'83 300D intermittent missing/knocking/ticking- i feel defeated (video included) - PeachParts Mercedes-Benz Forum

dinman · #1 10-18-2017, 11:52 PM

Going to try and make a long story short. purchased this car for a mere $400 and i would love to bring it up to snuff. Here it is

No Bueno

I have done the following- yet i STILL have this ominous sounding knock/tick/misfire. Its actually 2 different noises. One is a high pitched tap, one is a nasty sounding knock, accompanied with the engine missing. Happens occasionally at running speed, but rare. Happens more when cold.

Car has unknown mileage (243k) on halfway working odometer, and unknown maintenance. ive done the following in the past 2k miles ive had it:

Valve adjustment (4 times)
Rebuilt injectors w/ Monark nozzles torqued to 58 ft lbs
water pump
alternator
both alt brackets
belts
air cleaner bracket/mounts
diesel purge
both fuel filters (twice)
return lines
oil change (twice)

and other things that wouldnt pertain to this issue such as brakes, seats, wood, wheel bearings, etc

Let me note one thing that may be essential- the #3 valve (intake on cylinder 2) will not adjust into spec. the nut seems stripped, not only on the hex portion (can only fit the wrench on one side of it) but also on the valve. No matter how much i fight it, i cant get the clearance to close. The closest i can get it is over .020, when i know it is supposed to be .004 for intake on the om617 turbo. all other valves adjust perfectly.

going to check the valves again tomorrow

could it be a fuel delivery issue? the car sat for 7+ years before i got it and i havent touched the tank.

it sounds horrible, i would say it is catastrophic engine failure, but it comes and goes. I would believe if the engine was about to pop, the noises would just get worse and worse.

Sometimes it drives great, and sometimes it does terrible.

Oh, and after installing the injectors with new nozzles, it smokes A LOT. Like before i never got any smoke. Now, it smokes pretty heavily on start up (when cold) and is puffing out a faint haze most of the time when driving. But the old injectors were for sure trashed, i couldnt even see the tips of the needles on some of them.

Of course it didnt do alot of what it normally does in this video im posting below. You can defintely hear the inconsistant high pitched tick, and the loud knock/misfire only happens once or twice. Once at 0:06, and once again at the 2:22 mark of the video, right at the end before i shut the camera off. Its a loud "knock" where the engine makes one violent shake, then goes back to normal. It does it sometimes when driving, but not often. Feels like a surge of power when it does it.

Oh by the way, my exhaust is off right now (in the process of putting it back on) so some clattering and noises can be heard because the pipe rattles pretty bad down there.

and yes i need to adjust my linkages bad. i think my idle is too high. i also need engine mounts

https://www.youtube.com/watch?v=gnAYVBcbuqY

any help would be oh so appreciated. will buy you a beer, if we ever cross paths. this car is really frustrating me. every time i fix something, two more things go wrong. but hey. "nothing more expensive than a cheap mercedes"

Junkman · #2 10-19-2017, 08:12 AM

Begin with what you see. Figure out what has to be done to adjust the valve. Is that fuel leaking at # 1 & 2?

dinman · #3 10-19-2017, 09:19 AM

Quote:

Originally Posted by Junkman

Begin with what you see. Figure out what has to be done to adjust the valve. Is that fuel leaking at # 1 & 2?

whoops, meant to explain that. i just changed oil and made a mess. spilled it all over the engine. i will say, after running the car at highway speeds for a long period of time, the #3 injector leaks a little at the halves

Maxbumpo · #4 10-19-2017, 10:17 AM

OK, I love threads like this!

My approach in a case like this is exactly what Junkman said. Begin with what you see and know to be wrong, and fix that.

Smoke after the "new" injectors: Sounds like this was a DIY job? Did you use a test stand to set the injector opening pressures? If you did not, you need to get the injectors calibrated to make sure they are set correctly for your car. If you don't want to invest in the test stand or make your own, find a local Bosch service shop that does diesel injectors, they will probably charge you $20 or so per injector to test and set the pressures.

The valve that you can't adjust properly is REALLY concerning to me, combined with the intermittent "clunk" noise in the video at about 6s and 2m:22s. I would not drive the car until that is fixed, this should be your highest priority.

