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21 comments
Active Contributor

Join Date: Mar 2010
Posts: 24

Cummins N14 Injector Problem

05/06/2010 11:01 AM

I have 2001 cummins n14 435+ hp engine. I got an engine tune up done about 4 months back. Now I got one injector dead about a week ago. And after it was fixed after a day another one is gone. Is it to do with bad tune up? or bad workmanship? fuel? I am just trying to figure out the reason.

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Guru

Join Date: Jan 2010
Posts: 2538
Good Answers: 60
#1

Re: Cummins N14 Injector Problem

05/06/2010 1:42 PM

Your just plain lucky, Injectors are not normally touched during a tune up.

But if the fuel filter was changed it could be some dirt was dislodged during this process.

i would suggest you get the fuel line from the filter flushed out asap.

and ask them to strip the two failed injectors to see if there is any dirt in them, Although of course they may deny this.

ask for a complete breakdown as to what was done on the tune up ?

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Active Contributor

Join Date: Mar 2010
Posts: 24
#2
In reply to #1

Re: Cummins N14 Injector Problem

05/06/2010 10:59 PM

thanks .I saw injectors they were like plugged.pretty plugged nd blackened.i askd them to just clean them up but they said its better to rplace nd he said another injector showing weak on diagnosis.Now i m concerned about clearing that sludge or dirt covering the tip.Is there any good diesel injector cleaners?

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Guru

Join Date: Jan 2010
Posts: 2538
Good Answers: 60
#3
In reply to #2

Re: Cummins N14 Injector Problem

05/07/2010 5:04 AM

if blackened there could be too much fuel injected, and or compression is low aiding incomplete combustion, What does "pretty plugged nd blackened" Mean ? please dont use abbreviations.

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Active Contributor

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Posts: 24
#8
In reply to #3

Re: Cummins N14 Injector Problem

05/07/2010 10:24 AM

i mean the tip of injector was full of greasy stuff.

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Anonymous Poster
#5
In reply to #2

Re: Cummins N14 Injector Problem

05/07/2010 8:18 AM

Cummins injectors unlike spark plugs are normally black and dirty appearing because they are in the combustion chamber and accumulate carbon as a normal occurrence. One way to test an injector is to check the spray pattern and see if it is performing as required. If not there isn't too much most places can do other than replace them with recon injectors. There are many possible causes for your problem among them is quality of fuel, how the truck is driven, and as mentioned earlier cleanliness of the fuel system.

How many miles have you accumulated on the present injectors?

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Active Contributor

Join Date: Mar 2010
Posts: 24
#7
In reply to #5

Re: Cummins N14 Injector Problem

05/07/2010 10:22 AM

around 7,00,000 kms.i fuel up at husky truck stations(its like pilot or flying j)

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Anonymous Poster
#11
In reply to #7

Re: Cummins N14 Injector Problem

05/07/2010 12:58 PM

Those stations usually have good fuel.

With that many kms I would say you received your moneys worth from the injectors.

I don't believe you stated why you decided to go for a tune up.

Could it be the injectors were coming due for replacement and the servicing people knew this?

I also believe those injectors are electronically controlled. They just might be getting tired.

Did they tell you how they decided the injector(s) might be faulty?

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Active Contributor

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#12
In reply to #11

Re: Cummins N14 Injector Problem

05/07/2010 11:08 PM

Well i just wanted to get tune up done just for sake of better drive and all that.And injectors were gone bcoz engine check lite came nd i started loosing power.It was first and next day another one .One had solenoid gone and second had tip gone as i told it was all clogged with greasy stuff i think carbon

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Anonymous Poster
#13
In reply to #12

Re: Cummins N14 Injector Problem

05/08/2010 5:10 AM

Generally, when we refer to a tune up on a Cummins, It involves adjusting valves and testing the injectors. We don't know what the service people did in regard to the injectors, but, if they saw what you state as the condition if the tips, they should have consulted you about this before putting everything back together.

I'm wondering if excess oil isn't getting in there. I have seen Cummins engines with excess oil run like a bear due to the extra (hydrocarbons) getting in there. Did the check engine lite go away after they changed the defective injectors? Shouldn't rule out an electronic problem controlling those injectors possibly from rough handling at time of tune-up. Is this vehicle used over the road or locally?

