IP Destroying Injectors, GP, and Prechamber? [long] - PeachParts Mercedes-Benz Forum

Tymbrymi · #1 11-16-2006, 02:03 PM

A few weeks ago my brother tells me that the white SD is having some bad problems starting. Okay, glow plug is dead, no big deal. A few days later it starts idling rougher and an occasional, but very loud clank/clink noise is heard. Did the wonderful 'loosen the injector line' trick and found that cylinder #4 wasn't running. Took the injector out and saw that there was no more pintle!!! Well that would explain a bad idle. Also noticed that the prechamber ball was not in the right place. Didn't have the idea to actually poke it with anything though... so only ordered a new set of injectors (the rest didn't look too hot either).

Put in the new injectors, and actually thought to poke around at the prechamber ball and it was loose. The clank/clink noise was that ball bouncing around in the prechamber... Wanted to see if it would run decent enough for my brother to drive while we waited for the prechamber and tools to come in. Fired it up and it ran just a little bit better. Thought that it wouldn't be great for the engine, but would be alright for a few days. He drove it for about a week, after which I had second thoughts and parked it.

About another week later (this Tuesday) prechamber tools finally came in. I replaced the prechamber, GP, etc. I noted that the injector's pintle was still intact (was worried the bouncing ball would have damaged it). Fired it up with new prechamber and it ran WORSE!!! It knocked really really bad, smoked like crazy, and rocked really bad as well. I thought that it was just all the built up crap from that cylinder not being run for a week. So off to the italian tune up! The knock slowly went away, but the car never really got any power back. floored, it could maintain 65. Its never been that slow before...

Got back to the house and it was still idling really rough. Did the injector crack test again and found that it was really only running on 3.5 cylinders. WTF?!?!? Took out the injector for #4 and THE PINTLE WAS GONE (see pic). The prechamber ball is still intact. Okay... replaced that nice new injector (is that a warranty defect

), and put one of the better ones from the old set back in #4. No change in idle. Swapped #4 #5 injector. Injector line cracking behavior did not follow the injector.

I took a video of how the engine runs during the line cracking test:
http://video.google.com/videoplay?docid=6927372785548115014&hl=en

Something that I didn't mention earlier is that the bad prechamber has two large extra holes on the side. These holes appear to have been caused by the injector spray pattern being fubar. The head even has some *slight* indentations in the same location.

Especially with that last observation, this is my theory. This whole series of events started with the IP not functioning properly on #4. Something along the lines of badly out of time or longer lower pressure delivery, etc. This is what probably resulted in the rough starting. The IP problem caused the pintle to get damaged on the injector, which would make the injector spray a stream in some random direction. This is when the idle went to crap, and also caused the destruction of the glowplug and prechamber. With the new injector and prechamber the problem started all over again. It destroyed the pintle on that injector within 5 miles of the new prechamber being installed. Not sure about the not running with new injector and old prechamber (there was a lot of that prechamber missing, lower compression so it didn't fire often?)

I've got a big school project due this Friday at midnight, so I won't be able to do much till Saturday. I don't know anything else to do besides pull the IP from my blue car, and put it on the white car and see what happens. Anybody else have any ideas?

A chronological summary:

Cold starts are difficult
Idle gets rough, and clinking/clanking noise appear
Find injector with no pintel
Replace injector (notice that pre-chamber ball is loose)
Runs/idles/starts about the same
Car driven for a ~week (50-70 miles) with new injector bad prechamber
Replace prechamber
Destroy pintle on injector within 5 miles (the test drive)
Engine runs on 3.5 cylinders
Swapped in used injector (with pintle), no change
Swapped #4 and #5 injectors, behavior didn't follow injectors
?????

Pictures should follow in next post...

Thanks in advance for all the help!!!!!

Tymbrymi · #2 11-16-2006, 02:14 PM

Prechamber pictures....

Tymbrymi · #3 11-16-2006, 02:16 PM

Remaining pictures...

R Leo · #4 11-16-2006, 03:41 PM

Quote:

Originally Posted by Tymbrymi

... Fired it up and it ran just a little bit better. Thought that it wouldn't be great for the engine, but would be alright for a few days. He drove it for about a week, after which I had second thoughts and parked it.

Whatintheheck made you think that it would be ok to run the engine with a piece of metal loose in the prechamber? Jeez.

patbob · #5 11-17-2006, 03:05 PM

Quote:

Not sure about the not running with new injector and old prechamber (there was a lot of that prechamber missing, lower compression so it didn't fire often?)

Quote:

THE PINTLE WAS GONE

No pintle. Prechamber disintegrated. Where'd all that metal go? What damage did it do on the way out?

What's the compression on that cylinder now? How does that piston and cylinder wall look? Is it chipped or scored?

The damage was probably done shortly after that ball came loose and started beating everything to smithereens.

vstech · #6 11-17-2006, 03:35 PM

from the closeup pictures of the old PC, it looks like you or someone pulled or tried to pull the PC with the GP still installed. my guess is the pc pintle ball fell into the cylinder and destroyed a valve or piston crown, and you will mostlikely need another engine.
John

Tymbrymi · #7 11-17-2006, 03:50 PM

Quote:

Originally Posted by patbob

No pintle. Prechamber disintegrated. Where'd all that metal go? What damage did it do on the way out?

