Author Topic: love my mercedes  (Read 12593 times)

glort

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Re: love my mercedes
« Reply #15 on: January 10, 2014, 07:19:54 AM »
I thought the 1986-1993 3.5L 6 cylinder was still mechanically injected.  Aluminum head and other issues meant it wasn't NEARLY the engine that the earlier 4 and 5 cylinders were.
How come so often, newer engines are not as reliable and robust as the engines they replace?


[/quote]My NA 240D is so slow here at 4,700ft elevation, it almost feels like it's going backwards.
[/quote]

You could have those 4700ft below sea level and they would still feel like they were going backwards!

What made a HUGE improvement on my 300D was to wind the throttle stop screw right out.  I reset the throttle cable so I got full travel and the thing went Miles better.
Also check you are getting full throttle at the IP. A mate had a Low mileage wagon he was complaining about the sad performance. I reset the throttle linkage for him so the thing opened all the way up  unbeknownst to him and we didn't even get out out of his street before he said " What the hell have you done to it?"
Nothing other than set the throttle cable so it opened the IP all the way.  Later I took out the throttle limit screw and he couldn't believe the transformation.
Simple, cost free tuning that can make all the difference in the world.


You can also wind up the IP but I found that to be an impossible task to get the last screw out of the cover between the oil Filter and the block.  If you take off the oil filter housing it should be OK.  Every diesel seems to come very conservatively fueled ( and timed) from the factory so if you give them some more Juice, it makes a huge difference performance wise.

I turned the fuel up on my current truck and it made the thing want to jump out of it's skin.  I loved the power but so did my son and even more unfortunately, my learning to drive daughter.  I wound it back to above stock but still very reserved performance.  Still pulls up the steepest of hills on the highway in top gear at above legal speed, that's good enough for me.

BruceM

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Re: love my mercedes
« Reply #16 on: January 10, 2014, 05:07:14 PM »
Similar problems plague the pre-'86 turbo'd 300Ds.  There is an elevation compensator that goes out of adjustment over time, and opening the seal and re-adjusting that for just a bit of black smoke on full throttle acceleration yields amazingly improved performance.  Correcting for timing chain stretch and retiming the IP (offset keys are available) helps performance some, but cold starts more.  Turbo boost pressure can be adjusted slightly, also.  Re-adjusting the transmission downshift linkage also is often needed. They can often be brought back to quite lively performance. Valve lash is critical for cold starts.   




glort

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Re: love my mercedes
« Reply #17 on: January 10, 2014, 07:43:12 PM »
Valve lash is critical for cold starts.   


Same Friend I did the throttle cable adjustment for bought his Mrs a really nice red sedan.  Again lacking performance, the other tricks didn't help.  I did the valves on it for him with some bent spanners I made up and I thought something was wrong. I had about 7 goes at some of them and still couldn't get any gap on the things.  I thought it impossible they could be that tight as they would have to be near hanging permanently open. I remember 1 took 14 turns to get some clearance on. I didn't think that much adjustment was possible because it was far and away more than I had done on any of the numerous 617 engines I had done to that time.

Sure enough eventually they came good but it wasn't until we took the thing for a run I was confident there wasn't something plenty wrong .
He never complained about the starting of it but it sure made that thing come to life. I couldn't work out how the valves could be so tight and the thing still run at all.

 I remember despite being low mileage and excellent condition, that thing vibrated like no tomorrow. Eventually mate fixed it by changing all the rubber engine and gearbox mounts and the rubber cush drives.  Also had new self leveling suspension fitted in the rear which cost a bomb but he wanted it as original.
It did work nice.  Start the car and it leveled itself out then get 4 other blokes to jump in and it pumped itself back to sitting perfect again.

His Mrs was a vain so and so and didn't like being seen coming to church in an " Old car" so eventually nagged my mate into selling the W123 and getting her a W124.
She drove that a bit and whined about not being able to see out the back well enough so he got her an A series POS which barely fit the kids and groceries in but she finally seemed content with.

Think I would have kept the cars and got rid of the Mrs myself.

I remember at one stage, he couldn't start his car for a couple of months.
I went over to look at it and immediately noticed it was cranking slow. He hadn't picked up on it so I took the oversize battery even for a merc out of mine. Spun it up but still wouldn't start.  It was blowing white smoke when cranked but wouldn't light. I put methanol and LP gas down the intake but it still didn't want to know. I wondered if it were possible to flood a Diesel so pulled the 3 easy to get to glow plugs and cranked the thing over. It shot a stream of liquid out the first few cranks so when it stabilised, I put the GP's back in and the thing caught first couple of cranks.  Plenty of smoke out the exhaust then the other Cylinders fired shortly and the thing ran fine.
Apparently it was possible to flood a Diesel!

With new semi trailer size battery fitted, the thing would start in winter on SVO which mine would never come near doing.



 

deeiche

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Re: love my mercedes
« Reply #18 on: January 11, 2014, 03:38:06 PM »
SNIP
My NA 240D is so slow here at 4,700ft elevation, it almost feels like it's going backwards.
but going backwards is a New Mexico trait.   :D

BruceM

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Re: love my mercedes
« Reply #19 on: January 11, 2014, 08:53:15 PM »
240Ds are a bit slow at elevation, but I know a guy here at 5600ft who has one with over 600K miles on the original engine, and it still gets him to work and home every day, 45 mile round trip. I wouldn't mind a 240D as long as it had a manual transmission (rare and hard to find).

 Fortunately it's a rural road with 50mph posted speed limit, so he has little risk of being rear ended by a speeding semi. ;)