Hi all,

Last week I had my pre-glow time delay relay go out. A $50 pulled part got me going again. Today it seems like its dead again.

I'm thinking this isn't a coincidence.

Last time the fuse looked fine, but internally the relay seemed to fail. Haven't checked this one to see exactly what is wrong, but as before the glow plug light does not come on.

Recent electrical work involved replacing the left side cluster on the dash which controlled the oil warning light. The mechanic somehow shorted it but was able to fix it by running a seperate ground line somewhere. Not sure if that is related.

Anyone know what might be causing the relay to keep going out?

-M

Since there were no bites on this....

Is there a way to bypass the glow plug time delay relay and set up a manual switch to fire up the glow plugs in case of emergency? I'm assuming it would be up to the operator to decide how long to fire them up..

Are there any bad side effects besides brief rough idle if you don't run them long enough?


-M

Winter is coming! (even though its 100 degrees today)

I don't think there is any easy way of using a switch to bypass the time delay relay for the glow plugs. The glow plugs initially draw up to 80 amps during preglow and that tapers down as the glow plugs warm up. The actual glow plug relay on my 1987 300TDT is located on the drivers side fender and is a rectangular block mounted to the fender sheet metal. The G.P. relay varies the time delay before it shuts off the GP lamp in the instrument panel based upon the temperature of a sensor in the relay body. After the GP lamp shuts off, power is still applied to the glow plugs to for a total (including the GP lamp time) of roughly 35 seconds.

If the GP lamp is not lighting there can be multiple causes. Do a search for glow plug lamp and a bunch of stuff will come up.

As for running rough after startup due to no glow plugs, I don't think it will hurt anything in the long run other than harder starting and more smoke.

-Steve

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1987 300TDT smoke silver w/ burgundy leather interior
2000 VW Passat wagon indigo blue w/ beige leather interior
1985 Mustang SVO
1970 Chevrolet K10 fleetside, shortbed

3 sprays of ether into the air intake and it started up.. I guess a can will now stay in the trunk...I'll put it in an old ammo can just in case the spray can explodes. More shrapnel that way.

-M

I did it in my 1979 300sd. I put two relays in and they just kept draining the battery. There was some electrical issue I just couldn't solve. Soooo I bought a kit from mercedessorce... this one http://www.**************.com/store/item.php?item=Diesel%20Glow%20Plug%20Relay%20Manual%20Override%20Kit

installed it and have had no issues since. Don't see why it wouldn't work in your car. If you have a recurring glow plug relay issue that you don't have the time or money to fix it factory fresh.... I recommend this route.

Jon

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1984 Astral Grey 300TDT - The French Fry
1979 Yellow 300SD - The Pomme - SOLD
1985 Light Ivory 300DT - Fritz
1987 Anthracite Grey 300SDL - ?

don't do that anymore!



Can you hear the relay "CLICK" under the hood? Maybe the fuse died? Could just be sheer poor luck you received two bad relays too.

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I'm not a doctor, but I'll have a look.

'85 300SD 245k
'87 300SDL 251k
'90 300SEL 326k

Six others from BMW, GM, and Ford.

Liberty will not descend to a people; a people must raise themselves to liberty.[/IMG]

Is it bad to use ether to get it started on troublesome days?? (This is my first diesel).

No click... and the fuse looks intact.

Are you saying not to use ether or not to keep it in the trunk?

I called my mechanic and he said it was ok to use ether. It saved me a tow fee.

I've been told a few different things.....

1. use WD40 as starting fluid on a diesel

2. WD40 formula was changed a few years ago and in the process they removed its ability to help start your diesel...I'm assuming they took out the non-eco-friendly "good stuff".

3. Don't use ether if your glow plugs work, but its safe if they're not working.

Last time I tried WD40 for starting it worked, I heard that the main constituent in WD40 was Kerosene.
Ether washes off the oil on the cylinder walls. I destroyed a lawnmower from this and learned my lesson on a cheap engine.
If you have to use Ether, use it sparingly and infrequently.

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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!