My glow plugs were covered in carbon after my recent injector job (with rebuilt injectors, which also included me reaming out the glow plug holes and cleaning the intake ports, but I had to reuse my heatshields, I uncrushed them before reuse) so I took off the intake, tested the glow plugs, they were fine after cleaning them, so I put my new ones in, reinstalled them and the intake and thought that may have solved my issue. I checked glow plug #5 again last week after driving around for a little and again covered in carbon.
Yesterday, I took the intake off, all the glow plugs out, and the injectors out. I cleaned the glow plugs off again, reamed the holes again, and reinstalled them. I cleaned off the injector tip and threads of the injector then spent about an hour cleaning the threads on the head where the injectors go in, cranked over the engine to get any contaminants out, then reinstalled the injectors with new crush washers. I bleed the injector lines then started it up and drove around for a while. I decided I needed to check the glow plugs this morning when the engine had cooled off to see if I had solved the problem, and I pulled plugs 1 and 2, and they were both completely caked in carbon, again.
So this has been pretty frustrating. I know I will have to pull the injectors and glowplugs again . Does anyone have an idea of what could be causing this?
I have a few ideas of my own:
1. There could be a compression leak around the threads of the glowplugs, I have not been able to clean those because I don't have an aggressive enough brush that is small enough to clean those threads. I'm not sure if this would effect all 5 cylinders though.
2. The injection timing is off and creating lots of soot. It has been running smoother then before the injectors were rebuilt but last night it was seeming to smoke more than normal.
3. There is some sort of intake or exhaust leak.

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Current: 1975 450SEL, 83 300D, 88 Yugo GVX, 90 300D OM603 swap, 91 F150 4.6 4v swap, 93 190E Sportline LE 3.0L M104 swap, 93 190E Sportline LE Megasquirt, 03 Sprinter, 06 E500 4Matic wagon.

My brother offered another possibility, not sure if it is possible but he suggested since we removed vacuum from the EGR, that could cause the problem

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Current: 1975 450SEL, 83 300D, 88 Yugo GVX, 90 300D OM603 swap, 91 F150 4.6 4v swap, 93 190E Sportline LE 3.0L M104 swap, 93 190E Sportline LE Megasquirt, 03 Sprinter, 06 E500 4Matic wagon.

I am not sure which vehicle you are speaking of or the mileage on the Vehicle.

A bunch of random thoughts.
The Glow Plugs are going to get some carbon on them but it should not be caked.

The Glow Plugs seal on the tapered shoulder that is right where the tip ends. If Gases from combustion were getting past the shoulder you would see carbon build up on the Threads.

There is some consensus that the Injector nozzles need to sort of seat in over the course of a few 100 miles.

After that there is not enogh info to tell.
Too much Carbon from, only City Driving on short trips where the Engine does not get a chance to warm up, Engine does not warm up properly due to Thermstat issue, Burning Oil, poor compresion, Injectors no good or not rebuilt properly, not enough Air and so on.

Be thining of things that would keep the Fuel From burning cleanly. Valve Adjustment, Valve Timing and Fuel Injection pump Timing.
Does the Engine spend a lot of time ideling.



Some People have said that when the littl O-ring in Fuel Supply/Lift Pump wore out it sucked Oil from inside of the Fuel Injection Pump and mixed it with the Fuel and the Oil Fuel Mix burns inside of the Engine.

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84 300D, 82 Volvo 244Gl Diesel

Ohh of course, I forgot to say this is my 190D 2.5 so probably not valve adjustment related with its self adjusting valves.
It has 315k miles so it could be a compression issue but I did not have these issues or really any compression issues before I did the injectors (probably not the best indicator but the car is right on the mark with its 0-60 times, the engine stops immediately when shut off), so if it has a compression leak, it is probably the glow plug threads.
Most of the driving has been city but I have been letting the vehicle get up to temp before shutting it off. It has been idling some as we adjust headlights or just let it warm up some before driving it. No burning oil (I regularly check it, but I haven't done it since the injector job as we haven't driven much at all, less than 100 miles), though I think there is a small oil leak in the valve cover (which would seem to be inconsequential here). New thermostat, no cooling system issues at all except the 3 prong temp sensor seems not to work (did not turn on aux fan at 105C when we were doing testing last year).
Injection pump was resealed in 2008 at 284k miles, not sure what all that means was done (I'm assuming maybe it was just the seals for the injector lines).The notes for the job say " Re-seal leaking injection pump*** Install new o-rings and copper washers, TQ to spec. Clean and check for leaks.--- $279."
Air filter was replaced 5k miles ago, and I have cleaned it a couple of times since then (just knocked it against a hard surface to knock the dust and occasional leaf or twig out). Air silencer was removed to increase airflow. The valve in the air box could be having issues but I doubt it, but obviously not hard to check. I did clean the intake ports so if those valves were sealing because of sludge or I somehow damaged one, that is a possibility.
Valve timing is possible, I would have to ask my mechanic if he checked the timing when he replaced the valve cover gasket last spring. If it is leaking I'll point it out to him for sure, I just need to clean the head up first.
Injection timing could be an issue, I have no clue how to check the timing of the pump itself, but understand if the injectors are popping at the wrong pressure, there could be issues. Greazzer rebuilt them and I have no reason to not trust his work but it could possibly be the injectors themselves.

