raise pressures too high reducing cooling.

I don't think I've ever successfully fixed one with just the kit, but have fixed many with kit and lines. Do both. Make sure you have the new style oil feed screws, and remove the little ball and spring from the bottom. The kits usually had instructions in there.

We usually start with a rebuild kit and oil lines. Can you even get the rebuild kit anymore? I thought I heard they were no longer available, but I could be wrong there.

Be careful messing with the gov. The rule of thumb I always used when bumping them up was to screw the star wheel as far forward as it will go, then slide the plate forward about the thickness of a dime. That will make them pull stronger and dump more fuel sooner, without waiting for the boost to build. I've never messed with the springs though.

Well I found the problem. Pin 16 on the control panel is a ground, I was getting just enough of a ground to operate everything but the compressor. So after running a new ground I have good power to the compressor, but the clutch is toast. Oh well at least it'll be working tomorrow!

It shows that as separate. It has a separate pressure switch that sends is signal to the ecu for the fan. Didn't have a chance to work on It today, probably in the morning.

Should have mentioned that I replaced the condenser due to a leak. I've also tried a new control panel and new temp sensor as well. I don't have any fuses or relays that are labeled specifically for the compressor. There are a couple others that are marked HVAC, but they are powered and good. I did find a different diagram than the one I was using, it's showing power to the compressor coming directly from the control panel, unfused. I'll check for continuity on that circuit in the morning.

2014 GU713, I've got no power to the ac compressor. My wiring diagram is a bit outdated so I'm not sure I'm going in the right direction. My diagram says fuse 53 is for the compressor, but the sheet in the fuse panel shows 53 as a spare. There was no fuse in it, and three is no power to it, even though it is pinned. So does anyone know where the power comes from? I know it goes to the pressure switch, I have continuity from switch to compressor, but no power. Thanks for any help guys.

Good deal. Glad you found the problem!

Did you check the fittings at the ecu cooler plate? They are notorious for catching debris.

Ya this is a tough one without laying hands on it. Sounds like ecu is losing power. Do you have a diagram?

Kinda off topic here but we do quite a bit of work on paccar engines. You wanna talk about an SCR nightmare, wow. I had one with a def quality fault that just would not clear. I threw everything under the sun at it, nox sensors, def doser, new def fluid, dpf filter, catalyst, 7th injector, countless hours of troubleshooting and test driving all to no avail. Ended up opening a case with paccar engineers and after several regens and 2 40 mile test drives that had to be recorded and send to them, they simply gave me 24 hour special access to a feature in the software that allowed me to clear the code out. I mean really? After all that, it was that easy? I wish they'd give me that special button permanently! The truck worked fine after that for about a year, then the same crap started again. The customer said screw it and had it deleted, and I don't blame em.