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On 8/13/2021 at 1:51 PM, Mopar1973Man said:

 

They could be... I've done several truck where your just changing injectors and having problems getting started because of weak starter, bad starter cables (positive or negative), bad starter brushes, bad starter solenoid contacts, etc. Speed is key to re-priming the system with the starter alone. Yes I'll admit I've had to dust the mouth of the turbo with a bit of starting fluid to get the truck started. 

Must of been another member I just read about compression being low so that is my mistake... 

Remember the shop vac hose in reverse to blow in the fuel tank building a small amount of pressure pushing fuel all the way? I had a couple very stubborn primes, difficult restarts, that I got to start this way...:whistle2:

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  • 6 months later...

I know it has been quite awhile but I finally got back out to my truck to take another look. I've been saving dreading the worst (complete rebuild) I brought 2 new batteries and it finally turned over and started but you could tell it was not firing on all 6. It sounded like an old Kubota. I double checked that all 6 fuel lines where getting fuel and then after that did not change anything I ran a compression test on all 6 cylinders and got 450psi or pretty close for all 6. So now I am almost sure that there is something wrong with my fuel side of things. 

 

If anyone has any tips I'd greatly appreciate it.

 

I was thinking of just getting another set of injectors since that is the next cheapest thing to replace. 

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I don't know the exact mileage but I do know they are only about a year old. The only reason for thinking injectors is that they got put in a bag with other parts and it had a bunch of oil in it. I don't know if that could have clogged them or messed them up even more. 

 

Also it's pretty evident that there is cylinders not firing. I looked up videos on 2nd gens in 3 cylinder mode for warming up and it sounds very similar but my truck is shaking quite a bit.

 

I'm going to triple check the timing when I am out next just I'm case I missed something. 

 

My question for you @Mopar1973Man is with a compression test could it still be bad cylinders even though the compression test gave 450psi? 

I didnt do a leak down test as I didnt have the equipment for it. But i would think that if I'm getting 450 on all cylinders they should be fine.

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5 hours ago, Tex_usa said:

it finally turned over and started but you could tell it was not firing on all 6.

 

How long did you run the engine? Sometimes it takes a couple of minutes to remove the remaining air from the rest of the injector lines while it is running.


Before I would pull any injectors or perform any time consuming work, I would remove the valve cover and start the engine.  Don't worry, it will not make a mess.  I would then observe every intake valve and every exhaust valve for full travel of operation.  If any valve is not opening or only partially opening then you have narrowed down the problem.   

 

If everything is normal in the valve train, then I would crack each injector line individually while the engine is idling.  If the engine rpm does not drop when an injector line is cracked, then that cylinder is not performing its share of the work.  Test all six cylinders in this manner.  Note which cylinders are not performing.  This will not tell you exactly what the problem is, but it will tell you which cylinders are affected.  This will save you some troubleshooting time and narrow down the cause of the problem.

 

Sometimes the art of troubleshooting is not picking something that could be the problem and jumping into it, but instead, it is to methodically eliminate potential sources of the problem that are easy to perform with results that are conclusive.

 

- John

 

 

Edited by Tractorman
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@Tractorman Thank you! I saw in another post someone said to crack while running to see the difference or use a laser thermometer to tell which cylinders are not working. 

 

It is a new head that I put on it so it very well could be something wrong with it that I assumed would be working just fine.

Is there a good way to tell if the vales are traveling correctly? 

I will go ahead and look this up as well.

After a quick look online I basically just need to make sure they are moving up and down for the most part.

 

One post said that they received a new head with the exhaust and intake valve that were not in the right spot? But from what I could see on the 2002 cummins it is only a difference of .3mm between the two valves. Should I be worried at all about this?

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7 hours ago, Tex_usa said:

The only reason for thinking injectors is that they got put in a bag with other parts and it had a bunch of oil in it. I don't know if that could have clogged them or messed them up even more. 

