when you turn key,, no glow plug light,speedo starts to work,engine spins but will not start,before it would start and drive but all gauges speedo,oil,tach,fuel would rise and fall to zero, above problem started monday nite and by weds it would'nt start,it developed most of this while parked.

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1982 300sd (totalled) 1992 300se

Yep, without properly functioning glow plugs, the 603 probably won't start.

You need to determine if one, or more than one glow plug has failed. They are not all that easy to access below the intake manifold and are difficult to change without removing the manifold.

If the light is out, you probably have more than one bad plug, or the relay has failed. If the relay is the problem, it could be as simple as a bad 80 amp fuse beneath the cover of the relay. I'd replace this fuse, first, because it is cheap and easy to do.

Then, determine if the relay is operating properly. There should be 12V at the glow plugs for 35 seconds after the key is switched to the #2 position. Then, the relay opens and the voltage is cutoff. You can hear the relay operate at 35 seconds and the interior light will brighten slightly. If this is not happening, then the relay is not functioning and it should be replaced (provided previously mentioned fuse has already been changed).

If the relay is providing voltage to the plugs, then more than one plug is bad and the preferred solution is to remove the intake manifold to change all of them.

Thanks for the info,he had new glow plugs installed last month we will check the fuse and get back to you,

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1982 300sd (totalled) 1992 300se

Is the vac shut off lever down when you start? If so it should be in the up position o/w it isn't going too allow any fuel into the IP.
then,
If the glow plugs are getting power and still won't start its possible the Trap or Cat (which does yours have?) is plugged.
Loosening the nut on the front of the exhaust manifold (it was made for taking back pressure measurements) might allow it to start and idle. Try that its easy enough!

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'95 E320 Wagon my favorite road car. '99 E300D wolf in sheeps body, '87 300D Sportline suspension, '79 300TD w/ 617.952 engine at 367,750 and counting!

Brian Carlton you were absolutely right,it was the fuse,I called him and read your thread to him(he is not into computers)and he replaced the fuse, and all the crazy symtoms was corrected and it started and runs you saved him a trip to the shop....thank you.

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1982 300sd (totalled) 1992 300se

Excellent news.

Help is what we do here.