steeler

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.

Ya I always try the regen first, sometimes it works for me and sometimes not.

The code won't go inactive until it goes thru it's checks with the 5mph derate temporarily removed. Drive it like that for 30 minutes or so and it will either clear out or tell you it's going to derate again.

Ok last update.....it always amazes me how you never seem to get the WHOLE story from the customer. Anyway, now I'm told the engine (other than the injection pump) is from a different truck. Engine is a 1994, truck is a 1997. So I'm told they took an engine from a vmac1 truck and just swapped the injection pump. This might not be an issue, I'm not sure if there are any major differences there. Either way it doesn't matter, customer picked the truck up and is going to run it till fall, then pull the transmission and check the flywheel. Thanks for everyone's help!

Ok after going thru it all again, I can disregard that 33 fault code. I was using a pro link and had the vmac1 cartridge in it. I hooked up the laptop and it's actually a 32, for the rpm sensor. I've eliminated the wiring and sensor, so I believe they have the wrong flywheel in it. I don't know who was working on it before but damn, let's just say he was a hack. Sad thing is, I'll probably never know what the outcome is. The only reason it's at my shop is because nobody else could figure it out, so the customer is going to pull the flywheel out himself.

Hmm. Interesting. Ya everything I'm looking at other than the module screams vmac 1. But I checked the vin and it is coming up as vmac2. The pump part number is correct. I got more info on this truck. I noticed it has a new clutch and flywheel somebody else put in. I'm now suspecting they may have the wrong flywheel and the rpm sensor is not reading it. The engine will die if I unplug the tem at the pump, but runs the same with the rpm sensor unplugged. That tells me I've got something fishy going on with the rpm sensor. It's supposed to ohm at 200-300, but I've got 180. It's a PAI sensor, I'm going to put a Mack sensor in it and see what happens.

Thanks pro. I'm not with the truck right now but I do know there is a bulkhead harness going into the firewall on the passenger side. I remember that was how I could always tell a 1 from 2, but I couldn't remember which was which. So, sounds like a 1, so why does my module have a vmac 2 sticker on it? Didn't the 1s have an fic module?

No, it won't damage anything at all. It's just annoying.

Yup sure sounds like resonant ride. Unfortunately I'm not sure there's much you can do to fix it. We've sent pumps out before, some were better, most weren't. I'll do some digging about that contraption Mack came out with. Maybe someone else here knows of a fix?

Yes, resonant ride in the pump feels kinda like the fuel rack in the pump is bouncing back and forth, usually right around that rpm. I remember it being a big pain in the ass in the early/mid 90s at the dealership I worked at. Sent out many pumps for this problem, but rarely was it ever fixed. I remember Mack coming out with some kind of contraption that mounted to the front of the pump to fix it, but man its been a long time! Does yours almost feel like you are bouncing the throttle real fast at that rpm? And usually if the engine had a strain on it, you wouldn't feel it. Only happens when there is steady rpm with little to no strain on the engine.