I just aquired a 1983 240D with 189,xxx miles. It has no power and what I would call a signifigant engine knock. Max speed I can get it up to is 35 on level ground. It is my goal to get this car back to good shape. I would like this to be my daily driver. When I bought it I knew it would be a project and I am willing to put the time and money into it. A group of my friends and I are looking forward to working on it. We all have some mechanical experience but this is our first diesel project!

This is what we have done so far (I know its kinda lame but we had to start somewhere) Changed oil, oil filter, air filter, spin-on fuel filter, and in-line fuel filter.

We are planning to do valve adjustment and diesel purge Saturday.

I need to know what I need to look for and what to inspect to diagnose the engine knock. Is there anything I can do while I have the valve cover off.

I plan on replacing the timing chain, transmission filter and fluid, power steering filter and fluid, and replacing the injector nozzles with bosio nozzles. I want to do all this but I want to get the engine knock fixed before all of this. If I have to do a total overhaul I am looking at some serious time and money so these will have to be later. I would also like to do the work myself if at all possible. I can also take any pictures that you would like me to throughout the entire process. Thanks!

what about the in tank screen. that could be pretty clogged.

I plan on changing the fuel tank screen when I replace all of the fuel lines. This is on my to-do list but I am afraid that all of the maintence repairs are back burner issues until I can get the major engine issue solved. I think I will be able to rule out the tank screen as the major power issue when I run the purge. I can run diesel through the "mini tank" and see if the power increases.

The first thing I would do in your situation is clean the tank screen and blow out your fuel lines.

http://www.peachparts.com/shopforum/showthread.php?t=166799

Blockage in your fuel delivery is probably why the car is going so slow.

Good luck.

Scott

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Scott
1982 Mercedes 240D, 4 speed, 275,000
1988 Porsche 944 Turbo S (70,000)
1987 Porsche 911 Coupe 109,000 (sold)
1998 Mercedes E300 TurboDiesel 147,000 (sold)
1985 Mercedes 300D 227,000 (totaled by inattentive driver with no insurance!)
1997 Mercedes E300 Diesel 236,000 (sold)
1995 Ducati 900SS (sold)
1987 VW Jetta GLI 157,000 (sold)
1986 Camaro 125,000 (sold - P.O.S.)
1977 Corvette L82 125,000 (sold)
1965 Pontiac GTO 15,000 restored (sold)

Knocking or nailing?? Stethoscope works well for isolating either to one or more cylinders, precomb chambers (nailing)..... wristpins or conrods at lower end (knocking). The only reason the crank conrod bearings or wristpins should fail is if the engine was run out of oil.

And since this is your first diesel project then resist the temptation of diagnosing a dead/dying engine too soon...... 189k miles is nothing for the 240D.

These cars experience problems with the pump linkage quite often. Have someone push the pedal to the metal and see if the pump arm is fully advanced. If not examine the linkage for the fault. Sometimes the rubbers are missing from the linkage as well. I suppose they rot and fall off with time. As for the knock. Loosen the injector lines at the injectors one at a time. Once you have found the cylinder that is knocking swap injectors to see if it goes away. I would tend to concentrate on the knock as well.

Barry, thats precombustion chamber nailing you're talkin about that follows suspect injector from one cyl to another. Gotta keep our terminology straight.

does the knocking decrease when it gets up to temp?
do you see any bubbles in the ip return lines
whats the condition of the inj, return lines?
have you checked the glow plugs to see if one is missing an element?
have you tested the blow-by on this engine?
is the new moter oil look old and smelly?
lastly im sure you replaced the air cleaner and ck the snorkle tube

__________________
http://i166.photobucket.com/albums/u116/OC03/240d.jpg
Current Car:
1985 300DT 55K miles

richclan responses to your questions:

Knocking does not go away or decrease when the engine is up to temperature. It increases with RPM.
No visible bubbles in IP return lines.
Injection return lines look good.
I have not pulled the glow plugs yet. However the circuit is complete as the glow light indicator is funtctional. It turns on for start and off when ready to start. There is no problem with the engine starting. I will pull the glow plugs using my multitester ASAP. I will also test the entire circuit as well following DG pictorial and instructions.
I am not sure what you mean by blow-by? I plan on doing a compression test on all cylinders as soon as my kit arrives. The one I have is not made for diesel and will not handle the pressure.
The new motor oil does look a little darker than when I put it in but as for smelly I haven't taken a big whiff. There is no coolant in the oil I know that no white/milky emulsion.
I changed the air filter and checked the hose all seems ok (no blockage). Also there is no oil blowing into the air filter or hose that I can see.

No power but starts easily? You still have not loosened off the injectors to see if a diffference in the knock occurs? That is still an essential step in my opinion.
Generally speaking an individual knock does not cause a major power drop by itself. I am still curious as to what you find by loosening off each injector line. If the noise remains across the board while doing that it perhaps would be time to check the fundemental timing of the cam and injection pump. No power and engine is noisey complaint.. That too is acomplished by following steps one at a time. Get a sequence of troubleshooting started. Without it it is very hard if not imposiible to localise anything. Mind for a site member to help. A total guessing game is played out instead.
If the engine were pretty worn it might be hard to start but still would go at least twice as fast as you are experiencing usually. Since you purchased it this way it could have been messed up by someone else or the timing chain could have jumped somehow for example. Since you have almost eliminated basic fuel supply problems you have to get serious. So far nothing really bad or unreasonable to repair has been detected. When you settle down and proceed methodically you should locate the problem. I know it is hard to do sometimes when you are directly involved.
Most of the guys on site like myself were never working mechanics. We were probably much like yourself when we first started on these old diesels. The really nice thing about these engines is that they are pretty simple compared to a lot of engines on the market today. You basically just have to get used to them. You have not moved ahead on the problem yet because you are skating by steps of proceedure I think. Although the separate fuel feed to try to see if fuel starvation was causing low power was a good approach.. Give me hell if you wish but I do not want to see you ultimatly frustrated. Crack those injector lines and give the guys some usable information to work with.
Or we can do it the otherway by looking for the low power. You may have two separate problems but hopefully not. I am not that mechanically gifted myself. If I cannot run down a problem in a very short time I do what is known as a rapid general tuneup of an engine. In the process usually the problem is found or indicated very early in the game. It never pays to assume or take anything for granted when working on a problem. Lets jointly run things to a conclusion. Edit. I just read your last post. In my opinion if the engine starts pretty easy it is basically capable of twice your present speed anyways. It is really not likely that low compression is the cause of your low power and speed. Also is there any indication or knowledge if the last owner was burning vegatable oil? Sometimes this important fact is left out. I own two 240ds as well by the way.