The answer to your question is yes, injectors should be stored clean, I'm guessing the oil is just oil off of the injectors and other parts so not even new clean oil

As has been said find out 100% which cylinder/cylinders are misfiring either by cracking injector lines one at a time while running and see the change in rpm, cracking a line to a good injector will either lower rpm significantly or stop the motor, a bad one will have little or no effect, or use a heat gun to test exhaust port temps.

If any are bad pull the lot and at worst have them tested by a good fuel shop or replace.

Any injectors I change I always keep the plastic caps that come on the tips and inlets and reuse if needed once spotlessly clean, I also have a large Cat box of plastic plugs and caps which I use all the time

My guess is dirty old oil has got into injector inlets, or possibly a tip, that is more than enough contaminants to cause a misfire

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5 hours ago, wil440 said:

My guess is dirty old oil has got into injector inlets, or possibly a tip, that is more than enough contaminants to cause a misfire

 

Back to what I was say have the injectors pulled and pop tested and see. 

 

I did an article a while back on how to clean them. The bad part is not being able to measure pop pressure.

 

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Could it be the crossover tube on a cylinder or two are cockeyed? In Mike's article there is a specific procedure given for tightening tubes and injectors.

I'm no expert in this, it's just a thought.

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7 hours ago, LorenS said:

Could it be the crossover tube on a cylinder or two are cockeyed? In Mike's article there is a specific procedure given for tightening tubes and injectors.

I'm no expert in this, it's just a thought.

It could be but it would need to be some leak to cause it to run like a Kubota as Tex-usa says and would be adding fuel to engine oil 

Looking at the injector shape where the crossovers sit it is also not possible to get them so badly aligned that the injector inlet is blocked off but that's not to say tubes aren't blocked or were contaminated and blocked an injector

Finding out which if any are not firing then inspect/test  injector/injectors and then go from there will find the problem

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Basically the cross over tube needs tightening first so the injector can move to self align. Then you can tighten the injector hold down to 89 in-lbs.

 

Matter of fact is just replaced my injector body o-rings because after the head was service last the o-rings where bit small and injectors fell into place. This was possibly the loss of prime issue. Find out this morning when I start it up. Only took an hour to do this.

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11 hours ago, Mopar1973Man said:

Basically the cross over tube needs tightening first so the injector can move to self align. Then you can tighten the injector hold down to 89 in-lbs.

 

Matter of fact is just replaced my injector body o-rings because after the head was service last the o-rings where bit small and injectors fell into place. This was possibly the loss of prime issue. Find out this morning when I start it up. Only took an hour to do this.

:doh: I gotta go back and fix this. I tighten the hold down first.

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  • 1 month later...

Ok back at it again after a long month of changing jobs again  :doh:

I started it back up and it would run but still sounded like it was only using 2 cylinders (I went and looked up some that were running in 3 cylinder high idle and it was more choppy then those)

I started with cylinder #1 and losend the fuel line and it shut off right away. 

 

After that I did the same thing with cylinder #3 and #4.

#3 the truck would die but #4 nothing changed.

I did note that even when loosening #4 there was fuel coming out when I got it lose enough but it didn't seem to be spraying as hard as I would have imagined. (If you have a video or know one so I could compare let me know)

 

After that I tried swapping injector #1 with injector #4 to see if I could see a heat difference in the exhaust but the truck would never start so swapped them back and was able to get it running again but sounding like it was just 2 cylinders working.

 

When I had it running I did check the exhaust manifold and the first 3 were getting warm but the last 3 were still cold.

 

I don't know if any of yall have seen this before but I figured I would post what I found.

I'm thinking about getting a set of injectors just to rule it out as they are not as expensive as they used to be.

My other thought is that the injection pump is failing.

 

If you have any thoughts let me know! I appreciate all the advice you have been throwing at me!

 

All of that said I did get a video of it running but I'm pretty sure it would be to big to upload so I am looking at how to do that.

I think this may be the best way to share the video.

Sorry if the quality is bad I only really wanted the sound.

 

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