My new 81 SD's idle is too high around 1000 rpms. I checked Haynes manual and it stated.

"On 1980 and later models idel speed adjustments require the use of special tools and techniques and the job should be left to the dealer". Hmmmmmmmm?????


William Rogers.......

There should be a set screw that the linkage rests against on the side of the IP closest to the head.

Sixto
95 S420
87 300SDL

There is no set screw I shorten (screwed in) the rod that goes to the bottom of the ip pump it droped the idle but still not sure if that is the correct method...........

William Rogers..........

This is an image from the manual. It shows a set screw just inboard of the ALDA. How strange that your car doesn't allow such an adjustment.

Sixto
95 S420
87 300SDL

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sixto, I tryed turning number 3 in your photo and it made no change, if I push down on number 2 that is connected to the vacuum dump unit it did slow the idle so maybe thats it. I'm not sure I got number 3 back in the same position ,what is it's function? thanks a lot...........

William Rogers.......

Number 3 is a lock nut, it's number 4 that you turn...

what is the suggested way to loosen the tightening nut? I was hoping that the injector line spline wrench would work but NOoooo... too big!

__________________
Mark Herzig
1995 E300D 153K
1985 300D 142K (sold)
1979 450SL 122 miles (sold)
1992 500E 127K (sold)
1987 300SDL 132K (sold)
1986 300E 161K (sold)

I turned 4 but it changed when I tightened the lock nut with a deep socket, I have been working on two cars a once so will fiddle with idle tomorrow............

William Rogers.......

When I got my car the idle was too low. I adjusted it to spec by popping off the rod shown at 2, then loosening the lock nut (3 in the picture above) with a crow's foot wrench on my ratchet - I want to say it took a 13 mm crow's foot, but I can't recall. Once the idle was correct I loosen the lock nut and ball cup end of the rod so that it would fit back over comfortably. Tighten everything up - done. CAUTION - you MUST make sure that you adjust the rod to match the new idle setting. It the rod is too short your accelerator can stick open leading to some rather exciting driving. Don't ask me how I know.

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Tjohn

82 300 SD
77 450 SL (gone)

tjohn (or anyone else)

if i want my idle to go up just a hair,

after i adjust the screw, do i lengthen the rod or make it shorter?

thanks!