Engine/Transmission (1998.5 - 2002) What happend to this Injector.....

[jwilliams3]

I think the holes weekened the tip.

After time a crack formed and got larger and took the whole darn tip off.



Heat, time... ... ..... crack.



--Justin

 

[Diesel Freak]

hmmm interesting



Looks like a seat hole injector tip.



Does the manufacturer of the injector anneal the tips after the EDM process has been used on the tip? Is anything done at all to stress relieve the tip prior to assembly?



was the Tip NDT'd to find any flaws prior to installation?

 

[Diesel Freak]

Originally posted by RSnaith

Its likely due to improper hardening of the tip. http://mysite.verizon.net/res06gkt/tipfailure.html

Rod, my thoughts exactly.

 

[Vaughn MacKenzie]

Lack of fuel would not cause overheating, to the contrary it would run cooler. Less fuel = less heat, which is a different scenario than gassers running lean. However a diesel cylinder/injector could run hot if you have a situation where the injection event has a longer duration, is delayed, or fuel atomization is very poor, then I can see the injector overheating. Maybe it wasn't shutting off completely. Running the engine hard to the limits for an extended period of time combined with a leaky injector would likely stress a tip significantly, and combined with any weakness cause a failure. When you run a long grade with EGTs at 1200 F and very high boost you don't leave yourself much margin of safety in a number of respects.



If no fuel was coming from the injector at all it definitely wouldn't overheat because it takes fire to create heat and with no fuel there's no fire. Plus, he didn't mention it was missing.



Vaughn

 

[Little Bill]

We had a similar tip failure in a JD6400 with about 200 hours on it. The tractor was drilling grain at the time and started abruptly started missing. We isolated the injector and pulled it. About half the tip was missing. We fished around the cyclinder with a magnet on a flex stick but never found the piece. Installed a new injector, crossed our fingers and cranked it up. That was about 5 years ago. The tractor now has 2500 hours and runs great, no smoke, normal blow by and no turbo problems.



JD analyzed the injector but only reported a weak tip, no root cause.

 

[dseabaugh]

Had a similar thing happen on one of our 4 wheel drive tractors. When I pulled the head I also found that the injector had ""pee'd" a stream to one side and melted a place in the piston. also from the increased power caused from the extra fuel the connecting rod was bent and the increased load had also turned the rod bearing blue although it and the journal seemed in perfect condition otherwise. There is no way this has not caused further damage.

 

[dseabaugh]

It is possible the boom came from an excess of unburned fuel being ignighted by the hot turbo or exhaust .

 

[BatMan01]

Thanks & Update

Sorry for the length... .



I thought it was time to come online and thank everyone who has taken the time to respond to this thread and a special thanks to those who have gone out or their way to help a fellow TDR'er. People like JR2, who as a newly wed, gave up a week of evenings to help me install these injectors and my set of twins. He also loaned me his DD SM's to get me back on the road when the tip failed. JR2's dad "Jack in Alaska" also also gets my heart felt thanks for towing my 5th wheel 80 miles back to town and stored it at his house for week until I could get my truck back. I also have to thank "ben_ak", who drove about 35 miles out to my house to see if his boroscope small enough for us to check out #6. Unfortunatly no one in my area has a boroscope small enough. And I want to also thank all who responded to this thread JR2 started to help find some answers.



Now for an update. The dealership replaced the injectorer pump and the lift pump. There were no codes but because the truck would not start and we could not get any fuel out of #1 and 3 it was assumed that the injector pump was bad. We now know that it is possible the injector pump was being presurized but the compression of #6 through the failed tip. Maybe... .

I have a fuel preasure guage with the sensor between the filter and injector pump and I have never had less than 9psi at WOT so my lift/pusher pump combo is doing their thing.

As mentioned above, I now have JR2's DD SM and the truck is running fine. There is a very slight lope (miss) but I understand that this is normal for SM's. My SOP meter says I lost power with the injector change. The EDMs that I had in were 170hp injectors and the SMs are 120hp. Maybe I only lost 50hp and what ever torque I had, I do'nt know. My boost is also down. Truck starts great, no strange sounds. Idle is normal. I am planning on pulling the turbos off this weekend and examine the internals for damage.



My question is this, without a boroscope and the desire to pull the head, is there anything else I can do to ensure that I do not have any damage that is waiting to say "hello" when I am miles between here and there and no TDR friends around?

 

[JR2]

Clayton,

Thanks for the kind words. I am looking for boroscopes that I can borrow at work. Not much luck yet, but I am trying.



John

 

[R.ebel]

Re: Thanks & Update

Originally posted by BatMan01



My question is this, without a boroscope and the desire to pull the head, is there anything else I can do to ensure that I do not have any damage that is waiting to say "hello" when I am miles between here and there and no TDR friends around?

A compression check of the #6 cylinder will tell you if you have any damage.