On your injection pump, I see a white knurled knob for the priming pump. Replace that with a new Bosch primer pump, which is a small black cylinder, costs about $25 or so? Been a long time since I did that job. The original white primer pumps have a very bad reputation for allowing air to leak in and fuel to leak out and let the injection pump lose its prime which makes the car very hard to start and may lead to other issues, like poor running.

Maxbumpo · #5 10-19-2017, 10:20 AM

The fact that the noise and behavior is intermittent means to me that the engine is sound and is worth fixing. The repair(s) can be relatively low cost if you turn your own wrenches.

Junkman · #6 10-19-2017, 10:54 AM

Smoke may be injector related. If you didn't pop test accurately, either do them again or see whether Greazzer can be bribed out of retirement. He has all of the required stuff and has been through the learning curve.

dkr · #7 10-19-2017, 02:12 PM

I would figure out how to adjust that one valve before going through any of the other steps.

It has been mentioned before, but did you pop-test the injectors? If not, you are taking a large guess assumption that they are in spec.

Dkr.

ChrisArnt · #8 10-19-2017, 02:32 PM

I bought a car that was only driven around the block twice a year for the last 10 years.
Algae in the tank.

I can't give you advice on the mechanical technical stuff like popping the injectors or whatnot., but I would just keep pulling that secondary filter and flushing it.
Also, try 1/2 quart of marvel mystery oil in the engine oil. It may free up some stuck lifters or clear out some plugged channels.

renaissanceman · #9 10-19-2017, 02:40 PM

Quote:

Originally Posted by ChrisArnt

I bought a car that was only driven around the block twice a year for the last 10 years.
Algae in the tank.

I can't give you advice on the mechanical technical stuff like popping the injectors or whatnot., but I would just keep pulling that secondary filter and flushing it.
Also, try 1/2 quart of marvel mystery oil in the engine oil. It may free up some stuck lifters or clear out some plugged channels.

There are no lifters to stick in this old beast, right?

dinman · #10 10-19-2017, 02:58 PM

wow thanks for all the replies. i have parked the car and im not driving it until i figure this out.

I ordered the nozzles from mercsource brand new, and properly lapped and thoroughly cleaned all the surfaces. i almost believe the injectors had never been serviced they were so bad.

but no, i actually did not pop test them, 1.) being i didn't want to buy all the stuff just to do it once and 2.) no one in my area even wanted to TOUCH the injectors. all shops local to me like to say "everybody stopped wrenching on those cars ten years ago, give it up" to hell with them

im pulling the valve cover again today to check everything out.

my primer pump actually always leaks, and when i begin to pump it, it really starts pouring fuel out. This isn't normal i suppose?

Sorry for my lack of knowledge on this car. I've never owned/worked on a diesel, much less a mercedes diesel. I'm only 21 so i have never been around these cars. my interest for them sparks from my dad owning them back when they were new, and it's just such a cool car to me.

so i'd love to get it back in good reliable shape. i have hope in this engine since the noise is intermittent.

renaissanceman · #11 10-19-2017, 03:22 PM

Getting the injectors pop tested is critical for good running. As is correcting any (even slight) fuel leaks -- they introduce AIR on the suction side of the lift pump.

The rack damper can be adjusted:
http://www.peachparts.com/shopforum/diesel-discussion/309971-1985-300d-rack-damper-adjustment.html

Maxbumpo · #12 10-23-2017, 03:25 PM

Quote:

Originally Posted by dinman

my primer pump actually always leaks, and when i begin to pump it, it really starts pouring fuel out. This isn't normal i suppose?

No, you need to replace that. Bosch makes the replacement, looks nothing like your white pump. The new version is a small black cylinder, you just push it down 50+ times to prime the injection pump. It is spring loaded, and you don't unscrew it or anything, just push it down repeatedly.

Quote:

Originally Posted by dinman

Sorry for my lack of knowledge on this car. I've never owned/worked on a diesel, much less a mercedes diesel. I'm only 21 so i have never been around these cars. my interest for them sparks from my dad owning them back when they were new, and it's just such a cool car to me.

so i'd love to get it back in good reliable shape. i have hope in this engine since the noise is intermittent.

