0 to 60 in 30 seconds is annoying and very frustrating. i'm certain there is something wrong that can be fixed/adjusted to get her moving just a tad faster. at 210K, im not expecting to get her back original specs of a new or much younger non turbo 300cd. need some help. thanks.

When were the valves adjusted last?

Check under hood for any throttle linkage deterioration. Have a helper step on the go pedal while you inspect the various bushings.

New air cleaner?

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83 SD

84 CD

Maybe it's time for a signifigant engine check and tuneup. A little bit of one thing wrong combined with other issues all add up. It could be primarily only one thing but there are quite a few choices for that.

Did you ever even put new fuel filters on? Contrary to many opinions diesels are not an ever ready battery. Things need checking with time and usage. If not done systematically overall performance will suffer. There is no reason if the compression is good that like new performance cannot be restored. As mentioned above a large percentage of older mercedes diesels have not even had their valve clearances checked for a very long time. Yet mercedes recomends an every 15K interval.

Also it is wise to check your timing chain for stretch if you are not aware it was replaced some time ago. Not checking the chain and chain guides can cost you an engine, The same as obviously ignored oil cooler feed hoses that are weeping. What kind of fuel pressure is in the base of the injection pump? Linkage wear to the injection pump is also to be suspected with age and miles. With the basically step by step proceedures in the archives all of this is manageable by the average guy.

The answer I came across some yrs back was given to me by jimmyl and is a very easy fix ,a vacuum assisted line that runs from the back of the aluminium air intake to the trannie.It has a 13 mm bolt that is a banjo style design ,its open in the center and has side runner openings on either side.This has a clear line attached and youll be cleaning the carboned up line and bolt.The difference was like day and night when I stepped on the peddle ,almost a new car.

Is this only on the turbo cars, or is it on the older 300CD's as well?

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2007 Dodge Ram 3500 Cummins Turbo Diesel 4x4
1994 GMC S-15 pickup 4.3 5MT
1985 300 SD
1978 300 CD
1962 220-S Fintail - awaiting restoration

Is it shifting at the correct points? My neighbors 240D was like yours-sssslooooooooooooow. Went for a ride with him and it was shifting all gears WAY to early. We adjusted the Bowden rod and it was like adding turbo- she's like a new car

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'89 300SE
'02 E320 Wagon

That is the pressure line which transmits the turbo pressure to the IP: more turbo pressure, more fuel available.

It is only there on turbo engines.

It seems like you are getting slower. Think i remember last time you were talking around 20s 0-60?

I say that counting seconds zero to sixty in a 617 non turbo Benz is not really such an important statistic. If you are certainly timing 0-60 in your car at 30s then you are on the slow side of normal. Mine can do about 18s today.

Point is, the non turbo diesel benz is not a "fast" car. However, it is plenty powerful enough to maintain luxury on todays roads. It's not going win a 0-60 drag race with 90% of the vehicles on the rd. 80-90 MPH is going to be the max on the highway.

But not to understate its capabilities, It does have its strengths.

Whats your 0-45 time?? 2nd and third gear shout tear pretty strong. When it hits fourth at about 55 its at the low end of highest gear it will be slow to get that next 5mph.

Whats your high speed like?? Despite its shortcomings in stop and go city type driving. This car is a beast on the highway! I set the cruise in mine at 75 and just lean back. I sometime see ppl do a double take when the realize what kind of car it is passing them.

I do believe that your car has some cause of diminished performance. key is figuring out what it is. You can go the "fix everything" route or you can go the "pinpoint" route. Just realize that you're going to want to keep track of what you've changed. If you start messing with this you could start to see thinks happening with that. Know what i mean?

Provide the forum with list of everything you have done in attempts to regain your performance and the forum will generate a "checklist" of things you need to do.


Is there Power Hiding somewhere wanting to come out?? or is your engine old and abused tired??

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Current fleet
2006 E320 CDI
1992 300D - 5speed manual swapped

former members
1984 300D "Blues Mobile"

1978 300CD "El Toro"

For it to be that low I would suspect Alda or transmission shifting. There is a contraption on the valve cover with some cams and vacuum valves. It simulates the vacuum signal that would come from a gas engine for the modulator valve to operate the transmission correctly. There is also a valve on the back of the injection pump that has to do with this.

Hope this helps,
Whip

Adjust the Valve Clearances. Don't do another thing until you do this!!

