1985 Euro 300TD
Can someone tell me where to look?
I'd like to add a tach. It may be more complicated that I'm thinking, and it may be a while from now, but if I know it can be done, I'll put it on the list.
It was easy to do on my gas powered '86 4Runner, so it must be easy to do on the diesel benz, right?
Thanks,
-Geoff

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1985 300TD-euro 352,000 mi
1974 240D (1?)52,000 mi - has a new home now

I'm not sure if you have one or not, but many here have longed for a tach, I bought a tinytach and it worked fine for a while, but it died in less than a year, I think it had a 30 day warrenty... pretty lame.

I do not have a crank sensor, so I'm going to install a tach that is driven from the alternator... My boat has the same setup, I just have to do the necessary homework to figger out how to do it from my benz alternator.

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Cheers,
Robert

If your 85 has cruise control, then you should have a crank sensor. There is a magnet on the harmonic balancer assy and there should be a long grey multi-wire with a bullet shape thingy on the end pointed at it.

I do have cruise control...not working but
thats not the issue...so I'll look for a gray wire coming from the lower portion of the engine block then? With a bullet on the end? I'll start poking around...
Thanks,
-Geoff

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1985 300TD-euro 352,000 mi
1974 240D (1?)52,000 mi - has a new home now

I looked on my CD, there is a wire running down from the amp to... I can't tell, except it's near the crank shaft, just to the drivers side and below of timing tab. However, a friend has a 123 Euro, and he tells me there is sensor on his. He has non-working cruise as well, albeit a servo unit, it's a '79. You'll need a different dash, at least the one gauge, bracket, said amp, plug for amp with wire to sensor, plug for gauge. Most of which you may obtain at a pick'n'pull, if available. I think the only new part you need would be the amp itself as they are prone to failure.

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83 SD

84 CD

The cruise control is unrelated to the engine speed - but to ground speed and a sensor on the speedometer cable or speedometer. I'm not sure if non-turbo engines have the speed sensor on the bracket on the left side of the damper (that is used to hold either the engine speed sensor on tach equipped cars) or simply have the bracket that will hold the diagnostic equipment sensor.

I expect you will need the sensor, and you will need the amplifier assembly, wiring for it and the correct tach assembly.

Most 84 and later diesels with tachs used a flywheel sensor and a different tach/amp assembly rather than the damper sensor but the 123/126s with 617 engines still had the sensor mounted beside the damper so that factory diagnostic equipment (that depended on the damper sensor) could be attached.

Marshall