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1989 560SEC
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52 Posts
Discussion Starter #1
Ok, i have got my car running again (yay) [:)] but its really really slow. Could someone give me a list of possibilities? I know it could be low compression, and that would requier a rebuild or a new engine, right? Also, i noticed the engine was extremly grimey/oiley when i was installing my new alternator, is this common in cars this old, or could i have an oil leak? Am i better off just saving for a new engine, or is there a possibility, if i had low compression, that i could salvage it?

Edit: after doing some reading, i think i am going to go voer to autozone and get new fuel filters, becuase i just ran a diesel purge and i bet they are cloged up, i'll see if that helps some.

thanks,
Kevin
 

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1986 300E, 1985 300D
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Is it using Oil?
Does it smoke at all?
Is The 240D really supposed to be that slow?

M...


Is it using Oil?
Does it smoke at all?
Is The 240D really supposed to be that slow?

Maybe you just got used to your other cars being so much faster. From what I've heard the 240D Is very slow to start with. I know After I drive my 300D Turbo and get in the 190 2.6 I about fly out the driveway in reverse because i'm not used to all the power it has.

I don't know that much about the 240 Engine but i'm sure there is someone here that can help you out more then me.

Good Luck
 

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1994 SL320, '76 240D
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Where was the engine oiley/grimey? At the top, near the valve cover, in the middle by the ...

Where was the engine oiley/grimey? At the top, near the valve cover, in the middle by the exhaust header or down by the oil pan/engine block area? Any of those would most likely just be a bad gasket, which shouldn't slow you down, anyway.

If you did a diesel purge you should change both your fuel pre-filter (small clear one) and the main fuel filter cartridge. This should make a noticeable difference in performance. Have someone who is exeprienced with Mercedes Diesels check your Bosch Diesel Injection timing. Also, when was the last time you had your valves adjusted? Those 3 things could cause a lack of performance.

Is the car hard to start? Why do you think the compression is low? These cars are quite slow - 0-60 should be about 23-25 seconds. Like Chad said you might just be used to a faster car.
 

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1994 SL320, '76 240D
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Oh, also - when the engine is warm, take your dipstick out and see if there is alot of ste...

Oh, also - when the engine is warm, take your dipstick out and see if there is alot of steam/smoke coming out of the stem. This is blow-by. If your rings are shot (thats what causes low compression usually) then you will have a good deal of steam/smoke comming out of your dipstick. I have even seen it where the blow-by comes out of the dipstick stem even when the dipstick is still in!
 

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1989 560SEC
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Discussion Starter #5
My friend has a very well taken care of 1981 240D, and it has much much better acceloratio...

My friend has a very well taken care of 1981 240D, and it has much much better acceloration. The only other car i really drive is my moms Honda van, its 4cyl and not very fast. My 240D starts very well, the only real problem is that it is extremely slow. I have to floor it to go anywhere, and even when i do floor it, it takes awhile to get it up to 20mph. It was like this when i bought it in september, but i havent been driving it much since then. The guy i bought it said that his mechanic had got the pump calibrated just right, but i dont know if he knew what he was talking about anyways. I really think it is the fuel filters, becuase everything you have described about low compression doesnt seem to be there. The car is grmiey underneath, near the alternator, the old one i took out was really really dirty. I'm going to go check on the fuel filters right now, and go get new ones from autozone later today hopefully. Thanks for the replys, i really hope it is just the fuel filters, becuase i dont have lots of money to spend on new parts [:D]
 

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1989 560SEC
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Discussion Starter #6
One last question, my haynes manual says i need to bleed the fuel system after i put new f...

One last question, my haynes manual says i need to bleed the fuel system after i put new filters in, but i dont have a hand pump, so do i relaly HAVE to bleed it, or do i need to buy a hand pump? and if so, where would i get one?

Thanks again,
Kevin
 

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1994 SL320, '76 240D
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After you replace the filters, you need to bleed the system - you don't need any tools oth...

After you replace the filters, you need to bleed the system - you don't need any tools other than your hand and wrench. After you replace both filters, you use the hand pump thats on the Diesel Injection pump to squeeze out any air in the lines. The pump is located right on the Injection pump - It has a red or black circular handle - its a little bigger than like a silver dollar. It should say OEM or OEL on it. You unscrew it by turning it counter clockwise, then pull it up and pump it a few times untill you see and hear diesel fuel comming out. Then tighten it back up by turning it clockwise untill its tight. Make sure all your filters and hoses are tight and your done! It should show you how to do it in the Haynes manual.

The hand pump that I am talking about can be seen in the attached picture - its the one circled in red. This picture is of an OM615 - from a '68-'73 200D but the fuel system is similar to yours.
 

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1989 560SEC
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Discussion Starter #8
Thanks again for your help, i'll see if everything works tonight [:D]...

Thanks again for your help, i'll see if everything works tonight [:D]
 

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1989 560SEC
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Discussion Starter #9
Well, i did everything like you said, but there is still a big pocket of air in the prefil...

Well, i did everything like you said, but there is still a big pocket of air in the prefilter, i cant seem to get it out either, no matter how much i pump, fuel just spils out of the hand pump. What am i doing wrong? It wont start now [:(]
 

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1994 SL320, '76 240D
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I will check it out to verify, but for now I am pretty sure that the nut (22mm) for the to...

I will check it out to verify, but for now I am pretty sure that the nut (22mm) for the top of the main fuel filter should be loose - not tighened while you prime and once fuel comes out there then you tighten every thing back up. Let me go look and make sure.
 

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1994 SL320, '76 240D
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Okay here it goes, step by step:

Assuming you have changed the pre filter, then tighten...


Okay here it goes, step by step:

Assuming you have changed the pre filter, then tightened both sides of it to the hoses. Then you changed the main (screw on) fuel filter cartridge.

Okay - lets assume that everything is all tighened up: Loosen the large nut (i think it's a 21 or 22mm) on top of the main fuel filter. Now loosen the manual delivery pump (the one I described before) by turning the handle. Keep pumping the manual delivery pump untill fuel emerges free of bubbles at the nut on top of the filter. Tighten the large nut, then continue to pump untill you hear and see diesel fuel coming out of the pump. Tighten the handle and your done.

Good luck - let me know if you don't understand this or if you have a problem.
 
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