Dalton1

Found a broken wire in about 2' down the harness from the back, no idea why, no damage to the wire wrap or any other wires.

I'm working on a 09 GU713 that has no left rear turn signal. Everything else works fine, so far I've un hooked the wiring where the factory wiring goes to the dump body, has about 1v coming out of the harness at the rear of the truck. Truck had no turn signals at first but replaced the turn signal switch and updated the flasher per the service bulletin from Mack, that fixed everything but the left rear blinker. Haven't been able to find any wires damaged. Is there any common spots to look for on these? Does anyone have a wiring diagram for the lighting circuit? Thanks!

McFarland spring is still across the street, they usually seem pretty busy. Doesn't sound familiar but I'll ask about him next time I'm up there.

It's not old to me either, newest truck I've ever owned, I bought because I wanted the newest truck I could get with a true Mack engine. They work on them but last time I was there they only had one guy that knew anything at all about the grey engines. I think the pump shop your talking about was converted to the Hino sales office unfortunately.

I wish you were still working there!! I just pulled the nozzle, visual looked ok, swapped it with #5 and the problem moved to #5 so I guess I got a bad nozzle, thought I'd get more than 40 miles out of it.

I'm doing the work myself, I usually do everything but this one is challenging me. There's just O'Connors in Portland but from what I understand the don't do much with the old mack engines like mine anymore. I don't know anyone local that works on them.

Oil level doesn't seem to be rising but it hasn't run much either, just a few minutes. I'll pull the nozzle in the morning.

I'll give that a shot next, there's no smoke at all so I wouldn't think it would be a Cracked or failed nozzle. Here's that video if it's any help https://youtube.com/shorts/fkKcnWAUbiw?feature=share

Finally got the ecu swapped out, made no change unfortunately. When I cracked the #6 cylinder injector line it is a fairly steady flow of fuel and seems very aerated. Even makes small bubbles, no matter how much I bleed it. Any other ideas? as I said previously it does this same thing with a known good EUP. Any chance the nozzle could cause this somehow? I don't see how but they are new so it's possible I got a bad one or installed it incorrectly. I took a video of the way the fuel comes out but not sure how to upload it, I'll work on that.

Thanks everyone, I will try that next and update with results.

Maybe I'll give that a shot next. I find it odd my scanner won't preform cylinder deactivation tests on any cylinder, always work before on that truck, makes me think there might be an issue in the ECU. I did check the lobe and lifter both look perfect.

There's no smoke at all, the valve train appears to be ok and is in adjustment. Engine brake still works high and low so I don't think that stuck on. No rag in the intake but I would have been happy to find one! Tried swap wires on eup and cleaned ecu connectors with no change. I have access to a twin truck, would it be worth swapping the ecu? Or would it not communicate properly?

I did swap out the 5 and 6 injector, problem stayed with cylinder 6, I'll clean up the pins on the ecu and connector, is there a best way to do that? Electrical contact cleaner? Thank you for the help, that page out of the manual is helpful.

I'll give it a shot, yes valve were done by the book, problem came on very suddenly. Like that cylinder just shut off.

Pins aren't perfect but don't look to corroded, they have dielectric grease on them.