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#1
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Pulling and Cleaning Injectors
Hi All,
I bought my '84 300SD about 8 weeks ago and have of course examined the service records very closely. Over the past 6-7 years, the car only had about 5,000 miles put on it-so obviously there was a lot of time spent sitting in a garage. In the past 2 weeks, I have noticed she idles a tad rough and seems to smoke a bit more than usual. I am suspecting this may have something to do with clogged injectors. Thanks to the great website by Thomaspin, I have mustered the courage to pull and clean the 5 injectors over this coming weekend. Let me ask a few things and any additional info you want to add, please feel free: 1. Is it possible for injectors to get clogged easily when a car has sat for a long time and then begins to run regularly? 2. Are clogged injectors a likely culprit when experiencing rough idle and a little excess smoke? 3. Finally, there are 2 types of heat shields available when you replace them: 7mm and 10mm. Which one should I buy? What are the differences? Any insight here would be greatly appreciated. Thanks, Bud |
#2
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When I bought my "79" 240D it had sat for a while and had the same problem. I cleared it up with some hard driving (Italian tune up) and a can of Molly Purge. Have you adjusted the valves and checked chain stretch? Rough idle and smoke at start up could be due to a bad glow plug. In other words there are a couple things you might check out before pulling the injectors that are cheaper and need to be looked at anyway.
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1985 Euro 240D 5 spd 140K 1979 240D 5 spd, 40K on engine rebuild 1994 Dodge/Cummins, 5 spd, 121K 1964 Allice Chalmers D15 tractor 2014 Kubota L3800 tractor 1964 VW bug "Lifes too short to drive a boring car" |
#3
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If the rough idle is only at start up I would have to agree on the glow plugs. I adjusted my valves and cleaned my injectors becuase I feel I should be getting more MPG. (Hate to say this...gulp...I was only getting 18 MPG)
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'85 300SD (formerly california emissions) '08 Chevy Tahoe '93 Ducati 900 SS '79 Kawasaki KZ 650 '86 Kawasaki KX 250 '88 Kawasaki KDX200 '71 Hodaka Ace 100 '72 Triumph T100R |
#4
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Thanks all for the help.
No, the rough idle is not just at startup. It's when I stop at a light, etc. Sometimes it's there, sometimes it's not. Most of the time it is. I have been put in touch with a local mechanic that does only Benzes and he comes highly recommended. Think I will take the car to him and say "Check the timing chain, do the valve adjustment, check glow plugs, and clean the injectors". Ideally, I hope one day to do all this myself, but it might be a good idea to have a pro check things out the first time. Thanks |
#5
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LubroMoly Diesel Purge
You might also try running a can or two of LM Diesel Purge through the engine.
Do not add it to your fuel tank - it will be too diluted. Disconnect the tank and run the LM neat through the engine - pix on my site. Work wonders. Then consider adding a can of Chevron Techron to a half full tank every few months - as I recall the only additive approved by MB at the time. Finally, add some Biobor Diesel Doctor to the tank to kill any algae which may be feasting in there, run the tank almost dry and refill it from a high volume pump where you are assured of fresh fuel. Algae are notorious cloggers. Then change the pre- and main fuel filters. All of this is illustrated on my site, mostly in the Cars - Technical - W126 Maintenance section. Filter changing is very simple. Use a clear pre-filter, not the milky white one. That way you get immediate visual confirmation of the state of cleanliness of your fuel supply. Performance Products, renowned for their sloppy order fulfillment, sells Biobor and LM - though I would suggest you try Gerorge_Murphy@compuserve.com first. I would try all of these before spending money on a mechanic, unless you have solid reasons to be convinced that your chain is reaching the end of its life. A 200k mile life on the 5 cyl diesel chain, if the engine has had regular oil/filter changes, would not be unusual, as the chain's path has no sudden directional reversals, in contrast to that in the V8 engines, where life can be expected to be 100k or so if you play it safe. Upper chain rails in the V8s need regular replacement also. If your mechanic advises the chain is stretched consider replacing the tensioner also - $50 on FastLane, whatever $ he can get away with at your local shop. Labor to replace just the tensioner is 30 minutes if you are slow. One more thought. Warm idle s/b ~750rpm. If you are below that you can get the shakes. It's a simple adjustment - one slotted screw with a 14mm retainer nut (needs a deep socket) between the injection pump and the engine. If your tach is inoperative/crazy, change the tach amplifier - no tools needed. Its the small black cylinder - 2" tall x 1 " diameter - on the driver's fender well. Screws on and off. Most seem to fail eventually and unless you want to resolder the blighter, replacement is the quick (if not cheapest - $74) fix. And you thought diesels were low maintenance.... |
#6
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Re: LubroMoly Diesel Purge
Quote:
M |
#7
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The chemicals can help, but there is only one way to thoroughly clean the injectors.
