Hi Guys,

How can i adjust the idle on my car. I feel like its low, and when it dips below a certain level, the car revs the engine up itself

Where is the idle adjust on the engine?

Thanks!

There is a numbered knob on the driver's side firewall, near the brake master cylinder. It will only affect the base idle speed (i.e. in the winter you can set it a bit higher) but the idle is controlled electronically. Most idle quirks on the 603 reported here are related to the overvoltage protection relay or ELR. Mine will occasionally "hang" up around 900 rpm and drop down very slowly, especially when it is very cold out ... rest of the time it's normal and it's so infrequent that I just ignore it (on the advice of my mechanic).

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1987 300D, arctic white/palomino--314,000 miles
1978 240D 4-speed, Euro Delivery, light ivory/bamboo--370,000 miles
2005 Jeep Liberty CRD Limited, light khaki/slate--140,000 miles
2018 Chevy Cruze diesel, 6-speed manual, satin steel metallic/kalahari--19,000 miles
1982 Peugeot 505 diesel, 4-speed manual, blue/blue, 130,000 miles
1995 S320, black/parchment--34,000 miles (Dad's car)

The ELR knob has to be lifted up to rotate. Higher number equals higher idle speed. There is also an adjustment on the injection pump, which should not be needed.

I have one '87 300D that also occasionally hangs at about 850 -900 RPM, then gradually drops down to normal. It seems to occur when/if I blip the accelerator. I also have not bothered with it, its not a constant occurance. But if someone figures out the cause I'll be all ears.

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'95 E320 Wagon my favorite road car. '99 E300D wolf in sheeps body, '87 300D Sportline suspension, '79 300TD w/ 617.952 engine at 367,750 and counting!

is there a idle adjust knob on a 93 300d with the om 602 engine.

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2011 e320 cdi (132,000) current
2005 Jeep CRD diesel--2.8L (138,000 miles) wrecked, insurance took
1993 Mercedes benz 300D 2.5 Turbo Frybrid powered. (336,000 miles) wrecked and sold as parts car
1990 Mercedes benz 300D 2.5 Turbo (170,000 miles) wrecked and sold as parts car

Check out my Frybrid Vegtable Oil Conversion at http://1990300dfrybridconversion.shutterfly.com/

I asjusted the Idle Knob and it worked it fixed the idle issue

Thanks guys


BTW.. new addition to the family 1990 E300 pickd it up for $2300. Good buy?