can anyone tell me how to modify my glow plug relay on my 300td to stay on longer like the relays they sell that stay on longer? i would hate to buy one if i could just modify mine, thanks

Do a search on purple wire. this has been hashed over before, don`t remember if it`s disconnected or not, but it leaves the relay on a little longer.


I found this thread www.peachparts.com/shopforum/showthread.php?t=237857

I searched, glow plug relay purple wire. there are others as well

Charlie

__________________
there were three HP ratings on the OM616...

1) Not much power
2) Even less power
3) Not nearly enough power!! 240D w/auto

Anyone that thinks a 240D is slow drives too fast.

80 240D Naturally Exasperated, 4-Spd 388k DD 150mph spedo 3:58 Diff

We are advised to NOT judge ALL Muslims by the actions of a few lunatics, but we are encouraged to judge ALL gun owners by the actions of a few lunatics. Funny how that works

Modifying the relay is easy. Under the cover you'll see a violet wire. This is the cranking signal from the keyswitch. If this wire is energized with 12V, the relay thinks the engine is still cranking and will keep the glow plugs energized.

So, simply put a toggle switch in the cabin to provide 12V to the terminal with the violet wire.

The problem is the driver. If he forgets to shutoff the switch (and he will), the plugs burnout in short order.

Could you use a heated rear window relay or some other timed relay to power the violet wire?

__________________

1981 300TD "The Green Lantern"
1980 300TD
1983 300D Euro "China Cat"

I'm sure you could. The power demand is not very high.

You could also use a pushbutton. Pretty difficult to burn out the plugs if you've got to leave your finger on the button.

Brian, what size is the wire? 16 gauge? Do you have a ballpark estimate on the amerage load of the wire? I want to buy a pushbutton that'll handle the load.

__________________
Regards,
Ian White

1995 E300 Diesel w124 OM606
2014 E550 w212 M278 biturbo

2001 BMW 740i E38 M62 (past)
1981 300SD w126 OM617 (past)

In the Pic below on the Terminal Block (if you have one) you see a White White Wire and a purple/Violet wire screwed together.
The White Wire would bring (+) current up from the Starter Solenoid when you have the Key in the start positoin.
So you would need to disconnect the Purple wire or cut up by the GP Realay connector becaue if send (+) current into the Purple wire it is going to start the Starter Cranking.

__________________
84 300D, 82 Volvo 244Gl Diesel

It's .75 mm. 16 gauge will be fine. I'd guess the amperage at NMT 5 amps. It's just a signal to the relay. It might be quite a bit less.

Alright, then I'll buy a small load button, thanks Brian-you are always so helpful. Thanks again!

__________________
Regards,
Ian White

1995 E300 Diesel w124 OM606
2014 E550 w212 M278 biturbo

2001 BMW 740i E38 M62 (past)
1981 300SD w126 OM617 (past)

Good point.

The circuit for the violet wire to the relay and the wire to the start solenoid is the same. Therefore, if you wish to use the pushbutton, the violet wire must be isolated from the rest of the vehicle.

those are all great ways to go but i thought you could modify the glow plug relay its self. ive seen these relays sold saying they keep the glow plugs on for up to 3 minutes.
so how do they do it?

The relay is controlled by a solid state device. It could, in theory, be programmed to operate for any period of time. In reality, if you want an afterglow timer, your best option is probably to buy one that works like you want it to.

so reading through this, disconnecting the purple wire at the terminal block would be better than cutting the wire at the GP relay. then run the wire to a switch on the dash with a red light to tell the driver it is on.

Maybe a 3 way switch?

A) Disconnecting the wire leaves the GP relay on longer, or it`s full duration of time.

B) position 2 wire is connected GP relay to terminal block, as original.

C) position 3 puts power to the wire to run plugs longer, with red light indicator. or a timed relay, or push button.


Charlie

__________________
there were three HP ratings on the OM616...

1) Not much power
2) Even less power
3) Not nearly enough power!! 240D w/auto

Anyone that thinks a 240D is slow drives too fast.

80 240D Naturally Exasperated, 4-Spd 388k DD 150mph spedo 3:58 Diff

We are advised to NOT judge ALL Muslims by the actions of a few lunatics, but we are encouraged to judge ALL gun owners by the actions of a few lunatics. Funny how that works