Get some old fashioned, caustic, soak the parts overnight type carburetor cleaner. Take the injectors apart and soak them overnight in this stuff. You may need to do them one at a time or whateve method necessary to keep from mixing up the parts. You want all the same parts from an injector to go back together only with that injector. Good luck, |
#8
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Quote:
M. |
#9
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I took Hildegard ('84 300SD) to the mechanic today at lunch.
I was pretty impressed with him. He comes highly recommended (I have a friend seriously into 190E 2.3-16's and this is the only guy he lets work on the car). he also has a reputation for honesty. He is European and he only works on Benzes--no Bimmers, Volvos, none of that. Anyway, I mentioned trying to pull the injectors myself and he acted like it was a big deal. I don't think he knew that I had really looked into this job and knew the tools, etc you need to do it right. He said I probably need my valves adjusted which I am gonna have him do next Tuesday. Yeah I know I could try it myself. but think it's best for a pro to get Hildy right the first time. |
#10
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"he acted like it was a big deal"
GoWolfpack ....these cars were designed to be worked on in a tent in the middle or the desert, well the 240ds anyway, but changing the injectors in your car is a very easy job:p . Adjusting the valves.... well it would be nice if you could see it done but if you ever had a desire to start wrenching on your car this is the car to start with Its nice you found a good mechanic that you trust, bring him a donut and coffee now and then. Steve Last edited by Stevo; 07-11-2003 at 07:16 PM. |
#11
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The MBZ engine manual details the injector rebuild process. Unfortunately, you need a rather expensive peice of test gear to do it. Although, the equipment could be built by an enterprising person.
M.
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He's wild and free and so close to it only Gunk will clean his fingernails! |
#12
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I took Hildegard in yesterday and the mechanic adjusted the valves.
Said they were really out of sync. I am trying to get on his good side and I think he will show me how to do a valve adjustment--he knows I am eager to work on the car and do things more than just putting in a new wood shifter... ... He said that 2 of the 5 injectors were not spraying fuel in a fine mist so I think I will tackle the injector cleaning next weekend... I would this weekend except I have to helo my girlfriend buy a new car--Acura MDX. Too fancy for me.... |
#13
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Cleaning the injectors is not a big deal, just time consuming to get everything soaked. As long as you don't interchange parts, you will not need any fancy test equipment. That is to check the pressure at which the injectors actuate.
Cleaning them as I described will cure the faulty spray pattern. Gunk and others make the old fashioned, boil 'em out carburetor cleaner. Good luck, |
#14
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Quote:
M.
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He's wild and free and so close to it only Gunk will clean his fingernails! |
#15
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Hi all,
Ok, I know this topic has been discussed and thanks to all, but I have two final questions about this job: 1. What's the difference between the 7.5mm heat shield and the 10.0mm one? What is the basis for choosing which one? 2. Does anyone know the actual name of the bypass return hose that needs to be replaced when pulling the injectors? I went to Fastlane to buy the hose, but am confused as to which hose to buy. There is Diesel Injector Hose 3.2 x 1.2mm in 5 meter lengths for $18.88 but there is also Diesel "Cigar" hose. Which do I buy? Thanks a lot. Bud |
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