glow plug light staying on w210 e300

[lee1970]

hi all have a fault with glow plug light coming back on after start up,engine misfire & get a lot grey smoke out of it, have fitted 2 new set of glow plug just to be on the safe side but still the same, have 12 volts to each glow plug wires,so take it relays ok,
has anyone got an wireing digram, can only find one big eath from engine to gearbox.
is there ment to be any earth on cylinder head to earth glow plug.
any help on this would be great.

 

[Olivier]

Do you mean you fitted 12 glow plugs ( 2 sets?)
what brand?
Did you try each glow plug individually, direct to the battery, to be sure they all work?

 

[lee1970]

yes fitted two sets 12plugs,first set was baru, last set was ngk. tested all glow plug all ok, after fitting first set light was fine for about a month,would genuine make any diffrents.dose the the glow plug light act as a engine light?.
as far as i can rember the fault code was p1480 glow plug, only other fault was temp sender,have allso replaced that.

 

[Dieselman]

Are you sure the relay is delivering power to all the plugs under load. If a plug blows and shorts out, it blows the fusible link in the relay.

Beru or Bosch are OEM fitment and the best.

 

[Bobby Dazzler]

If I remember right there's relay or some other device which can lead to the lamp illuminating - it was referred to in a glow plug thread here on MBClub.

 

[Bobby Dazzler]

http://www.mbclub.co.uk/forums/engine/119584-v6-cdi-glow-plug-light-2.html

Post in that thread suggests it's possible to solder in some wire into the fuse as a cheap fix. No idea how much a replacement might be though.

 

[lee1970]

getting 12.5v at no 1 to 11.7v at no 6 with manifold off at glow plug end not looked at relay fuse, but would i still get 12v at glow plug end

 

[Olivier]

Sorry to tell you NGK are a waste of money. I had the same, changed them, a month later the light come on, I though it was the relay as the glows were new, I changed the relay, cost 75 quid, the light was still on, it was a glow that had burned, not the relay.
A while later I had to get another emergency set, the only glows I could get was the dreaded NGK, same story, 3 month later they failed one after another... Not a good buy... Beru are better, best I ever got were the bosch duraterm, tough cookies

On another hand, are you sure the relay is tightly plugged in? The connection pushed all the way?

 

[Dieselman]

getting 12.5v at no 1 to 11.7v at no 6 with manifold off at glow plug end not looked at relay fuse, but would i still get 12v at glow plug end

No, but have you measured all six separately, they are fed individually.

 

[SilverSaloon]

sounds to me like a simple matter of another glow plug failed. remember that 2 died, you only replaced 2..... but i suspect all 6 were the same age. its better in the long run IMHO to replace all 6 at the same time to save the hassle doing the job again a few months down the line when another fails.

just check the relay with a mulimeter as per this post to see which is failed:

Mercedes Diesel Glow Plug Repair

as with Olivier, NGK are carp. beru not much better In my experience.

i fitted bosch dueroterms in both my cars - the green car has had these in for just over 1 year now without any failing