Having trouble with this one. Will only go to 2000 rpm's and has a miss in it. Any clue where to look?
Is the PTO switch accidentally left on?
Thanks, allready checked that.
Well, if it ain't that, then your check engine lamp is on and you're sporting a code for an injector fault
Can the pto switch go bad?
Did change the one injector that I thougt was bad, will check again on others.
Not the injector itself... FICM has 8 injector driver circuits. 1 circuit per injector. #7 and #2 connector at their respective injector, have strain in their routing, and the resulting side load on the connector causes premature terminal tension loss. GM & the aftermarket both offer pigtails and strain relief brackets to repair the #7 & #2 connectors. The rub is, the software/ hardware designers made it so that when a single injector circuit is open or shorted, the FICM disables FOUR injector circuits. Now, I'd be getting the codes out of the ECM before proceeding, because a low rail pressure code can cause similar issues, but, there is typically no miss or engine shake.
Check your harness over the top of the engine. Mine has done the same thing. I mistakenly went through 2 injectors (back passenger corner #?? as I'm an inline mech) and finally was jerking around on wiring and it cleared out. Started it again recently and found a few wires rubbed through under the air filter in the main crossover bundle. These trucks ride like bricks and my fuel shop owner tells me the harnesses are the main problems with them. Good luck! It will be my last GM product for a while!
Seriously? My 4500s have taken more abuse and given tremendously less trouble than my f450 crap. As for the harnesses being a problem, bah! I say. That year and newer all use the same injector, and, in a fleet of over 30, I've only ever changed one injector, and that was for a balance rate out of spec, at over 300k miles. Apparently, you and your tech aren't as hip to the duramax motors as I and many, many others are. To the OP, again, get the fault codes and report back...my money is on a P0207 with a P2149. Next, you two are gonna ask how to convert the 5spd allison to a 6spd, without tearing down the transmission.
In hindsight, I may have been a little blunt, but, I get frustrated when I see someone shotgunning parts at a duramax, or, not even getting fault codes read to aid in diagnosis. I use a $17 bluetooth dongle with the free Torque app on my cell phone. But, that setup, unfortunately, wont read abs or airbag codes...but, $17, it has long since paid for itself to read engine and transmission codes.
OR maybe there's more to a truck than the engine
I ran a 5500 for a few years (dealer I worked for had about a dozen of them). They had a fair amount of issues with injector harnesses rubbing through as well. Happened twice on mine alone in the span of about 6 months. I attribute many of the truck problems we had to the abuse they got running around the mines.
heymcall; you and your type are the reason I'm now a lurker on this site! I got tired of offering advice that has worked for me and getting told to sit down and shut up by someone who 'knows better than me'! No I don't run a fleet of them. My advice was based on problems I've had with my truck at 260K miles. I've had a turbo clamp band break which can't be had without buying a turbo kit, the transmission slam down to first at 65 mph because of loose harness connections, their sh!ty leaking filter setup and a host of other problems. The GM cut was from many other problems from other GM products we've owned as a family since the '50's. I didn't shotgun parts at mine. It was diagnosed by my friend at his fuel shop with a pro scanner and it showed a failing injector! I also have one of the bluetooth readers and TorquePro app plugged into mine to deal with codes (engine and transmission) constantly popping up. As for the harness rub, maybe I should have taken a pic of it so I could prove to people like you that it does happen! I had to splice wires and re wrap the harness and the code and miss went away. I got onto this site for advice and as I have gained experience try to pass on what I have learned as others have done for me. No more. I'll just sit back and let someone flounder with a problem that I have personally dealt with and could offer advice on. This reminds me of when I was told I was a liar about a dozer blade angle cylinder piston bolt being ripped out from corner overloading when I had to replace the cylinder for it. So much for this being a site where we can share knowledge experience and ideas dealing with our industry!
"Me and my type"? Bwahahaha. Two injectors before finding a wiring issue? Sounds expensive and frustrating. The original poster comes across as someone who has little Duramax experience, and he described the classic injector connector issue that plagues the 2005 and some 2006 LLY motors. But, the solution is out there. And, I wasn't discounting your harness rub suggestion, but, it certainly isnt the first thing to look at. Perhaps you are aware of the harness rub issue (well documented) where the FICM harness is tied to the alternator bracket. But, again, I'd still start with, at, the #7 injector connector.
You 2 girls should hug this out. Just make sure you both wear your bikinis and are lying in a tub full of jello. Everyone has different experiences with similar issues, ALL should be welcome.