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1990 Mercedes-Benz 560SEL Question: hesitation problem

 

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carolina560, Gasoline, Charlotte, NC, May 24, 2009, 10:56
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At times, when accelerating, the economy gauge will go up but the RPM's do not move and the car hesitates.Only lasts a couple secods and resolves it self. Fuel filters have been changed within the past 12 months.Any thoughts on issues?

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    May 25, 2009, 18:09
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     Master

    When was the last time you had your fuel injection system 'dialed in'? I used to work for Bosch and your car has a very sophisticated KE Jetronic System. There are some very important adjustments that need attending to every 30k Also the Oxygen sensors on this car are very touchy should be checked. ( They should be replaced every 60k) Most shops don't really know the German stuff. I would also do a fuel system pressure test while the car is under load. The KE Jetronic takes VERY POWERFUL fuel pumps and they could be getting weak. Also the Fuel Injection power relay can become intermittent. It should be replaced every 60k. Then look at your wires and cap and rotor. If they get worn, they can arc and cause a sudden lack of power. I have also replaced ignition coils on theses cars. They can burn up. Let me know how these inspections go.

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    Visitor, November 24, 2010, 18:29

    Hey buddy, i have another problem. If you don't mind will you please help me. I have 1989 Mercedes 560 SEL and in that car when i turn on heating system, it is working fine for first 8-10 min and after that it quit working and start blowing cold air. Will you please e-mail me the answer if you have on dharmeshdada1986@yahoo.com. I will really appreciate your help

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    Visitor, November 26, 2010, 17:47

    I find that a common problem on this vintage ( 1989 560 )Mercedes is the Climate Control Head, that goes into the dash. It wears out and then has no functionality from either the A/C or the Heating. The parts distributor where I buy my factory Mercedes parts can not keep these things in stock ( that should tell you something )
    It can be intermittent or fail when it gets hot etc .
    By no means is this a conclusive diagnosis, but I would start by inspecting that component. Hope this gives you an idea.

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    Visitor, January 29, 2012, 22:50
     Rookie

    I have a 1989 560sel. I really like the ride of the vehicle and the way it drives but I also have a very rough idle after the engine gets hot and then at that point when I start to take off from a stop it really seems to struggle until I get into second gear and after that it is fine. Also it does fine when I kick down the kick down switch in passing gear and it will bolt outta there nothin flat. The rough idle and take off is very annoying and it makes me want to go ahead and really give it the gas on the start to get past that rough spot. Of course I am using more gas like that and I really don't like driving the car that rough. I would really like to get this problem resolved. If this were any American car I would almost bet it was the timing advance but not being that familiar with how these things operate I am at a loss as to where to start in correcting the problem. Thanks in advance for your help.

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