Engine Nock ??? HELP

[TKarnas]

OK all, I know the cummins nocks and sounds like a diesel, but my truck typical noise has changed. I had this truck since 52000 miles right now its around 69000. I have a TST box and a aftermarket exhaust other than that its stock. I do not go over a 2/2 setting on the box.



Last night I thought the engine nocked a little more, enough that I asked my wife and she agrees its a a different sound. She said it sounds more like a diesel now (12 V)... . Is the motor just getting worked in? I also see that I push black smoke when I accelerate at lights or stop signs. Usually stops by 3 gear.



so is this normal?

 

[Wingate]

Sounds like an injector that is damaged/stuck... Check your engine oil level for overfilling(fuel). You might have to pull an oil sample... Short of that take it to a shop and have the injectors tested.

 

[TKarnas]

So were do I get some injectors then? a good places at a good price? I have a feeling its a cracked injector. Oil level is normal, but fuel consumption is higher than normal. Low MPG last fill up. I contributed to AC being on.

 

[JWadford]

call industrial injection, they can rebuild your injectors and they are an authorized bosch dealer

 

[MMeier]

So were do I get some injectors then? a good places at a good price? I have a feeling its a cracked injector. Oil level is normal, but fuel consumption is higher than normal. Low MPG last fill up. I contributed to AC being on.

Injectors and 'good' price do not go hand in hand on a 3rd gen!:{

 

[TKarnas]

Well I dropped it off at the shop to be looked at. I trust the owner for what he says. He does not think its the injectors but maybe the box. The concerning part is the #5 cylinder is running about 20 deg hotter than the rest of the cylinders at 1700 rpm. At idel all are equal in temp.

 

[TKarnas]

Well the shop said the #5 injector was weak but not bad. They think there might be some carbon build up on the injector. He gave me some injector cleaner and told me to run it hard... So how long do I have until it pukes?

 

[Harlacher]

Diesels do not run like gasoline engines. They need to driven like you stole them. The industrial engines we used in the Navy; electical power, Main Propulsion, and small boats all sounded and worked the best under heavy load. It does not sound like you have a problem that some good loading of the engine will not cure. I cannot hear the engine so I can't say that for sure but from the thread above nothing seems to be wrong. A temperature of 20 degrees between cylinders is not that bad. I have owned my 99 since it was new and it has over 200,000 on it and I can't tell you how many times the engine has sounded different, every time I adjust the Edge, Smarty, different roads, fuel etc they are noisy. I might be speaking out of line here and there are a lot smarter people who post but I don't see a problem.

 

[TKarnas]

Thanks for all the comments. I feel better than I did last week. Its funny Harlacher said I need to drive it like I stole it. Thats what the repair guy said !



I think I am to easy on the truck.

 

[TKarnas]

Can anyone tell me what it means to have "weak #5 injector". What should I look for if the injectors are going bad or bad?

 

[Harlacher]

The tolerance in an injector are very close and as one wears leakage can occur or the injector can pop early allowing fuel to enter the cyinder before the temperature is high enough to burn it all. The unburned fuel can cause a knock and high temps in that cylinder. Usualy a loss of power occurs when injectors go bad. If carbon builds up on the tip the spray patern is affected and atomization is inadequate so again not all the fuel burns causing a knock. On the second generation 24 vlv engines pulling the injectors is pretty easy; I don't know how hard it is on the third generation. I replaced mine with HO injectors about 6 years ago and I have not had any problems since. The injectors for my 24 vlv were not that expensive either; from the coments on this thread they must be for the third generation. I hope my explanation helps; there is a difference is unit injectors and spray nozzles. I believe that all the pressure for injection in the 3rd generation trucks in done by the injection pump and the injectors open at a certain pressure and allow the pressurized fuel to enter the cylinder. So in reality the injector is no more than a relief valve and a tip that atomizes the fuel. Again a weak one will open before it should causing incomplete burning of the fuel. My understanding anyway. I hope others can clarify or correct me if I am wrong.

 

[TKarnas]

Im starting to wish I had a 24v not a CR... Reading some post on the 24, it seems easier to work with and get the same mpg.



so with everything said and the shop telling me its a weak injector (#5) do I get them all replaced or see if the weak one improves? I have been running some diesel power cetane boost in the tanks of fuel. Suggestions?

 

[Harlacher]

My son has a third generation and he is "very" happy with it. Some things on it are cheaper then the second and some are not. Have you priced a new set of injectors? I have no idea what the cost is. Every time my truck has needed something new I have upgraded and been very happy. A new set of after-market injectors could not only increase your power but your MPG. Cummins had to derate these engines to meet Dodge specs and the potential for greater power is only limited by how much you want to spend.