What's the compression on that cylinder now? How does that piston and cylinder wall look? Is it chipped or scored?

I don't have a compression tester, nor a boroscope. So I can't really tell just yet. All I can do is my best to get it running again and hope for the best

vstech · #8 11-17-2006, 04:13 PM

Quote:

Originally Posted by Tymbrymi

I don't have a compression tester, nor a boroscope. So I can't really tell just yet. All I can do is my best to get it running again and hope for the best

for what you have put into it so far, I would go to the nearest Harbor freight and get a compression tester. at least pull the PC back out, and look around in the motor for debris, and see if you can find a broken piston crown or something.
I bet your motor is a goner.
John

Tymbrymi · #9 11-17-2006, 04:35 PM

Quote:

Originally Posted by vstech

from the closeup pictures of the old PC, it looks like you or someone pulled or tried to pull the PC with the GP still installed. my guess is the pc pintle ball fell into the cylinder and destroyed a valve or piston crown, and you will mostlikely need another engine.
John

Was in the middle of typing a reply to this and the computer died... bleh.

I did actually pull that PC out with the glow plug installed, but the glow plug was damaged earlier, and was already at that short length before the prechamber was pulled. I didn't feel any resistance from the glow plug when pulling the PC (to be fair I don't know if I would have with a good GP in there!)

Either way, the PC ball was removed with the old PC. Hopefully all the rest of the metal that is missing exited the engine in very very very small pieces. I will pull the PC again tomorrow and look around. During the first PC replacement the only abnormality I noticed was the indentations in the head where there were the undesired holes in the prechamber. I wonder if I can get one of those little 'dentist mirrors' to fit in the cylinder with the prechamber removed?

Nearest harbor freight is about 2+ hours away unfortunately. I don't imagine Autozone's has the right adapter, pressure scale, etc?

Thanks!!

vstech · #10 11-17-2006, 04:49 PM

AZ will charge over 150 for a diesel CT, if they even can get one.
HF's website should ship it to your door...
John

Dubyagee · #11 11-17-2006, 04:51 PM

I have seen injectors look like that with contaminated fuel (Someone dumped some unleaded in one where I worked. About 50% mix). And I agree on the GP still being in the PC when removed.

#12 11-18-2006, 02:15 AM

Quote:

Originally Posted by Tymbrymi

Put in the new injectors, and actually thought to poke around at the prechamber ball and it was loose. The clank/clink noise was that ball bouncing around in the prechamber... Wanted to see if it would run decent enough for my brother to drive while we waited for the prechamber and tools to come in. Fired it up and it ran just a little bit better. Thought that it wouldn't be great for the engine, but would be alright for a few days. He drove it for about a week, after which I had second thoughts and parked it.

About another week later (this Tuesday) prechamber tools finally came in. I replaced the prechamber, GP, etc. I noted that the injector's pintle was still intact (was worried the bouncing ball would have damaged it). Fired it up with new prechamber and it ran WORSE!!! It knocked really really bad, smoked like crazy, and rocked really bad as well. I thought that it was just all the built up crap from that cylinder not being run for a week. So off to the italian tune up! The knock slowly went away, but the car never really go

All I can say is

Tymbrymi · #13 11-25-2006, 04:18 AM

Went and pulled the new prechamber and found that it had a nice big round dimple in it. Noticed a hole in the same spot looking down onto the piston. At that point I wrote the engine off... and decided to at least learn something from this big screw-up of mine and pulled the head. Didn't swap the IPs like I said I was going to...

Quote:

Originally Posted by vstech

...pulled the PC with the GP still installed. my guess is the pc pintle ball fell into the cylinder and destroyed a valve or piston crown...
John

Almost.

As I fessed up in post #9, I did pull that prechamber with the GP still in

, but I didn't think anything of it since the GP when I put it in was short (see the picture with the quarter, I bent off that flaky end piece). Apparantly it was just long enough for the PC to shear off and drop a 1 cm or so chunk of metal into the cylinder (it was NOT the prechamber pintle ball... see the pics, its on the concrete, the ball never left the PC). It actually didn't "break" anything, but for all intents and purposes it might as well have. I think the pics speak well enough for themselves...

I think its amazing the valve didn't break... and that the metal chunk is still embedded in the piston!!

Okay, so why that cylinder wasn't running is solved, but why did the new injector nozzle tip burn up in the 5-10 miles that the pictured damage was done? That chunk of metal was bouncing around in the cylinder proper... not the prechamber, so I don't see what that would have done to cause the injector to go FUBAR. Any ideas on that? IMO, something is still fishy with the IP. Unless you guys can convince me otherwise, I think that IP is trash/disassemble experiment.

As far as my options for this engine.... head could be rebuilt I think? Which from searching seems to be about $1100-1200. Do I have any options for the long block? That seems to be super expensive ($4-5k)... Can you get an individual piston (or is that a bad idea, they seem to only come as a set, and I imagine that is for a reason)? Basically, do I have any options that aren't less than a full rebuild? I'm not keeping my hopes up, just trying to gather all my options so I can figure out what to do with the car.

As I imagine everyone is going to say toasted engine... I guess I'll be parting it out for use on my other SD. If the interior of the white car was nicer, I would go about finding another engine... as it is.... I'm out my first MB, and my brother isn't too happy now that he has to buy a car...

I will always have the glowplug out whenever I pull a prechamber again!!!