1970 250CE (european) Transmission H.E.L.P.

[JiveTurkey]

So several months ago I lucked into a 1970 250CE, originally sold in Italy. It was first registered in Saudi Arabia where it was bought by an American serviceman who took it with him to Germany, and finally to Tucson in 2006. I purchased it from him for $3,600 not knowing how rare these cars are in the U.S.
I've been fixing one little thing at a time on the car, but there are two big problems that are bugging the hell out of me. First, the transmission problem;
The car has the K4C 025 column shift automatic transmission. When driving, it usually starts out from a stoplight in second gear, it's in third by 30kph, and fourth by 50kph. When doing about 80-90kph the engine speed sounds quite high. The 250CE didn't come with a tach, so I can't give an RPM range. When in fourth gear, it doesn't matter where I have the throttle positioned, the car accelerates at the same steady dead slow pace, and will not downshift out of fourth until the car slows down to 20kph. Shifts aren't too hard, but they're not exactly soft either.

Oddly, if I move the column shift from D to S (next setting down) throttle response becomes much better. I drained the transmission fluid and replaced the filter last weekend hoping that would at least help a little. I'm suspecting problems with the control pressure rod (I think it's the balljointed rod on the drivers side of the trans) but I have no idea how to adjust it. Another possible problem might be the vacuum modulator, but I havent been able to find any instructions on how to locate it or service it. The blasted Haynes manual is really skimpy when it comes to transmissions.

Second pain in the ass problem.
I use Wilma (my name for my car) as a daily driver (thankfully I have a VW Rabbit as a second car in case I need to take the 250CE off the road.) and when I try to start her when she's hot the car will sometimes stutter and stall immediately after starting. If I open up the throttle a little bit while starting her she will run unevenly and have oil pressure between 1 and 2 on the guage. This doesn't happen all the time though. I'm using castrol 10-40 "high mileage" oil and it is filled to the appropriate level. If I start her and she starts to stutter and give low oil pressure I usually give her a little bit of gas and drive off. I can come to a stoplight 50 feet away from where I started the car though, and she will run fine (no missing, no low oil pressure) with oil pressure reading between 2 and 3 on the guage. I don't think the fan thats in front of the radiator works though. My cooling system doesn't leak and is filled to the apropriate level.
This one really has me confused.

If anyone has any ideas on how to help me out I would really appreciate them.

[Wodnek]

I am not sure if a 114 has a bowden cable, but if it does do a search on it here.
2nd posability is the modulator valve.

It really just sounds like the devices that control kickdown and shift points are the issues. The fact that it behaves better when you manualy shift reinforce my opinion.

I highly recomend getting the factory 2 volume 114/115 service manuals. A truely excellent resource with lots of closeups and pictures.

I had a 73 280CE euro spec car, when everything is right on them, they are like a rocket ship. View my photos and you can check it out.

[JiveTurkey]

Thanks for your lightning fast reply. Do you know where I could get one of the factory service manuals? I'm dying for closeups. The Haynes manual tries, but it's not sufficient sometimes.
I checked the kickdown switch, and it is properly adjusted and not blocked by the floor mat.
I'm seriously jealous of your 6.9 especially since it's a european one. I demand pics on completion of your restoration
I'm so hopelessly in love with my 250CE though, I drive it every day on a neat winding back road to my college and it's great fun to hustle through the turns with the tires moaning. I just wish I could fix that transmission issue so that I have the full potential of my engine available.

[ctaylor738]

There are several posts on how to adjust the bowden cable - try a Search. They are used on many models. Basically, with the throttle at rest, you want no slack in the cable.

[Wodnek]

Originally Posted by JiveTurkey

Thanks for your lightning fast reply. Do you know where I could get one of the factory service manuals? I'm dying for closeups. The Haynes manual tries, but it's not sufficient sometimes.
I checked the kickdown switch, and it is properly adjusted and not blocked by the floor mat.
.

The service manuals can be found almost all the time on ebay. Sometimes for $30 or under for the set. Sometimes you need to search several different ways. example: 114 manual, 115 manual, 114 service, 114 chassis, mercedes manual, etc. Using few words will get more results but sometimes too many.

If you absolutely can't find a set, i have a set I would let go for $75 shipped to your door, but you can do better.

[pch2021]

1. The car has a 3.92 rear axle. . They are geared low and they run hard. Don't worry about the high rpm's- they don't hurt the motor. I would, however, switch to Castrol 20-50. So issue 1. really isn't an issue.

2. The hard start: I estimate you fuel pump is not delivering enough fuel to the injection rail on a hot start to displace the hot, partly vaporized fuel in the fuel rail. This can be an issue on all cars equipped with Bosch D-jetronic, but is less likely on the sixes. My reccomendation would be to do a fuel volume delivery test. With pump warm, run the car's fuel pump and see how much fuel it delivers in thirty seconds. It needs to deliver atleast one litre warm.

[JiveTurkey]

You guys are fantastic!! It's the weekend now, so I'm going to check out my Vacuum Modulator and make sure it isn't leaking ATF. After reading the 10,000 other threads about the "bowden cable" I'm going to attempt to locate it and adjust it. I took some pictures last night.

If someone could put a red circle around the "bowden cable" I'd be very grateful.

[rs899]

I don't think that beast has a bowden cable. Maybe it has a bellcrank?

You might try calling Joergen or one of the guys at jie.com

[JiveTurkey]

I just love my 250CE. I didn't have any chance to try and adjust the shift points or shift sensetivity, but I did fix her right rear window today. Pillarless elegance has been achieved once again. Here's a random photo.

[JiveTurkey]

And here's a less blurry one. Anyone have any tips before I go back out and try to get the cooling fan that sits in front of the radiator to work?

[ctaylor738]

Here is the deleted post, minus the offensive language. I am re-posting it like this because it has good information. One my absolute rules in moderating this forum is that you don't trash people for providing answers that are to the best of their knowledge. You can correct them, but not trash them.

This is only the second time in almost ten years that I have had to delete a post.

CT

Modified version of deleted post follows

==========================================================
your car has no bowden cable.

Gear changes are modulated by a pressure control linkage on this gearbox and it may not have a vacuum modulator.[but if it does, it will be on the rear right side of the gearbox].
shortening the control linkage will quicken your shifts, but everyhting seems ok based on what you've said. These gearboxes inherently shift hard.
also, a kickdown solenoid, activated when the gas pedal is pressed to the floor, will control immediate downshift function based on accelration rate rather than speed. It should be verfied that the kickdown switch is delvering power. With the ignition on , locate the kickdown solenoid on the front right side of the gearbox. check for 12 volts at it with the accelerator pressed hard on the floor.

[JiveTurkey]

I'm really sorry if I offended anyone to the point where they would post something that has to be moderated. Did I do anything wrong?

[Wodnek]

Originally Posted by JiveTurkey

I'm really sorry if I offended anyone to the point where they would post something that has to be moderated. Did I do anything wrong?

Not that I could see! In 2004 I was new to Mercedes, though I started wrenching on cars when I was 14 in the 80s. I had many questions, and always got helpfull answers. Now I try to pay back by offering help when I can.

[ctaylor738]

No. Not at all. Your questions were good, and I think everyone appreciates a chance to get a look at what is a very rare model in the US.

[Mike D]

Originally Posted by JiveTurkey

I'm really sorry if I offended anyone to the point where they would post something that has to be moderated. Did I do anything wrong?

Yeah! You bought that great car before any of us could!