__________________
Current fleet
2006 E320 CDI
1992 300D - 5speed manual swapped

former members
1984 300D "Blues Mobile"

1978 300CD "El Toro"

guys you have pointed to so many things - may head is spinning.
i'm going to break all these recommendations down and carefully take it one step at a time. pls note: i truely enjoy bringing my car along by turning my own wrenches.

things i've done: changed both under hood fuel filters, fuel hoses and glow plugs. sad to say but, that's about it, so far as fuel delivery goes...

took a look at the air filter and yes - it needs replacement immediately!
Phillytwotank says, valve clearances should be priority one... and i believe there is something to be gained in proper ajustments to the transmission vacuum valves. this is a tuff area for me to understand...

more performance info: the frustration really exist in acceleration from 0-35 after 35 to 40mph (all thing considered) i'm very satisfied with acceleration. i haven't taken her much beyond 70mph because a sway problem at these speeds. the drive train is ready to go +80 no problem. she responds to the pedal very well after 35mph.

narrowing things down... acceleration from 0-35 is the immediate problem. does this narrow things down on where the problem is more likely to be?



thanks

You definitely want to replace the air filter, but I don't think it will be your problem. A plugged air filter on a diesel will cause poor fuel mileage though. It's kind of weird, but that's the way it works.

Do some looking into the ALDA. Learn about what it does and how to adjust it.

Whip

Phillytwotank says, valve clearances should be priority one... and i believe there is something to be gained in proper ajustments to the transmission vacuum valves. this is a tuff area for me to understand...


Phillytwotank was refering to the intake and exhaust valves under the Valve Cover.

Charlie

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there were three HP ratings on the OM616...

1) Not much power
2) Even less power
3) Not nearly enough power!! 240D w/auto

Anyone that thinks a 240D is slow drives too fast.

80 240D Naturally Exasperated, 4-Spd 388k DD 150mph spedo 3:58 Diff

We are advised to NOT judge ALL Muslims by the actions of a few lunatics, but we are encouraged to judge ALL gun owners by the actions of a few lunatics. Funny how that works

Great start. You're moving down the "fix everything" route and that's fine. Go ahead and replace that air filter.

Yeah. Valve Clearances are referring to THE valves. Air intake and exhaust valves under the valve cover right on top the engine. Improperly adjusted valves would most definitely cause poor acceleration.

Options for Service - DIY! if you're willing and able do the wrenching on this benz and you plan on keeping it around for a while then you should definitely learn how to DIY. I would make an unsolicited referral to mercedes source dot com for their valve adjust DIY kit. Comes with the special wrenches valve cover gasket and DETAILED instructions. Its not a particularly difficult job but there are definitely certain idiosyncrasies about it that will make or break a successful valve clearance adjustment. All of the info and tools are available out there on this forum, i would just refer you to that for ease and convenience. All together set you back aboout the cost of paying a competent mechanic to do the job once.

which brings us to the other option - Competent Mechanic. My guy is very good. 35 plus years in business and he loves the old diesels. He can get me out the door with clearance adjusted,timing chain stretch check,new gasket,lube + adjust throttle likages for $90. If you can find someone like that in SE VA then maybe that's an option for you.

My '78 CD was originally from SE VA, VA Beach. it came from Phillips Mercedes of VA beach. I see that they are still in bussiness. Maybe they can refer you to a reputable mechanic??

If you get that valve job and you don't see improvement then there's at least two more things that are easy checks. valves First tho please.

It be like trying to run without bending your knees.

__________________
Current fleet
2006 E320 CDI
1992 300D - 5speed manual swapped

former members
1984 300D "Blues Mobile"

1978 300CD "El Toro"

Not in my mind. Unless the transmission is shifting up too early. You should hear this though and it should be pretty obvious.

As a long shot I wondered if the lift pump may be delivering marginal fuel at low rpms yet semi restores better fuel pressure at higher ones.

If the difficulty is outside the block and injection pump they are pretty reasonable to restore.Actually downright cheap other than some time. Internal serious injector pump issues are not all that common.

A quick test that costs nothing although I am kind of mentally hung up on fuel supply issues. As I said costs nothing and is just an indicator of where to perhaps look.

Close off the fuel return from the injection pump temporarily and take the car for a spin. Any evidence of major improvement means that system should be looked at a little closer. You will hurt nothing by doing so.

The system still remains suspect even if there is no improvement but it is still a quick partial test for very low fuel pressure . If there is no real improvement then open up the return line to see if excess fuel is flowing back to the tank at idle if you cannot see it visually. Or even better do it before the clamp off test.

This is just to establish that enough fuel volume and pressure is probably there. It unfortunatly is not totally conclusive but generally speaking can indicate a few places to look if it fails either one.

As a general rule on these older indirect injection engines. Oil consumption in miles per quart is an indicator of internal condition.. A decent engines overall condition if good should also fire off quickly.

Anyways, have someone press the fuel pedal to the floor with the engine off while you examine if the lever on the fuel injection pump is being pushed to the injection pumps stop first of all.

Next check the valve clearances. Both these should be done before anything else. Other than two of the three fuel filters that you have already done.

Both valve and linkage are wear related and common issues. If you can do your own labour these cars are a reasonable proposition to bring back to decent condition usually at least mechanically. For those that must farm everything out not all that practical in todays world. By and large they are easy to work on is a bonus as well.

This sites existance makes it almost a piece of cake. I have even thought these older diesels can be a great learning experience for a son. Newer cars are almost too complex to start them off on. Some hands on knowledge of cars should be an integral part of their education anyways in my opinion.