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Marty, Mercedes Technician
Category: Mercedes
Satisfied Customers: 53904
Experience:  Bosch Certified Master Tech. Over 35 years experience.
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Why when I start off in my Automatic 1992 mercedes 400e do

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Why when I start off in my Automatic 1992 mercedes 400e do I have to let off the gas to get it to shift the first time after sitting still it shifts fine the rest of the time. If you dont let off the gas the rpm meter just keeps rising.
Hi Christopher, is this just a problem in the morning?

Customer: replied 7 years ago.
No it does it all the time, whenever you start off in order for it to shift you have to let off the gas and then it shifts and drives fine! If you dont let off the gas the rpm meter just keeps getting higher and higher. Whats wrong could it be as simply as the transmission fluid needing to be changed?
Customer: replied 7 years ago.
Why havent you answered my question? I need help!!! Please let me know whats wrong and what i need to do
Good morning Christopher, sorry I had family commitments last night and couldn't reply to you. Your transmission has an upshift delay system that delays the shifts when the car is cold. There is a cable that runs from your throttle linkage down to the transmission. The adjustment of that cable needs to be checked first and then the vehicle needs to be scanned for fault codes related to the upshift delay system. A malfunction in that system or a misadjusted cable may be giving you a delayed shift. That's where I would start with the problem. Let me know if you have any questions.



Customer: replied 7 years ago.
Thats fine, so if I adjust the cable and it still does it then that means I need to have it check for false codes? Where can I get this done at? About how much will the cost range to fix it? One more question, what is the easiest way to locate the cable from top or bottom of the motor? Will i be able to look down under the hood and find it or is it under the motor so I will need to look under it?
The cable attaches at the back of the motor. It's #11 in the diagram. You'll need to remove the air cleaner to access it. If you just disconnect the cable and drive the car and the transmission shifts quickly you can be pretty sure that the problem is in the upshift delay system. You'll need to take the car to a Mercedes specialist to diagnose the system.

Customer: replied 7 years ago.

So if when you unhook the cable and it shifts fine, then could the cable need replacing? I will let you know when i start working on it if i figure it out.




Disconnecting the cable gives you a starting point. If it shifts quickly with the cable unhooked then the adjustment should be checked. The upshift delay system involves the engine computer and a switching valve, some vacuum hoses and the cable. Next step would be to check the operation of the control system and the vacuum hoses.
Customer: replied 7 years ago.
Ok hmm speaking of vaccum hoses one of them was not in very good condition i noticed while we were working, would that be part of the problem? Also I have been trying to find a engine diagram for this car or either a wiring diagram is there anyway you could send me one?
Any broken vacuum hoses should be repaired as they can affect the shifting. The diagrams are split up in many different sections. What part of the car are you specifically looking for.
Customer: replied 7 years ago.
Umm preferably a diagram of the fuse box and the vaccum hoses. Also the battery in those 92 Mercedes 400e is weird its in a cover and I didnt see any positive and negative terminals like a regular battery. What about that? If you ever needed to replace the battery how would you replace it.
Ok, I've attached a handful of diagrams below. I'm not sure what you're seeing on the battery. You should have a normal style battery under the rear seat cushion.

Customer: replied 7 years ago.
Ok well maybe what I found was nothing to do with the battery. I was a bundle of wires together that ran to a large plug that plugged into an outlet right behind the battery I guess it could have been something to do with the fuses..... So if I unscrew the cover off the battery then it should be just like a normal battey?
Customer: replied 7 years ago.
Also one more question, looking at the diagrams is there several different fuse boxes as I have only found one and it was on the driver side of the car up under the hood close to the windshield.... Is there more that just that one? I looked inside the car but didnt see one.
There should only be the one main fuse box and a little small fuse holder in front of it for the a/c blower motor. On your battery are you looking under the rear seat?
Customer: replied 7 years ago.
You mean it inside the car under the seat?? What I found was under the hood. Does the rear seat just open up? Is that where the batteys located? Inside the car? Ok about the fuse boses
I believe on the 400E the battery is under the seat or in the trunk. On the 300E it was under the hood. Check the trunk first at the right side.
Customer: replied 7 years ago.
Ok i will check! Thanks so much!
Glad to help Chris :-)
Customer: replied 7 years ago.
Also what i found out with the a/c is that when you crank the car it all comes on, but it shuts off after like it running for 5min. After driving it to town and back i opened the hood and realized that the whole a/c line that runs from the compressor was froze over, after discussing it with this mechanic down the road he seems to think that the compressor clutch has gone out and thats why the compressor kicks off and the line freezes or either that the a/c is low on freeon and that the compressor kicks off so that it doesnt burn up the compressor. But I still have not gotten any air to blow out the vents........ I checked the fuses and they were all fine. Where is the regulator for the blower motor located and how do you tell if it is the problem or if I need a new blower motor?
What part of the a/c shuts off? Does the blower stop blowing?
Customer: replied 7 years ago.
Both I guess the fans and the compressor kick off but I havent gotten any air to blow out of the vents, unless you put it on auto fan which is where it blew a little bit while I was going down the road. After the all the a/c components under the hood kick off then i couldnt ever get them to come back on after pushing different buttons.
Ok, you should have a fan in the car regardless of whether the air, the heat or the vent button is pushed. As long as you have one of the three turned on it should blow some air. If your fan isn't blowing anything at all check the strip fuse in the little fuse box in front of the main fuse box.

Customer: replied 7 years ago.
I also have another Mercedes question this guy i helping has a 1990 Mercedes 190e and we are trying to get it running the last time it was cranked nothing was wrong with it, but that was when this guy that was working for him hooked the battery up backwards and crancked it. The man seeing what was happening ran over and quickly took the battery terminals off the battery and the car was turned off. Since then it hasnt cranked. It will try to turn over but we havent succeeded in getting it to crank. What do we need to do first, what is going to need checking and is it repairable?
First I would check the fuse in the overvoltage relay behind the battery. Next I would crank the motor and see if the fuel pump is running underneath the car and then check for ignition spark from the coil. You need to see what you're lacking, either spark or fuel or both.
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Customer: replied 7 years ago.

Thanks for all you help, you were right about the battery in my 400e when I opened the trunk there was a cover down on the right side and when I pulled off the cover there sat the battery. A HUGE battery! So thanks now that I have got things working on it I am trying to get the 190e fixed, so if i have any more questions I will be sure to use you!




You're welcome Christopher :-)