I was replacing the cracked brake fluid reservoir, and I noticed a loose cable. Looks like a flywheel sensor! Might explain why AC does not work either...

Checked around the bellhousing looking for a hole where I could see the starter gear, but there does not seem to be one on this engine/tranny. Judging by the parts the PO included in the deal, I think the engine/tranny came from something that used the TDC sensor on the harmonic balancer to feed the tach.

So now I have to figure out how to convert a one pulse per rotation to something that produces however many teeth there are on a ring gear per revolution.

Does anyone know how many teeth there are on a ring gear?

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1984 300TD

Is your '84 a California model?

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Jimmy L.
'05 Acura TL 6MT
2001 ML430 My Spare

Gone:
'95 E300 188K "Batmobile" Texas Unfriendly Black
'85 300TD 235K "The Wagon" Texas Friendly White
'80 240D 154K "China" Scar engine installed
'81 300TD 240K "Smash"
'80 240D 230K "The Squash"
'81 240D 293K"Scar" Rear ended harder than Elton John

My '85 has one of those where the engine and trans mate but it also has a pickup at the flywheel.

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Seth

1984 300D 225K
1985 300D Donor body
1985 300D Turbo 165K. Totaled. Donor Engine. It runs!!!
1980 300SD 311K My New Baby.
1979 BMW 633csi 62K+++? Dead odo

That is very likely. My 617.950 has the sensor on the harmonic balancer, but mine is non-op...I don't have that little tit sticking out of my sensor, perhaps it's been broken off.....hmmm...

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RIP: 80 300SD
RIP: 79 450SEL
2002 E430 4matic (212,000km)
2002 ML500 'sport'

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FACEBOOK: PANZER450

It's a federal.

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1984 300TD

Does anyone know wher on engines/trannys that use flywheel sensors the mounting point is supposed to be?

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1984 300TD

its near the back of the oil filter housing.... kind of hard to get at.

I could get you a picture.

Please do!!! Thanks.

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1984 300TD

Weird. I thought only 85's and '84 Cali. models had the sensor on the bell housing. They also have them on the front, but is for diagnostic purposes, not for tach.

BTW, my tach has never worked.....

__________________
Jimmy L.
'05 Acura TL 6MT
2001 ML430 My Spare

Gone:
'95 E300 188K "Batmobile" Texas Unfriendly Black
'85 300TD 235K "The Wagon" Texas Friendly White
'80 240D 154K "China" Scar engine installed
'81 300TD 240K "Smash"
'80 240D 230K "The Squash"
'81 240D 293K"Scar" Rear ended harder than Elton John

This one is definately a 1984 Model. Built August of 1983, actually!

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1984 300TD

Perusing the manual, this is an "Engine Speed Sensor" and it's supposed to be bolted on the left hand side of the engine near the edge. Of course, since the engine in my TD is an earlier model, the mounting points don't exist.

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1984 300TD

Here's a copy of the rotten picture that is in the manual:

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1984 300TD

sorry, this thread got by me... I will post a picture tonight when I get home.

What kind of diagnostics? Is that what the connector on the driver's (left) side inner fender is for? See attached picture. Anyone ever seen what is supposed to plug in there?

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"Buster" in the '95

Our all-Diesel family
1996 E300D (W210) . .338,000 miles Wife's car
2005 E320 CDI . . 113,000 miles My car
Santa Rosa population 176,762 (2022)
Total. . . . . . . . . . . . 627,762
"Oh lord won't you buy me a Mercedes Benz."
-- Janis Joplin, October 1, 1970

Jimmy is correct that only the '85 and '84 California models only have that sensor for the tach which is controlled by a computer. The '84 Federals only the sensor up front at the balancer and runs through the tach amplifier.

Jeremy, You would hook up an external tach to that attachment (it is actually where the "old" tach amplifier supposed to be) so you can see what is the RPM while under the hood.