Very HIGH RPM= HIGH MPG

roach_juts

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hello

i am wondering that my 1990 wagon has a high RPM, when the car is at idle the RPM is around 500 to 600 rpm which looks normal , but when i am driving it around 60mph the RPM is at 3K RPM , when i speed up to 80 MPH the RPm will me 4k RPM .. this seems not to be normal , because my other w124 if i run it at 80MHp the rpm is 3K RPM....

i did a change oil already, with ( oil additives)
added fuel injector clean & even sprayed the carb & injector
but nothing changed

i am thinking changing the distributor, rotor, fuel filter & O2 sensor
i hope this will help the RPM go down to normal

ANY SUGGESTION & ADVICE ??

thank
 

Bolide

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Your Mercedes
BMW 525 Diesel Touring
400 rpm at 80 mph is right for most of the smaller-engined W124 estates. Doing the things you propose won't help

The only possible problem is that the car is not going into 4th. If that was the case, though, it'd be pulling even more revs than it is now

It's just a characteristic of the car

Nick Froome
www.w124.co.uk
 

brandwooddixon

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Your Mercedes
CL500 Bluefficency 2012
You don't state what car you have, engine size or even if it's an automatic.

High rpm whilst driving wont be anything to do with the engine, it will only relate to gearing and the gearbox.

As Nick says, if it's a small engined estate then it will have lower gearing and thus rev higher than a larger engined car. This is all down to the gear ratios.

If car is an automatic and it has a similar sized engine to your previous car then it is possible that it is not switching to the highest gear or there is some torque convertor slip.

I believe that some of the user manuals state what rpm to expect for given speeds and gears.
 

television

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2002 SL500, 216 CL500, all fully loaded
I do have a table for the given RPM at all speeds but the engine size is not mentioned here
 
OP
R

roach_juts

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  • Thread Starter
  • Thread starter
  • #5
ohh i for got the engine is a M103 & the car is a 300te 1990 model
 

Seeker_UK

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I would say for a 4-speed that sounds about right.

300TEs are not known for their fuel economy. ;)
 
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