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Active Contributor

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#14
In reply to #13

Re: Cummins N14 Injector Problem

05/08/2010 10:16 AM

truck is used for just city work.They adjusted valves nd set injector height ,nothing about cleaning injectors.yes engine check lite went away.

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Anonymous Poster
#16
In reply to #14

Re: Cummins N14 Injector Problem

05/08/2010 5:43 PM

As you are probably aware, a Cummins diesel needs to be run hard and hot or you could end up with an abundance of carbon buildup. Sometimes all it takes is a long run where the engine can really get hot and work hard and it may just clean up your carbon problem. It really never gets hot enough to burn off the soot with local driving. It might not be a bad idea to take a long run every so often to clean out the carbon buildup.

h

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Active Contributor

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Posts: 24
#20
In reply to #16

Re: Cummins N14 Injector Problem

05/21/2010 6:50 AM

thanks

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Anonymous Poster
#4

Re: Cummins N14 Injector Problem

05/07/2010 6:49 AM

Check your fuel filter. Make sure it is seating correctly in the housing. Some filters have a spring which presses them. Injectors go out if the fuel is dirty. Maybe you have spome water getting through, or wrong filter or filter not instslled correctly.

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Guru
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#6

Re: Cummins N14 Injector Problem

05/07/2010 9:15 AM

I am not a believer in coincidence.In your case, I would believe that the changing of the fuel filter(s) has allowed some contamination to pass through to the injectors. There are too many diesel fuel cleansers on the market to list here. Buy a product that someone you trust has been using. Use a heavy dose to try to clean the accumulated deposits. Next time tune up time comes, think about having the areas around the filters being serviced steam cleaned beforehand. Good luck.

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Guru

Join Date: Jan 2010
Posts: 2538
Good Answers: 60
#9
In reply to #6

Re: Cummins N14 Injector Problem

05/07/2010 10:31 AM

I am not a believer in coincidence.In your case, I would believe that the changing of the fuel filter(s) has allowed some contamination to pass through to the injectors. There are too many diesel fuel cleansers on the market to list here. Buy a product that someone you trust has been using. Use a heavy dose to try to clean the accumulated deposits. Next time tune up time comes, think about having the areas around the filters being serviced steam cleaned beforehand. Good luck.

I agree with you if its been running fine and now after service it plays up it would suggest its something they have done.

I also agree with the through steam clean of engine with attention to fuel lines and filter areas.

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Guru
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#10
In reply to #9

Re: Cummins N14 Injector Problem

05/07/2010 11:22 AM

It sort of goes with my #1 rule. The last one that touched it screwed it up.

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Anonymous Poster
#15

Re: Cummins N14 Injector Problem

05/08/2010 1:02 PM

You should remove all injectors and take to injector shop for cleaning and testing like I had too . Jerry

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Active Contributor

Join Date: Mar 2010
Posts: 24
#17
In reply to #15

Re: Cummins N14 Injector Problem

05/19/2010 10:56 AM

do i need to get tuning done after i replace the injectors.shud i remove them myself or get a mechanic to do it?

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Guru
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#18
In reply to #17

Re: Cummins N14 Injector Problem

05/20/2010 10:52 PM

Do you have the ability, and tools required to replace the injectors yourself?

If you needed a valve and governor adjustments before replacing the injectors, you will still need that done. If you did not need them before, you still don't now.

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Posts: 24
#19
In reply to #18

Re: Cummins N14 Injector Problem

05/21/2010 6:50 AM

ability yes, tools as for as i know i need torque ranch nd sockets i guess,only thing i don't hav is manual.i have seen my mechanic replacing injectors.

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Anonymous Poster
#21

Re: Cummins N14 Injector Problem

05/22/2010 7:07 AM

Before you install the replacement injectors you need to clean the bottom of the area where the injectors seat in the head. This is usually done using a wooden stick and a wiping cloth. You need to be very careful not to scratch or score the seating area where the injector seats in the head. We used to use a piece of broom handle and it worked well with the wiping cloth. It seemed to have the right angle to clean the pocket. Be sure to lubricate the o rings on the injectors before installing them. Cleanliness is important , other than that you should make out alright.

h

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