Non-starting W202 diesel

[MattyH]

As of yesterday, the diesel preheat/glowplugs light (is this the right terminology?) is ceased to come on when I put the key in the ignition of my 1996 250D W202 automatic and turn it to the first click. Nor will the engine fire when starter motor is swung
Battery is strong and engine turns over lustily.
Possible red-herring to mention. As of this week, car has cut out when climbing and turning hard right on a sharp incline – this is first thing in the morning, before operating temp has been reached. After car is rolled down to a flat area, starts after some cranking.
Is there a relay or something I should be inspecting as a first port of call? And if so which one?
Advice, suggestions gratefully accepted.
Thanks,
Matthew

 

[Blobcat]

Glow plug relay?

 

[MattyH]

Yes. I believe so. How do I identify and test it?

 

[bladecrazy]

on my 124 its on the right hand side on the inner wing, a small black box with wires going to your glow plugs.

 

[Doug1234]

Relay as above and keep the fuel tank at least 50% full at all times, it has what are called saddle tanks and the fuel is meant to even itself out but it does mot and the engine will run out of fuel / not start. The car cutting out on sharp incline and starting on the flat ground points to this… so for now just keep tank topped up.

 

[MattyH]

on my 124 its on the right hand side on the inner wing, a small black box with wires going to your glow plugs.

Thanks. The weather is good today and I am going to hunt for it.

 

[MattyH]

Relay as above and keep the fuel tank at least 50% full at all times, it has what are called saddle tanks and the fuel is meant to even itself out but it does mot and the engine will run out of fuel / not start. The car cutting out on sharp incline and starting on the flat ground points to this… so for now just keep tank topped up.

That makes a lot of sense. Now that I think of it the car was deep into reserve.

 

[MattyH]

Thanks for the pointers, chaps.
Relay was under the washer container.
Inner wing, right-hand side of the engine bay (looking in from the front; passenger side in other words on this RHD car).
Multimetre recorded 12.7V at the main terminal. No voltage at any of the five big pins (believe these power the plugs). And a reading of 0.4v at one of the five small (control side?) pins. No reading at the other small pins.
So I did what I should have done to start with (blush, apologies) checked the fuses carefully.
Fuse no. 30 blown. According to the key on the inside of the fuse cover box, this fuse is for 'engine components, stop lamps (tempomat/cruise control)'. Should have a 20A fuse fitted but the blown fuse is 25A (as I recall --without going back to garage to double check).
Substituted blown fuse with a spare and car started immediately.
Will buy some more fuses and keep an eye on the circuit.