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Current: 1975 450SEL, 83 300D, 88 Yugo GVX, 90 300D OM603 swap, 91 F150 4.6 4v swap, 93 190E Sportline LE 3.0L M104 swap, 93 190E Sportline LE Megasquirt, 03 Sprinter, 06 E500 4Matic wagon.

Was the Crbon on the Glow Plugs a dry flat black color or is it shiny.

If it is shiny black that is an indication of burning Oil.

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84 300D, 82 Volvo 244Gl Diesel

Did you measure the resistance to ground from the glow-pug connector (for each one)? Should be very low (<5 ohm). You can also verify 12 V at the glow plug during the ~20 sec "relay on" time. If drawing current, the glow plugs should get hot enough to glow cherry red (~800 F), which should cook off any carbon. As a last resort, you can remove the injector and look down the hole with the relay on and verify it is glowing. I have always done that when I had my injectors out.

Attempted reconnecting the EGR, no change. The soot is flat black. I have not checked the glow plugs myself for proper glowing but the glow plug light is coming on normally. I shall check it tomorrow.

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Current: 1975 450SEL, 83 300D, 88 Yugo GVX, 90 300D OM603 swap, 91 F150 4.6 4v swap, 93 190E Sportline LE 3.0L M104 swap, 93 190E Sportline LE Megasquirt, 03 Sprinter, 06 E500 4Matic wagon.

I had the injectors out so turned on the switch and could look at the glow plugs attempting to work. Had one burned out.

It is impressive to see how much heat they make.

Is there a reason you are inspecting the glow plugs? Poor starting?
Here is a video made
http://m.youtube.com/watch?v=R2c2IhWp15w

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85 Merc 300D - Unwinding 31 years of wear
86 VW TD
Mahindra Diesel
Iseki Diesel

In 2007 I didn't own a diesel.

I checked the glow plugs because within 4 starts of the job, the glow plug light did not come on at all and was having trouble starting.

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Current: 1975 450SEL, 83 300D, 88 Yugo GVX, 90 300D OM603 swap, 91 F150 4.6 4v swap, 93 190E Sportline LE 3.0L M104 swap, 93 190E Sportline LE Megasquirt, 03 Sprinter, 06 E500 4Matic wagon.

I want to know how do you un-crush the heat Shields?


Something that will help reading your post, break up your sentences to make it easier to read.

Charlie

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there were three HP ratings on the OM616...

1) Not much power
2) Even less power
3) Not nearly enough power!! 240D w/auto

Anyone that thinks a 240D is slow drives too fast.

80 240D Naturally Exasperated, 4-Spd 388k DD 150mph spedo 3:58 Diff

We are advised to NOT judge ALL Muslims by the actions of a few lunatics, but we are encouraged to judge ALL gun owners by the actions of a few lunatics. Funny how that works

Sounds like you used Hunter's technique of removing the GP, putting it in a vice and applying current.

Once you have verified that they work any other problems would be in the circuit such as the fuse, relay, switch or wires.

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85 Merc 300D - Unwinding 31 years of wear
86 VW TD
Mahindra Diesel
Iseki Diesel

In 2007 I didn't own a diesel.

1. Never reuse heat shields. You can't "uncrush" them. Just order a new set online.

2. Glow plugs will always have carbon on them. If it is really bad, you will have a very hard time getting them out of the prechambers. If you can pull them out with channel locks, you are in the normal range of things. If you need a slide hammer, you might have a problem -- refer to #1.

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1991 F250 super-cab 7.3 IDI. (rebuilt by me) Banks Sidewinder turbo, hydroboost brakes, new IP and injectors.
2003 S430 - 107K
1983 300SD - Tanoshii - mostly restored ~400K+.
1983 300SD - Good interior. Engine finally tamed ~250K.
Monark Nozzle Install Video - http://tinyurl.com/ptd2tge

I only reused the heatshields because I had no other car to pick up my brother the next morning. The method I read of uncrushing them was to use a large ball bearing and a vice. I used a punch and a hammer.

As far as I could tell when I took them out, they had sealed correctly and were not leaking.

I don't plan on having to reuse any again, that was a special case where I had my mechanic order some and they never came in, but that was because he thought I meant the plastic shields for the injectors (NLA), I didn't really give him enough information for him to know what I was talking about as his English is not the greatest (better than some of my teacher's though ).

I shall get a picture of a glow plug to show you what I am talking about. It is not simply normal carbon build up.

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Current: 1975 450SEL, 83 300D, 88 Yugo GVX, 90 300D OM603 swap, 91 F150 4.6 4v swap, 93 190E Sportline LE 3.0L M104 swap, 93 190E Sportline LE Megasquirt, 03 Sprinter, 06 E500 4Matic wagon.

Here are 2 pictures to show you what I mean by excessive carbon buildup

Attached Thumbnails

   

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Current: 1975 450SEL, 83 300D, 88 Yugo GVX, 90 300D OM603 swap, 91 F150 4.6 4v swap, 93 190E Sportline LE 3.0L M104 swap, 93 190E Sportline LE Megasquirt, 03 Sprinter, 06 E500 4Matic wagon.

That looks like a pretty normal amount of carbon, if you want them cleaner perform your Italian tune ups more frequently or get some alcohol injection on there

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1982 300D Turbodiesel, daily driver. Mods so far: Fram 8038 paper filter, 4 brake light mod, Gen II w126 (front) rotors/calipers, boost turned up to 12lbs, non-egr manifolds, water/methanol injection, 4-speed manual
1980 300SD Turbodiesel, project car, nearly ready to hit the street

1974 240D, New paint