Record the sound of the engine and post it here on this thread. It may be possible for experienced people could diagnose it that way.

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1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

Barry

I have removed each injector fuel line individually while the engine is running. I did not totally remove each injector as I thought as soon as no fuel is going into that chamber then there will be no compression thus testing what I set out to do. Removing each injector line individually caused no decrease in the knock. Since that was the case then I thought it was not neccessary to swap injectors into different cylinders as there is no "follow the knock" type of diagnoses.

If I missed a step that you wanted me to do I am sorry I tried to follow all of your suggestions step by step in order.

I did disconected the injector lines and inspected each, as well as the return lines before I performed the valve adjustment. The camshaft look good and lobes looked good. No wear or pitting. The valve adjusting nuts and springs surrounding all looked good as well. The timing chain look good as well. I am not sure if it is the original or not? There was abosolutly no slip at all in the timing chain tension! The teeth on the up pulley for the timing chain look good as well. So far the only visible problems I can find are the oil cap has a slow leak. I created one other problem. While adjusting the valve one of the plastic fittings attached to a vacuum valve broke off and now I have to hold that vacuum hose to the valve to get the car to shut off when the key is turned of.

I will try to record the sound as soon as I can. I have to go search my computer parts for a microphone as I don't have one handy. Thanks again for all of the help.

Sorry forgot to mention. There is absolutely no indication that the previous owner ran VO in this vehicle. When I removed the old fuel filters I examined them. They both looked what I would expect to be normal for diesel fuel. No residue or oil or high amounts of particulate. I believe it was driven by a high school student as his first car and got a new car. Maybe he got a new car because of the issues I am encountering. I knew this car had some issues and I look forward to finding them and addressing them. That is why I purchased this car. I want to be able to work on it, enjoy it, and learn all the processes. I will go a methodically as possible through all of the steps. My friends and I needed a good project and I think this is going to test us but we will not give up easily!

barry123400 i couldnt say it any better, good job
FYI my 240 has alot of blow-by. it will cut out on a 3 count, however it has enough power to go 80+ mph in the flats. much slower uphill. i also have a bad nailing problem w/cold when running straight dino. the nailing went away entirely when running blended WVO/dino
definately ck the glow plugs to see if one is missing an element, and when they are all out make sure the chambers are clear and clean. if your missing an element it might have damaged something on the way out.
hopefully all this is for you, is the ip timing is wack. on a gas engine w/timing is off alot they have similar symptoms as you have, except the knocking.
good luck

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http://i166.photobucket.com/albums/u116/OC03/240d.jpg
Current Car:
1985 300DT 55K miles

Richclan, periodically check your shut down time. I am not sure yet but if using unheated vegatable oil I partially believe the compression rings may be coking up. If oil really heated should not be a problem. I have an almost pristine example of a 1984 300d turbo car that ran unheated vegatable oil. My shut down time is about three seconds as well. I have no history at all on the car other than it ran 100% unheated vegatable oil. For how many miles is also unknown. It is crazy to blame it on the unheated vegatable oil he burnt of course. On the otherhand there is no way the car has more miles on it than indicated and they are fairly low. The interior does not even look like it even was sat in ever. I am going to try to drive those rings loose with dino and additives first. Then if that does not work someone suggested soaking down with miracle oil might dissolve the coking next. I suspect though if there is no improvement I will eventually be doing something with those rings. I also feel the oil control rings are perfect in that engine. I am not anti vegatable oil but really feel it should be heated. Otherwise a small percentage may hit the walls of the cylinders wet and land up coked in the upper ring lands. Also we have another thread started with a thirty mile per hour 240d special since this one. In addition I once drove 19 hours to pick up a museam example of a 240d.I hope the cross information helps them both out. It exhibited the same performance. Would accelerate to about 30 and drop back to 25. I suspected the fuel filter on that one. The car was really bad otherwise as well so I did not even troubleshoot it on site. Thank goodness I never paid for cars in advance of picking them up when purchased on ebay. Ebay is far riskier than it was in those days now. I never buy 123s or simular on site anymore. You can really get burnt so I stay away. Kind of too bad for those really honest vendors out there. A lot of us early ebay car buyers have dropped out. The odds are against us now. I feel particularily bad about the 1999 mercedes diesel that was sold to an american from the nearby town on ebay. It did not go cheap as had very low miles. It was well cleaned up but had been in salt water. With their electronic systems it should be one thing after another until all is replaced or the new owner sells it. You do know where it will be sold. That salt water immersion will probably not show up anywhere like carfax or on the title. Kind of temporarily borrowed this thread as the originator is getting ready for this evening I believe. He may forgive me. Just general interest stuff anyways.