OIL in Prechamber #3 in 83 SD anybody have ideas? - PeachParts Mercedes-Benz Forum

eatont9999 · #1 07-13-2012, 07:23 PM

Not sure if anyone has dealt with this before but there seemed to be a lot of engine oil in the pre-chamber of the #3 (third injector back) injector hole. The old injector was dripping with what felt and smelt like crankcase oil. It was also pretty carboned up in there. Worse than the others. I can't fathom how it could have gotten in there aside from a cracked head. I'm wondering if I have a separate issue going on that is causing or contributing to my performance and idle quality issues. I should probably start a new thread on this, though. Yes, valves were adjusted 6 weeks ago and they DID need it. No change, though.

vstech · #2 07-13-2012, 07:53 PM

I moved this topic to it's own thread for ya!

Diesel911 · #3 07-13-2012, 09:16 PM

Stuck Piston Rings as in the Rings, especially the one that Scraps the excess Oil off of the Cylinder Walls.

Things that keep the Fuel from burning properly can keep the Cylinder pressure down during combustion and that keeps the Rings from being pushed against the Cylinder Walls properly and the Oil is not scraped off well.

Valve Stem/Valve Guide/Valve Stem Seal issues.

That is all I can think of right off.

What symptoms caused you to Pull the Injector out?

Was ther somthing that occured before the symptoms showed up?

kerry · #4 07-14-2012, 09:05 AM

I'd do a compression test on that cylinder. Are you sure it's not a stuck injector putting excessive fuel in the cylinder?

Diesel911 · #5 07-14-2012, 09:30 AM

Quote:

Originally Posted by kerry

I'd do a compression test on that cylinder. Are you sure it's not a stuck injector putting excessive fuel in the cylinder?

X2 on theComperssin test.

I am curious about the Symptoms the OP was having. If an Injector Pintel was stuck or the Spring inside broken there should have been a miss fire.

eatont9999 · #6 07-14-2012, 02:53 PM

Thanks for moving this to a new thread, vstech. I was wondering where it went.

I found the oil to be concerning when I removed the third injector counting from the front of the engine and I looked down into the prechamber collar area and saw what looked like engine oil pooled on top of the crush washer and general area. I can't fathom how engine oil would get past the crush washer. The engine didn't run very smoothly before and it runs about the same as before with 5 new injector nozzles installed. A compression check is definitely a good idea. I will have to put a Diesel compression tester on my tool list soon.

The only other theory I can come up with is that what I saw was not oil and instead half-burnt and carboned up oil. I will post some pictures of the injector and pop test it as well. It is currently sitting on my bench with a trail of black liquid running from it.

eatont9999 · #7 07-14-2012, 02:57 PM

http://www.eatoncomp.com/images/83mercedes-benz300sd/injectors/IMG_1343.JPG

http://www.eatoncomp.com/images/83mercedes-benz300sd/injectors/IMG_1344.JPG

Diesel911 · #8 07-14-2012, 07:10 PM

Quote:

Originally Posted by eatont9999

Thanks for moving this to a new thread, vstech. I was wondering where it went.

I found the oil to be concerning when I removed the third injector counting from the front of the engine and I looked down into the prechamber collar area and saw what looked like engine oil pooled on top of the crush washer and general area. I can't fathom how engine oil would get past the crush washer. The engine didn't run very smoothly before and it runs about the same as before with 5 new injector nozzles installed. A compression check is definitely a good idea. I will have to put a Diesel compression tester on my tool list soon.

The only other theory I can come up with is that what I saw was not oil and instead half-burnt and carboned up oil. I will post some pictures of the injector and pop test it as well. It is currently sitting on my bench with a trail of black liquid running from it.

It is not so easy to see in the Pick but Oil from a Valve Cover leak can seep between the Injector/Prechamber Retaining Collar threads and pool in the areas the orange arrows point to.
When you pull the Injector Out there can be about 1/2 Teaspoon+ of Oil in there.

When Engine Oil is getting up into the Precombustion Chamber the resulting Carbon Deposits look wet and shiny. Normal combustion produces an even dry deposit of Carbon.