We'll get you there, ask a lot of questions here, read up using the forum search function. Get a copy of the factory service manual on CD or better yet in paper.

dinman · #13 10-25-2017, 01:36 AM

Quote:

Originally Posted by dkr

If you are running off the old diesel fuel, you are wasting your time with all of these steps until the engine starts getting clean fuel. I would be especially concerned about re-contaminating the injectors.

Dkr.

I actually ran all of the old diesel through it when i got the car. Well, i put about 2-3 tanks through it before doing the diesel purge in the way you mentioned. Did the purge twice through a "closed system" i guess you could say, then changed filters while i had my injectors out and was rebuilding them

Quote:

Originally Posted by Maxbumpo

We'll get you there, ask a lot of questions here, read up using the forum search function. Get a copy of the factory service manual on CD or better yet in paper.

i really appreciate the help guys, no other forum seems this active, esp on trying to fix the issue. the AMG guys just say "go to the dealer" LOL

anyways, on to my CURRENT issue now.

So regarding the noise i started this thread about, i did three things, and now the noise is totally gone:

Oil change
Re-adjusted valves
Ran Lubro Moly super diesel additive through a tank of fuel

For whatever reason the noise is not there anymore.

BUT. I have a new issue

I have driven the car about 200-300 miles since last posting about this noise, and YES. I have developed another noise. I swear it is always something with this car. Just installed new speakers, and reinstalled my whole exhaust system in search of a more refined ride, just to be hit with this. The sound (to me at least) seems like either a pulley screeching occasionally, or the turbocharging is failing. Regardless, the car loses ALOT of power every once in a while. By a lot, i was trying to get up on ramps to put the exhaust on, and at full throttle i could barely make it up the ramps. My 0-60 time when it is feeling "low on power"? 24 seconds. When it is feeling normal? Have not timed it, but it is leaps and bounds quicker. I would say 14-17 seconds. Noticeable loss of power, but intermittent. Such as tonight, it drove perfect until i got into my neighborhood. Here is the video. I can't tell if it is coming from a pulley, or the turbocharger. Lets hope its a pulley

https://youtu.be/560nc3ORAvA

strelnik · #14 11-08-2017, 09:24 AM

Quote:

Originally Posted by dinman

wow thanks for all the replies. i have parked the car and im not driving it until i figure this out.

I ordered the nozzles from mercsource brand new, and properly lapped and thoroughly cleaned all the surfaces. i almost believe the injectors had never been serviced they were so bad.

but no, i actually did not pop test them, 1.) being i didn't want to buy all the stuff just to do it once and 2.) no one in my area even wanted to TOUCH the injectors. all shops local to me like to say "everybody stopped wrenching on those cars ten years ago, give it up" to hell with them

im pulling the valve cover again today to check everything out.

my primer pump actually always leaks, and when i begin to pump it, it really starts pouring fuel out. This isn't normal i suppose?

Sorry for my lack of knowledge on this car. I've never owned/worked on a diesel, much less a mercedes diesel. I'm only 21 so i have never been around these cars. my interest for them sparks from my dad owning them back when they were new, and it's just such a cool car to me.

so i'd love to get it back in good reliable shape. i have hope in this engine since the noise is intermittent.

Two items:

1. Since you bought the injectors from **************, you should be able to call them and discuss whether they pop-tested them. Discuss your issues with them as well.

2. Have you replaced all the neoprene hoses which are connected to the fuel system? I once found a problem with my nephew's car, where the rubber hose at the tank was buggered. The correct fitting had been replaced with a plumbing fitting and a piece of hose. This hose cracked and periodically sucked air. Everything up front looked perfect and I went crazy looking for the problem. Found it accidentally and lear5ned to look at the whole system when I diagnosed things, not just the commonest items. So check your fuel tank area too, lol.

Good luck!

Maxbumpo · #15 11-08-2017, 09:44 AM

Quote:

Originally Posted by strelnik

1. Since you bought the injectors from **************, you should be able to call them and discuss whether they pop-tested them.

OP bought nozzles only, not full injector assemblies, so he had to take apart his old injector bodies and replace the old nozzles with new, but did not have them tested for opening pressure and spray pattern.