I recently bought a 2005 3500 4x4 with the 5.9l. it gets great milage and doesn't have any probles starting up. 4x4 works great, it has 143,000mi on it and just had a new transmission put in it less than 1000mi ago along with new tires. The guy had sold it for his son who left for vet school and said his son did all of the maintenance on time and becuase it was so clean and everyrthing including all of the fluids checked out that I could see, I bought it for 16k and thought i got a good deal on it.

I noticed a few days after buying it that if i rev the rpms up, it will temporarily hang, followed by staggering back to its idling rpm range. I have never owned a diesel before and i wasn't sure if this was a unique quality to expect out of a diesel.

I took it to Truck Stop Performance in San Antonio, and they told me that because it hangs like it does, i am gonna need new injectors. the previous owner had given me a quadzilla stealth tuner that he said his son had used for better fuel economy. It wasn't modified in any other way, other than a K&N and so i didn't have any particualr reason to think he was using it for pulls or goofing off. The mechanic said that they can be particularly hard on the high pressure common rail and that it likely damaged the injectors and i need to get them along with an airdog.

It runs fin never stalls, no smoke, no hard starts, but i fear that i might have bought a truck with an expensive problem. should I take it to a dealer? is there any specific diagnostics to check out if it's just one particular injector? please give me peace of mind.

 

I think,and its just my opiniopn,it hangs after reving up because its burning off stored preasure in the injector pump,if that makes sence to ya.Mine will stay reved for a second after i hammer the throttle and let off it.The pump is makeing all that preasure,after u let off the go pedel the preasure made has to go someplace.

 

Diesel burns slower than gas does, hence that brief hanging RPM and slow return to idle after getting off the throttle. This throws alot of gas guys for a loop when they first get into a diesel.

Doesn't sound like you have anything out of the norm....unless it is really bad.

Hope for your sake your injectors are fine...****s not cheap.

 

Diesel truck rotating masses are also a LOT higher than gas engines - they're slower to rev (with equal power applied) and slower to slow down. The reason you don't really notice it on the rev-up is that you've got 600+ lb-ft of torque ripping it up to speed. Diesels also don't have throttle bodies that close. In a gas engine, you close the throttle and the cylinders create a vacuum in the manifold that slows the engine down. In a diesel, there's no throttle, no vacuum created - which is why diesels don't engine-brake very well without an exhaust brake.

I'm not saying you don't have a leaky injector, but if it drives fine and you don't feel the fuel economy is horrible, and you don't have hard start/stop issues or abnormal smoking, then I would suggest you probably don't have a problem.

If you DO have an injector problem, buy your own injectors online somewhere.
Dynomite Diesel stock injector: $450 each
moparonlineparts.com: $442 each
MSRP: $640, but hope there's no matrix


Interesting. MSRP on the 6.7 injector is over $1200.

 

Sounds fairly normal to me. Diesels do work differently than gasoline engines and you have to understand how they work to really understand the problems they have when they do have problems. If it were an injector issue, you would see it in the fuel efficiency and the power. When you are hammering the throttle and it hangs are you in park or neutral? If so it is just the engine burning off the unused fuel and slowing the motor down. If it were injector problems your CE light would come on. If it's running good and not using a $#!t ton of fuel, you're good. Like I always say to people I work with, If it ain't broken don't fix it or you might just break it. Also, thank God that they never put Caterpillar engines in our trucks. An injector for just a little C7 can be 2500 bucks.

 

My bosses truck went in for a bad injector. Dealer wanted $973 a piece for injectors for his 5.9

 

I've been told that the later commong rails, starting at 04.5 had some injector issues, friend of mine has an 06 and he had an ijector fail and he had a blue cloud of smoke behind him for about 300 miles before he got home. Another examoke I almost bought an 05 for my next truck it was really good shape but had an injector fail and it melted a piston.

My experience has been if there is no smoke an injector should't be the first place to look, especially if its starting good, ect.

The airdog can be justified the tuner is going to dump more fuel in the trucka and the factory ones cant do the work without failing quicker. My dads 04 had the lift pump go out at 65k and he hasn't done a thing to the truck except a 5th wheel hitch and a little chrome.

It depends on what your doing with the truck, just driving you may not need the pump even with the tuner, but if you have a bad left foot like I do then you should probably get one. IMO

 

That's the matrix....

That's so they can charge Joe Blow more than they charge Bill's Repair Shop, but still make decent coin off Bill... It makes Bill happy knowing he's getting a "deal" and that his customer will think he's getting a deal if he calls for a quote from the dealer.

Or something like that, that's how it was explained to me.

 

if you do have to replace the injectors you could replace them with some industrial injection ones

 

I bought a 04 dodge about a year ago with the same problem as you have with the rpms hanging for longer than normal. My injectors ended up being bad, I ended up buying 50hp injectors cheaper than stock injectors and put them in myself. Not real hard to do except number six is kinda a pain. But a good way to tell if they are going bad is to check your engine oil after you been driving it. Mine was leaking fuel into the oil, so just ckeck to see if your gaining oil on your dipstick.