If you remove the Injector to check the Precombustion Chamber take a good look at the Ball Pin and see if it moves.

eatont9999 · #9 07-16-2012, 01:18 AM

Well, I didn't have any leaks from the valve cover gasket in that area but that doesn't mean there weren't any previously. I have only had the car for 6 months. The engine is starting to run worse than before. I notice what seems like incomplete combustion in one cylinder. I really want to get some compression readings before I put more money into the car. It could just be the new injectors settling in but I need more concrete evidence that at least compression is OK. The engine starts right up as soon as I hit the key but that just means my GPs and at least most of the cylinders have good compression. I'll put a gauge on the top of my list and test not only the compression but I will run the injectors by the pop tester again. It is possible a chunk of crap clogged one of them up. Everything was clean and I was meticulous during the install but it can happen.

I'm not sure about the ball pin. I will have to research that some more.

Diesel911 · #10 07-16-2012, 11:49 AM

Quote:

Originally Posted by eatont9999

Well, I didn't have any leaks from the valve cover gasket in that area but that doesn't mean there weren't any previously. I have only had the car for 6 months. The engine is starting to run worse than before. I notice what seems like incomplete combustion in one cylinder. I really want to get some compression readings before I put more money into the car. It could just be the new injectors settling in but I need more concrete evidence that at least compression is OK. The engine starts right up as soon as I hit the key but that just means my GPs and at least most of the cylinders have good compression. I'll put a gauge on the top of my list and test not only the compression but I will run the injectors by the pop tester again. It is possible a chunk of crap clogged one of them up. Everything was clean and I was meticulous during the install but it can happen.

I'm not sure about the ball pin. I will have to research that some more.

Concerning the Injector.

Do the Injector Cut Out Test.
If when you loosen Fuel Injection Hard Line Nut at the Injector the Engine runs that same or with little change in rpm you have located the Problem Cylinder.

Swap the position of that Injector with one of the other Injectors.
Do the Test again. If the problem moved along with the Injector you have a problem with the Injector.

If the problem is still on the Same Cylinder even though there is a different Injector there now you have an issue inside of the Cylinder.

eatont9999 · #11 07-16-2012, 08:51 PM

Diesel911,

I have done that test several times on other IDI Diesels. It is a good first step but I often find an incomplete combustion situation and it is hard to tell if the engine runs worse or not from cylinder to cylinder. I usually see a major change in idle on each cylinder. I'll still do the test on my car, though. I have had fantastic results using the glow plugs on 6.9 and 7.3 Navistar engines to diagnose an inconsistent burn in one or more cylinders. That kind of test will tell you exactly which cylinder to begin working with without pulling anything but the glow plug terminals. I imagine it would work on the 617 engines as well.

I stopped by the local Harbor Freight and picked up a compression tester for a little over $25. I'm a bit skeptical of the price but I can't afford $xxx for a high quality tester right now. I figure even if the gauge on the tester is off a little, I will get a good idea about the consistency between the cylinders. I will know for sure that I have a compression problem if I get a reading over 10% less than the rest on a particular cylinder.

The instructions say to preform the test on the engine at op temp. I'm not happy about burning my fingers off but I really want to get down to the bottom of this. I'm confident about the injectors but there are several other factors to take into consideration when diagnosing an ignition problem. I have yet to extensively investigate the rack dampener bolt, timing, timing chain stretch, delivery valves, or the IP itself. I think I am better off starting at the basics so I know I have my i's dotted and t's crossed. I don't want to throw money at something just by guessing.

Also, I do use DieselKleen for a cetane booster. I also buy my fuel from a station with high turn over. It's also nice that it is the cheapest place in town for fuel.

I noticed some haze while idling in traffic today. I looked out my driver's side window and saw some very light clouds puffing by. When I got home, I made a video of the exhaust for documentation. I know some IDI Diesels will haze and in the right light, it is noticeable. I have not yet seen a healthy running IDI haze at idle when at op temp, though. I will post the video if the haze can be seen, otherwise it won't do much good.

eatont9999 · #12 07-16-2012, 10:05 PM

After getting hot under the hood and losing the damn bolt bolt for the #3 GP, I finally figured out I can test ohms resistance at the GP controller connector. Here are the values I got on the multimeter. Ground point was the front engine hoist.

Pins:
1 = 4.5 ohm
2 = 3.8-3.9 ohm
3 = 2.6 ohm
4 = 4.3-4.4 ohm
5 = 3.5 ohm

Can anyone help me with the relationship between the pin numbers and the corresponding cylinders?

I find the readings from pin 3 to be a concern.

All readings were taken with the engine at idle op temp and 10 seconds after connecting the multimeter to a new pin.