Barry,

You could very well be correct. They do look similar, but I would have to check them to be sure. Does anyone know if both are indeed the same??? I can't seem to find a 'thermo time switch' for this car anywhere.

My tach works and then doesn't...swings all the way to 6,000 and then drops, even with two different tach adapters. Of course, used tach adapters could be faulty too and the tach worked fine before the long storage period.

I think I will order up some senders and see....Robert

__________________
Did you just pass my 740 at 200 kmh in a 300SD?????

1978 300SD 'Phil' - 1,315,853 Miles And Counting - 1, 317,885 as of 12/27/2012 - 1,333,000 as of 05/10/2013, 1,337,850 as of July 15, 2013, 1,339,000 as of August 13, 2013



100,000 miles since June 2005 Overhaul - Sold January 25th, 2014 After 1,344,246 Miles & 20 Years of Ownership

I wonder if the tachometer puts out an amplified pulse or does an internal conversion to constant dc? I do not have good manuals for these cars.

Either way a good monitoring point should be the output of the tach amplifier. Just observe if the output is the same when the tach is working and not working. I think a humble dc meter will read or average a pulse even. This is not a good ideal as I just re read that your tack is now never normal.

The prevelant problem although that is not always a good way to examine things has been an intermittent tach amp. More likely than an intermittent ground but anything is possible.

Before ordering up a sender for the glow plug relay if the part numbers are ellusive. You could read the indicated cold and warm resistance on both from another car.

Or as mentioned just take a jumper wire to the other sensor from the glow plug relay sensor line. I like to minumise buying parts just to replace good ones. If the glow plug relay cycle shortens up to normal you then probably have verification of your issue.

My glow plugs glowed a l-o-n-g time with both of them cold, but are on for just 1-2 seconds when outside temps are high...Robert

__________________
Did you just pass my 740 at 200 kmh in a 300SD?????

1978 300SD 'Phil' - 1,315,853 Miles And Counting - 1, 317,885 as of 12/27/2012 - 1,333,000 as of 05/10/2013, 1,337,850 as of July 15, 2013, 1,339,000 as of August 13, 2013



100,000 miles since June 2005 Overhaul - Sold January 25th, 2014 After 1,344,246 Miles & 20 Years of Ownership

Interesting problem....

This morning at 3:30am PST, I switched on the key to leave for work and noticed the tach was bouncing up and down. In unison to the movement of the needle, I could hear a distinct clicking from under the dash.

Any clues my Super-Benz Slueths?????

__________________
Did you just pass my 740 at 200 kmh in a 300SD?????

1978 300SD 'Phil' - 1,315,853 Miles And Counting - 1, 317,885 as of 12/27/2012 - 1,333,000 as of 05/10/2013, 1,337,850 as of July 15, 2013, 1,339,000 as of August 13, 2013



100,000 miles since June 2005 Overhaul - Sold January 25th, 2014 After 1,344,246 Miles & 20 Years of Ownership

Ok...

I pulled a sending unit that was originally in the glow plug circuit from another W116 car. It is marked 'BERU' and has a MBZ #0055422617. It is alos marked '6V-24V' and '120°C MAX.' It also bears the numbers '0824121001.'

My contact in the parts department at MBZ of Fresno advised the part number for the coolant temp sender is 005 542 1017 and his book listed a Glow Plug System Lamp Switch under part number 007 542 5717, but no better description of the device.

This morning my glow light didn't even come on, but this engine will start without glow plugs anyways. A short time later, I stopped at Starbucks and when I came out, the glow plug lamp came on for about 2 seconds.

What controls the glow time in this system????

Thanks for your input....Robert

__________________
Did you just pass my 740 at 200 kmh in a 300SD?????

1978 300SD 'Phil' - 1,315,853 Miles And Counting - 1, 317,885 as of 12/27/2012 - 1,333,000 as of 05/10/2013, 1,337,850 as of July 15, 2013, 1,339,000 as of August 13, 2013



100,000 miles since June 2005 Overhaul - Sold January 25th, 2014 After 1,344,246 Miles & 20 Years of Ownership

I still haven't found what is clicking in the passenger's side dash when the tach bounces...

__________________
Did you just pass my 740 at 200 kmh in a 300SD?????

1978 300SD 'Phil' - 1,315,853 Miles And Counting - 1, 317,885 as of 12/27/2012 - 1,333,000 as of 05/10/2013, 1,337,850 as of July 15, 2013, 1,339,000 as of August 13, 2013



100,000 miles since June 2005 Overhaul - Sold January 25th, 2014 After 1,344,246 Miles & 20 Years of Ownership

Glow time and glow light are controlled separately. Glow plug relay timer controls the time at the same rate every glow. You should be able to hear it click off sometime after about 20-30 seconds. Glow plug light duration is controlled by that temp sender and is completely independent of how long the glow plugs actually glow.
You could have a bad glow plug if the light didn't come on at all.

