i now have 2 240ds. the "new" one i, a 78 w/140000 miles, has a problem, poor acceleration compared to the 81 240d -- it will cruise all day on the interstate at 70mph, but from a dead stop, pedal to the floor, no immediate response, like a 2bbl gas carb with one barrel not opening -- and even in the driveway, if i isolate the injection pump from the rest of the linkage, push down until i am at the stop(which i already adjusted to max), there is a long hesitation, then a slow climb in rpm -- again, nothing like the 81 -- engine shows no other sign of wear, starts like a champ, not overheating, minimal smoke -- what i have done so far: ran diesel purge w/2cans, changed both filters, supplemented the lift pump with an electric, bypassed the fuel tank by running off a separate container, switched the intake and return lines, adjusted linkage for maximum effect --- what i have not done yet:check cam stretch, injection pump timing, rebuild injectors -- ?? -- and yes, i know its a diesel, a 240d, but i've been driving the 81 for over 10yrs and 100k miles, and not at all like this, something is off here

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78 240d: Mona
81 240D: Lola
77 toyota chinook: Carlito
93 chevy k1500: Cowboy

Thank you for posting your issues, perhaps the forum can help figure this one out. After watching countless hours of Kent's videos on youtube, I have learned a few things. That said, I don't have perfect memory so I will try and relate as best I can.

1. Run a compression check on the engine using a QUALITY compression checker. Harbor Freight is junk junk junk (did I say junk?) Snap-on quality is required to get ACCURATE numbers on a compression check And really, don't we all want ACCURATE numbers? If you cannot afford a Snap-On grade compression checker, check around with some diesel mechanics in your area and ask what they would charge to check the compression.

2. Perform a valve adjustment. You may need to purchase the necessary wrenches for this job. I was unable to locate these wrenches on pelicanparts.com I believe uncle Kent has these available. If you are going to hang in with these diesel engines you are going to need valve adjustment wrenches to perform valve adjustments every 15,000 miles or so.

2. Purchase new/reman diesel injectors and install. Your engine will thank you. I believe these injectors are available on pelicanparts.com

https://www.pelicanparts.com/More_Info/002017152188.htm?pn=002-017-15-21-88-M14&bc=c&SVSVSI=2294

3. Change out the fuel filters, dirty filters can slow things down. Also install a new air filter, probably about time to do this necessary service.

Do this first

don't forget the in tank screen....

It's probably needs doing anyway...

Do as qualified-merc suggests I'm just going to suggest that the valves be adjusted before the compression, just changing the order. Some of the early 616's had ring problems, mine did.

Check that all of the throttle linkage is in good shape.

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"Rudeness is a weak man's imitation of strength" - Eric Hoffer

thanks -- yes, i will check the valves before doing the compression test, but this 240 doesn't seem to lack power, it just doesn't accelerate

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78 240d: Mona
81 240D: Lola
77 toyota chinook: Carlito
93 chevy k1500: Cowboy

thanks -- already did the filters, including tank, but also bypassed the tank, swapped intake and return lines, no effect

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78 240d: Mona
81 240D: Lola
77 toyota chinook: Carlito
93 chevy k1500: Cowboy

thanks -- yes, much of what i've done on it so far came from kent's videos, and other sources -- i do have wrenches i made years ago, will check the valves, though po paid for a recent adjustment -- i do have a compression checker, as i've had diesels, domestic and german, for years, but it seems to have good power, just no acceleration -- yes, the injectors are on the list -- filters already done, air filter is new, oem

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78 240d: Mona
81 240D: Lola
77 toyota chinook: Carlito
93 chevy k1500: Cowboy

thanks for the quick replies -- does anyone suspect, as i do, cam belt stretch, injection pump timing? --

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78 240d: Mona
81 240D: Lola
77 toyota chinook: Carlito
93 chevy k1500: Cowboy

No cam belt.

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Jim

of course, sorry, i meant timing chain, not belt(another one of the reasons i drive a 123, and also the 77 toyota) -- back when i was rebuilding vw diesels, it was a belt, which made me nervous

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78 240d: Mona
81 240D: Lola
77 toyota chinook: Carlito
93 chevy k1500: Cowboy

How many miles? How much blowby? If the engine is up to spec. it should reach 86 mph in manual form and 83 in automatic version. I'm not suggesting that you do those speeds but, does it have anything left at 70?

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"Rudeness is a weak man's imitation of strength" - Eric Hoffer

139000 -- i was late for an appointment, was probably doing 75, and i wouldn't say that was at its max, but i don't usually drive that fast

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78 240d: Mona
81 240D: Lola
77 toyota chinook: Carlito
93 chevy k1500: Cowboy

wow, that little mileage?! -- and this came from the po with all its maintenance records, but for sure, its possible -- i'll definitely check chain stretch, ip timing, do compression test, before replacing the injectors -- of course, if the compression is way down, i'll do the rebuild, been there before

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78 240d: Mona
81 240D: Lola
77 toyota chinook: Carlito
93 chevy k1500: Cowboy

Yup...a now deceased Benz only indy listened to it and said it was too quiet and lacked a sharp clack at low rpm due to low compression. I did a rebuild using 0.5mm oversize pistons and the engine had a completely different sound when done i.e, the sharp pronounced clack was obvious and it ran very well.

Symptoms on mine were it was quiet, had blowby and wouldn't start in the NE winter.

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"Rudeness is a weak man's imitation of strength" - Eric Hoffer

very interesting, i'll have to remember that(at this time of life that means i cut and paste it into a text document in my mercedes folder)

anyway, i'd prefer to not do a rebuild, but if i have to, at least this is a car well worth doing it on, so i'll enjoy doing it -- though i'll need to find the right machine shop, probably in el paso -- and i have the other 240 to drive, so no rush -- rushing on a rebuild is when i can mess up

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78 240d: Mona
81 240D: Lola
77 toyota chinook: Carlito
93 chevy k1500: Cowboy