Bad Injector-Can I drive it.

[nwjetboat]

Just got the truck back from the dealer. #5 injector is bad. I took it in because of a knock at just above idle, (900-1100). The injector is on backorder, so I asked the service writer if it was O. K. to drive. His reply was "I guess so,shouldn't hurt anything. "

To those with more experience than I have with these motors, Will using it harm the engine?

 

[Prairie Dog]

It won't hurt anything if it's not delivering fuel. Of it's stuck open it will quickly burn a hole in the piston.

 

[jjdiesel]

nwjetboat, I had the same problem, had the same question. I have a long-standing relationship with my service manager as well as the diesel tech. Their explanation was..... as soon as you come off idle (when injector knocks) the rpm's of course rise and the combustion pressure in the cylinder evens out. The injector likely operates as its supposed to under the different operating parameters, just not when its at idle or just above. That's why it seems to run fine as soon as you get going. Anyway, it probably won't hurt a thing to drive it..... I drove mine for a couple weeks at least before getting it changed out, you should be fine Hope this helps a little.

 

[Johnstra]

Hey guys. Can those of you that are experiencing these injector problems describe the knock you hear a little better? I have a subtle knock that I can hear coming off idle only when the engine is good and hot - like after I've been driving for 30-40 minutes. I don't hear it at all when when the engine's cold. It's not too loud, but it is noticeable and it sounds like whatever it is is related to a single cylinder. And it's a new sound, not something I've heard before. Just started hearing it in the last week so I'm trying to decide whether I want to take it in to the dealer. I should mention that I am running on my second tank with 'Howe's Meaner Cleaner' additive in it. I don't normally use a fuel additive, but I wanted to give this stuff a try. I put 4 oz in with my last fill up.

Thanks,

-john

 

[jwilliams3]

Dont drive it.



--Justin

 

[nwjetboat]

Johnstra, Sounds like you have the same problem I have. You could only hear the knock after the engine was good and hot, and it is most pronounced at 900-1100rpm. If you had the window down, and pulled away from a light you would hear it. Sounds just like the 2002 and before motors, only on one cylinder.

If I put it in neutral, the sound diminishes. Another issue, that may be related, is the oil was unusually black when I checked it. I was not above full, just blacker than normal, so I changed it when I got home from the dealer. I'm not going to drive it.

 

[rholcom2]

I have a friend with a P-Stroke (I know I know), but he had a bad injector, took it to the dealership. The Tech, said "Bring it back tomorrow and we will slap a new injector in it". He left the parkinglot, and got about 6 miles down the road, and a nice big rod went through the pan. I guess there is enough compression to suck the oil past the rings and burn it. Didnt take too long to burn up all the oil in the motor. When it quit, there was only about a gallon in it.



Dont know if this crosses over to the Cummins, but that was his experience.

 

[Johnstra]

Cr*p! Well, I just talked to my service manager and I'll bring it in tomorrow so he can have a listen and use the scan tool to isolate which injector it is. I told him I hate to drive it as it is and he said it's standard that he tells customers to go ahead and drive on a bad injector since it "normally" won't hurt anything. I told him that's true unless the injector sticks open... He says he's never heard of one doing that, so I kindly informed him that he could read all about it on TDR. I have no choice but to drive it, though, so I'll keep my fingers crossed.

-john

 

[rbattelle]

I have a knock that comes and goes. It will gradually get really really bad (sounds like a monkey under the hood hitting the block with a claw hammer), then suddenly after a couple months it will disappear completely. Only does it when the engine is hot, and pretty much only just off idle to about 1100 RPM.



I mentioned it to my dealer once, and he said "it's normal, they all do it". My attitude is this: I refuse to take it to my dealer and let him go crawling all over my engine compartment chasing down a mystery noise and screwing things up as he goes along. And I refuse to let them open the fuel system unless there's a clear failure. I have 29500 miles now. If the engine explodes, Dodge has to give me a new one until I hit 100,000 miles. So I just drive it and be happy. No oil consumption, normal fuel consumption, normal power.

 

[boonsur]

I'm still wondering if it isn't the pilot injection turning on & off. I'm pretty sure the 305's have conditions where this happens (loaded, A/C, etc. ). Don't know about the 600's. I am somewhat assured by the fact the problem goes away after a brief shutdown, or sometimes by shutting off the A/C (parameters resetting themselves).

 

[FPoitra]

I had the same exact problem last month except that they replaced 2 injectors on my 04'. Make sure they perform a pressure test on all injectors. On mine, 1 failed at high pressure and the other failed at low pressure. It is not that they go "bad", it is just that they do not test to factory specs meaning they still function properly. I was worried about driving mine as well, but it is the only vehicle I had and put around 1000 miles on it with two bad injectors and nothing seemed to happen at all. They told me they were on backorder but I got them in 2 weeks. My advice would be to drive it easy with no pulling. After they installed the new injectors, it was as good as new, no more annoying injector knock. (knock on wood). Hopefully DC will look into this situation real soon! I know how you feel, but take it easy and when they get the new injector installed, your problems should be solved.

 

[Johnstra]

I took mine in to have to listened to. The service manager used the scan tool to kill each injector. I just set the e-brake, put it in 1st and loaded the engine a little. It was obvious that injector #1 was making the noise. We walked through and disabled each injector one by one just to make sure. With injector #1 turned on - knock, knock, knock, knock. With injector #1 turned off - no knockin'. Whole process took about 5 minutes. He's ordering the injector today.

-john

 

[rbattelle]

John,



There have been lots of instances of slightly loose injector lines (especially on #1). In fact, if you touch the #1 line while the engine is running you can feel the "hammer" in there. That particular line is more prone to transmitting knock noises from a loose mounting because it spans such a long, straight distance.



I can't help but wonder if some of these injector replacements are unnecessary, when just a tighter mounting bracket would do.

 

[Johnstra]

Good suggestion. I'll try tightening it before I let them replace it.

 

[Jumbo Jet]

I drove mine about 3,000 miles with a bad injector. Was replaced about 12,000 miles ago and everything has been good. Truck has 17,000 miles on it now.



And... . the torque settings on all injectors was tested before the injector test was performed. Did not eliminate the knock.



The knock was much louder than the normal engine knock that came from my 2000 and 2002 trucks.

 

[rbattelle]

Yeah, most of them are probably bad injectors. But some of them might just be a bit loose, and it's worth a shot for a simple fix.

 

[nwjetboat]

I called the service dept. to find out just exactly how the injector failed. I guess it is sticking on small signal changes, which is causing it not to open on the pilot event. This was why they said it would be O. K. to drive. He also told me they checked to see if any were loose. They found a couple that were off spec. Also tried to clean the injector, didn't help.

I'm still going to let it sit for the weekend. .

 

[rbattelle]

Originally posted by nwjetboat

I guess it is sticking on small signal changes, which is causing it not to open on the pilot event.

This condition would be absolutely harmless, and would simply be a nuisance. Sticking closed is always better than sticking open!

 

[R.M.THOMPSON]

How loud is the "pinging" in an 600 , and does it have anything to do with the injector problem ?

 

[CPritchett]

I had the same knocking noise, especially at idle and it started doing it all of the time, so I took it to the dealer this morning and they reflashed the ecm and that helped a lot, but he isolated each injector and found two of them that needed to be replaced. He ordered them out of Dallas and they are supposed to be in tomorrow. The mechanic said sometimes the ecm causes them to run too lean and it will gall the injector and cause this problem, but there was no danger in driving with them making the noise.