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1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

Changed the sending unit and the glow system is working great. Now I have to address the bouncing tach (and related clicking in the passenger's side of the cabin) and the bouncy fuel gauge...Robert

__________________
Did you just pass my 740 at 200 kmh in a 300SD?????

1978 300SD 'Phil' - 1,315,853 Miles And Counting - 1, 317,885 as of 12/27/2012 - 1,333,000 as of 05/10/2013, 1,337,850 as of July 15, 2013, 1,339,000 as of August 13, 2013



100,000 miles since June 2005 Overhaul - Sold January 25th, 2014 After 1,344,246 Miles & 20 Years of Ownership

I won't have any real time off until the weekend, at which time I need to find the source of my 'clicking' in the passenger's side of the cabin, that seems to be in unison with the tach's bouncy needle.

I refuled again this morning on my way to work and with the tire pressures set at the sideall spec of 44 psi, the car is delivering consistent 28.4 to 29.6 mpg figures.

Hoping that some free time and a swap to a 2.47:1 axle may break the 30 mpg barrier...Robert

__________________
Did you just pass my 740 at 200 kmh in a 300SD?????

1978 300SD 'Phil' - 1,315,853 Miles And Counting - 1, 317,885 as of 12/27/2012 - 1,333,000 as of 05/10/2013, 1,337,850 as of July 15, 2013, 1,339,000 as of August 13, 2013



100,000 miles since June 2005 Overhaul - Sold January 25th, 2014 After 1,344,246 Miles & 20 Years of Ownership

Ordered up some maintenance items, like tie rod assemblies, idler arm kit, shifter bushings, etc. and will address these on Friday. Dad and I are hoping to find out what is clicking in the passenger's side of the car in unison with the bouncy tachometer needle.

Funny thing....the fuel gauge stopped bouncing after I added two stroke pre-mix to the fuel!!!!!!!

__________________
Did you just pass my 740 at 200 kmh in a 300SD?????

1978 300SD 'Phil' - 1,315,853 Miles And Counting - 1, 317,885 as of 12/27/2012 - 1,333,000 as of 05/10/2013, 1,337,850 as of July 15, 2013, 1,339,000 as of August 13, 2013



100,000 miles since June 2005 Overhaul - Sold January 25th, 2014 After 1,344,246 Miles & 20 Years of Ownership

Can anything be done about the disrespect I am getting from the insects on my way to and from work????

Attached Thumbnails

   

__________________
Did you just pass my 740 at 200 kmh in a 300SD?????

1978 300SD 'Phil' - 1,315,853 Miles And Counting - 1, 317,885 as of 12/27/2012 - 1,333,000 as of 05/10/2013, 1,337,850 as of July 15, 2013, 1,339,000 as of August 13, 2013



100,000 miles since June 2005 Overhaul - Sold January 25th, 2014 After 1,344,246 Miles & 20 Years of Ownership

Greetings!!!!

Well, things are going well with the 116, but I still haven't fixed the 'bouncing' tach problem, neither have I found whatever is 'clicking' in the passenger's side footwell in perfect time to the bouncing tach needle....

How have all of you been????

__________________
Did you just pass my 740 at 200 kmh in a 300SD?????

1978 300SD 'Phil' - 1,315,853 Miles And Counting - 1, 317,885 as of 12/27/2012 - 1,333,000 as of 05/10/2013, 1,337,850 as of July 15, 2013, 1,339,000 as of August 13, 2013



100,000 miles since June 2005 Overhaul - Sold January 25th, 2014 After 1,344,246 Miles & 20 Years of Ownership

I'd pull the dash apart, and listen for the clicking and find out what it is.
maybe you sit in the passenger side, and have someone drive, until you trace what's clicking.

It's in the footwell on the passenger's side....

__________________
Did you just pass my 740 at 200 kmh in a 300SD?????

1978 300SD 'Phil' - 1,315,853 Miles And Counting - 1, 317,885 as of 12/27/2012 - 1,333,000 as of 05/10/2013, 1,337,850 as of July 15, 2013, 1,339,000 as of August 13, 2013



100,000 miles since June 2005 Overhaul - Sold January 25th, 2014 After 1,344,246 Miles & 20 Years of Ownership

yeah, so pull the dash panels out and stick you head down there and have someone drive around until you hear the noise and pinpoint it.