Injectors 101: What is this black, tar-like stuff on the injector tips?

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I upgraded my injectors this weekend on my 98. 4 24-valve to the Bosch 275hp. Thanks to all who provided info and encouragement.

One thing I was amazed to see was the condition of the injector tips. With only 20k on the truck, the tips were completely coated with a black, tar-like material. The service manual mentions looking out for injectors that have been exposed to too much heat, but these looked liked they have never gotten hot enough.

I'd appreciate any comments as to what this indicates and/or what the general appearance of injectors are under various operating conditions. Thanks!

 

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Mine had the same stuff at 6,000 miles.

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2000 3500 Quad Cab, SLT+, 4x2 Auto, 3. 54 LSD, Camper & Trailer & Sports Options, Sliding Rear Window, BLACK. With Power Bolt Tailgate Lock, Dodge Sill Guards, Mag-Hytec Rear End Cover, LE-607 rear end oil, Mobil Delvac One Engine Oil, Leer Signature Camper Shell, K&N Air Filter, Bosch 275HP Injectors.

 

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gee i wonder what mine will look like at 500 miles ... hehhhehhehhhehhehhehe

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John W. in N. H.
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Y2K 2500,QC,4x4,SLT+,CUMMINS,Auto,TT,CS,3. 54 LSD,Driftwood,Camel LEATHER + LOADED, aspiring to BOMB !

1969 Dodge Superbee, Black on Black, 383, 4spd, BOMBed !!

[This message has been edited by Mopar-muscle (edited 01-20-2000). ]

 

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It's just carbon deposits. If you think that's bad, you should see injectors out of engines with 200K miles...

What you're looking at, for most of the length of the nozzle, is stuff - mostly unburned fuel - that has worked it's way between the nozzle tip and the hole in the head that it protrudes through. After time - and some tens of thousands of miles - this stuff fills the gap and makes the injector difficult to remove.

Engines that are worked hard tend to burn some of the stuff off the tips. If the engine runs overly hot, the nozzle tips will become blue - and all the stuff burns off where it's exposed to combustion. Normally, that much heat will ruin the nozzles, and you've probably toasted some other engine parts as well.

Surprisingly enough, it's easy to remove by soaking in a strong soap/water solution. We use a sonic cleaner with 140 degree water and a degreaser soap. Never, EVER us any type of abrasive or wire brush on your nozzle tips.




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You should never use a preposition to end a sentence with.
This problem requires congressional action.
5 out of 4 people are mathematically challenged.

'65 Power Wagon. 318, 4 speed, Crew Cab. Nope, not diesel - can't afford it. Need fuel system questions answered? Ask me, I work on them.

 

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During my recent Injector changing frenzy, I had a set installed for about 200 miles. Even they had the carbon deposits.

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98. 5 2500 QC LB 4x4 5spd, white. BFG 285x75x16
Cummins 24v w/ TST PowerMAX w/EGT and Boost gauges on A-Pillar.
Diesel Dynamics Stage III injectors. K&N In the factory air box.
SnugTop, JJ Stainless Running boards, Tow Hooks, Bushwacker Street Flares, and a Cup Smoothie

 

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power wagon , what about the deposits that can't be seen inside the cylinder ? not that there is much of a combustion chamber in a diesel , is there any way to clean the top of the piston and such wiout removing the head ??

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John W. in N. H.
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Y2K 2500,QC,4x4,SLT+,CUMMINS,Auto,TT,CS,3. 54 LSD,Driftwood,Camel LEATHER + LOADED,aspiring to BOMB !

1969 Dodge Superbee, Black on Black, 383, 4spd, BOMBed !!

 

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You'll have to discuss that further with an engine guy, but to answer it direclty... Not really. You can use something like Stanadyne Performance Formula, and it is supposed to clean out deposits. We took the head of a 200K + engine recently, and there really wasn't that much gunk in there. As I said, it collects in the sheltered area between the nozzle and head, and sometimes on the side of the nozzle that's sheltered from the air's turbulence in the engine.

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You should never use a preposition to end a sentence with.
This problem requires congressional action.
5 out of 4 people are mathematically challenged.

'65 Power Wagon. 318, 4 speed, Crew Cab. Nope, not diesel - can't afford it. Need fuel system questions answered? Ask me, I work on them.