in my never ending quest to find out why i'm having hard & rough starts, i got a glow plug relay from deliveryvalve to find out if the loose pins in mine were causing my problems. let me describe what was happening with my original Beru relay:

turn the key, light on dash comes on, goes off anywhere from 2 seconds to 6 seconds depending on temp, relay clicks off (i listen for it) about 30 seconds later or so, and i start the car, it starts roughly and smokes a lot. or i'll do this cycle a couple more times to avoid the rough start issue. usually works.

now, when i put the "new" Mercedes Benz relay in:

turn the key, light on dash DOES NOT come on, relay clicks off in about 5 to 10 seconds, car starts up even worse than with the original relay.

why would it do this? why does the "new" relay not turn my dash light on and the old one does? is it possible that the Beru relay is not informing me of glow plug issues by turning the dash light on? could it have anything to do with the glow plug wire harness?

and, where does one find an "after glow" relay? i'm thinking that maybe if i just buy a brand new relay with the long after glow my problems might be fixed? didn't see one at fastland or allparts...

important info: i bought 5 new glow plugs this summer and reamed the holes with a reaming tool. i also pulled the plugs and tested them by hooking them up directly to the battery to see them glow. i also did the dieselgiant gp test proceedure outlined on the website. everything checked out fine, but i might do it all over again to be sure. ohms and electricity are not my strong point.... thanks!

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1985 300D - 1984 Euro 280E AMG Clone (SOLD) - 1978 280CE (SOLD) - 1983 300D (SOLD) - 1981 300D (SOLD)

That timer is defective.

Sounds to me like you original relay was working fine, have you checked you glow plugs. It sounds like you have one thats out.

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That is a possibility. Squabble Good thing I just gave it to you.


To do a quick and dirty check on the wiring. Take a simple light Circuit Tester and test each line for the plug that connects to the relay.

http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=30779


If it lights, the glow plug works. If it doesn't light, the glow plug does not work or the line is defective.

You can also test each connection of the relay to see if it goes on. But you'll need another person to turn the key.

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1983 123.133 California
- GreaseCar Veg System

no worries on the relay, i still owe you for your troubles, and all of this help!

can you go over this a little more in detail? where do you put each end of the tester?

EDIT: wait a minute, i actually clicked on the link you sent! so you just stick that in the plug for the relay pins?

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1985 300D - 1984 Euro 280E AMG Clone (SOLD) - 1978 280CE (SOLD) - 1983 300D (SOLD) - 1981 300D (SOLD)

Basically, get one of these...



Place the grounding clip on the positive terminal on the battery and then with the glow plug wire loom unplugged from the relay, touch the probe in each of the female sockets #1-5. If it lights up your good and most likely your glow plug on that particular cylinder is good. If it doesn't light up, then either your glow plug is bad or you have a wiring issue on that particular cylinder. And then it is easy to determine if it is the glow plug by just touching the probe on the terminal end of the glow plug directly. If it works then it is a wiring issue.

EDIT: ^^^ when testing glow plugs using this method, you must have the glow plug wiring harness unplugged from the relay. If not the tester will light up even though the glow plug is bad.

Now with the relay. You will put the grounding clip on a metal part of the engine and then test the ground by touching the prob to the positive terminal of the battery. Once you establish a good ground, then you take the probe
and touch it to the relay while someone turns the key. You can then determine if all 5 poles are getting power and are timing correctly.


I can take some pictures of this procedure if you like. But it will be a bit later.



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Attached Thumbnails

 

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1983 123.133 California
- GreaseCar Veg System

Basically yes. .. That is the quick and dirty (easy) way of checking glow plugs.



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1983 123.133 California
- GreaseCar Veg System

If the relay opens after 5-10 seconds, it's more of a certainty than a possibility.