It sounds like the knock you hear has convinced you that repairs are needed. Those repairs will pay off in the long run. My truck is over 10 years old, getting close to 200,000 miles and I would jump in it and head to California today with no hesitation. I have had to put money into it but each time I have a better more powerful truck. Very few times have I spent the money just to make more power; it is always an upgrade on a failed part. Now I am pushing 500 HP and I get 20 MPG on the highway. These trucks can haul a house, run the quarter in the 12's, get 20 MPG, and still be a very nice daily driver. I don't know what other vehicle can do that. Putting new upgraded injectors in your truck is an investment not an expense. If you do put new ones in; don't baby it, diesels do not like to be babied. They run their best fully loaded, temps and pressures at about 80% and they hammer along for ever.

 

[Harlacher]

I guess I really never answered your question. Has the knock gotten louder? Do you have a loss of power? Do you see a lot of black smoke not under heavy load? Do you have any gauges installed? (that would be the first thing I would do) Does the knock get louder when you load it up, going up hill or towing? I cannot hear the knock nor can anyone else so I think you are asking a question that only you can answer. Like I said before, I would not change them just because the engine sounded different. I would need more evidence, that the problem was injectors if there is a problem at all.

 

[TKarnas]

I guess I really never answered your question. Has the knock gotten louder? Do you have a loss of power? Do you see a lot of black smoke not under heavy load? Do you have any gauges installed? (that would be the first thing I would do) Does the knock get louder when you load it up, going up hill or towing? I cannot hear the knock nor can anyone else so I think you are asking a question that only you can answer. Like I said before, I would not change them just because the engine sounded different. I would need more evidence, that the problem was injectors if there is a problem at all.

There was a noticable nock over the rattle of the cummins. I did see smoke at start but nothing under way or under load as I dont haul much. The nock remained noticable only while driving. I took the truck to the person we bought it from who is respected in the area for diesel work. He said he isolated each injector and the #5 was weak and about20 deg hotter than the others. I priced injectors at about $450 a injector plus labor. Gauges are with the TST box which monitors boost, Exhaust temp, Rail psi, and other stuff I dont know how to get to. I usually just look at the exhaust temp. After we unhooked the TST box and ran the tests the noise went away. Im thinking the #5 is weak with Carbon build up and maybe some came off. I am just tryingto prepare myself for the injector bill. I am figuring it may cost $3 to $4K. Not just pocket change for me. Again thanks to all.



What should I look at if a injector goes bad... Fuel in the oil, More smoke(grey), High temps, Rattle etc... . Also trying to find a book that shows how to trouble shoot cummins. I was given a cummins site but its $100 a year ancd call me old fashion I would rather give someone a $100 to hold a book than a paysite.

 

[Harlacher]

This site is free and you will get all the knowledge you need on the Dodge truck and Cummins engine. In this thread there are numerous trouble shooting procedures mentioned that can help you with your injector problem. A search on injectors for the CR will give you a bunch more. Your $100 would be wasted; the shop manual is a must for anyone who wants to understand how the Cummins works. You have to have one before you do any work on it. A tool that reads trouble codes is also a must; I understand that the right one can also be used to isolate a bad injector. The people on this site have saved me thousands of dollars when I listened to them. When I went out on my own the cost was much higher. If you listen to them; let them know you are listening, by feedback and results they will keep helping. In this thread you have asked the same question numerous times and recieved answers. Help is available if you wish to use it.

 

[TKarnas]

Well thanks to all. Sorry if I have asked the same questions numerous times, I guess I did not understand the advise.

 

[Harlacher]

I did not mean to an *****hole here; I was just trying to pass on some advice that I have learned. I did the same as you and could not understand why someone else was not solving my problem for me. They will give you all the information you need but you have to use and get back to them on what you found and they will give you more. If you do not act on what they tell you they ignore you. At least that is what I found.



Please do not stop anything you are doing on my account.

 

[speedyjdl]

You can get injectors way cheaper than $3-4K. Just think about any other mods that you want to add in the future. A little bit too big now would be better than too small in the future. I bought 80 HP injectors and they have been nice, now I wish that they were way bigger.

 

[TKarnas]

good point on the injectors. I will need to look into that.



I called Mid Atlantic as several people have recomended them... . will be taking the truck to them in late October or Novemebr if I can get a appointment. Need to call those guys to arrange... . Great people Great prices !