zero to 60 takes 18 seconds
 

1991 350SDL - Just wondering what acceleration rate others are getting. It takes 18 seconds to reach 60 mph at full throttle. Has anyone else checked theirs?

Has the previous owner swapped in a 240D engine?

that seems really slow for that motor...

That's definitely too slow. You should be able to do something around 12 seconds... the 240D did 0-60 in 19 seconds out of the factory, and that was with 67 HP :eek:!

Have you checked your filters?

Agree; something like 12 seconds.

Remove the ALDA and try it again.

It comes off the line very fast, then stays in second and third gear too long before shifting. zero to 30 comes really quick, then between 30 and 60 is not quick to come. Thanks, I will adjust or remove the ALDA and try again.

Staying in gear "too long" generally is a good thing, most peoples 722.3 acceleration issue is they stack shifts and get into 3rd way too quickly and you're tugging your way through third not getting much done.

3.5s have a lower redline than 3.0s, does it shift around 4,200 rpms? That's when it should shift.

It shifts at 3800 rpms. Get's about zero to 50 in 12 seconds, then another 6 to get the other 10 mph. I will adjust the ALDA and report back.

Vacuum leak was the culprit!!
 

Sorry to take so long to post back the results. I found a leak in the vacuum line going to the ALDA. Ran it once and it took 13 seconds. I'm happy with that.

Soundsin the ball park though a few small improvements might shave a second off, if that is important to you.

I'm very happy with the performance I now have. I never run it that hard. :)

How many American-made cars will even go 60mph after 335,000 miles and 24 years?

11.4 sec according to the factory.
http://oudemercedesbrochures.nl/Imag...SA1990/010.jpg

If the car does not perform to factory standards by a long shot - as you had beginning the thread- the first suspects are out of adjustment/broken mechanical items and things you maintain. Change/check all filters and fluids. Check/adjust all throttle linkage and transmission settings. Check the brakes and tire air pressure. Don't start modifying the cars engine because it does not work as designed if it's not able to do so because it needs fresh fluids/filters and a "tune up".
Sounds like your inspection found the tune up item which was needing attention that solved the problem.