85 300d 180k miles
had no warmup light. hard starting.
replaced the glowplugs this am. checked fuse in glowpug "box" ok.
lamp is ok in cluster.
what else should i check?

thanks
cliff

Maybe your glow plug relay is bad or the bulb for the light is out

how might i check the relay?

Engine Electrical:
http://www.peachparts.com/shopforum/showthread.php?t=142401





Have a great day.

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1985 300SD
1983 300D
1984 190D
2003 Volvo V70
2002 Honda Civic

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Also get yourself a cheap volt-ohm-meter [VOM] IF you don't already have one and use it to check the voltage at the GP while you go through the start/warmup cycle. You should see battery or near battery voltage at each connector during the warmup cycle and regardless as to what the amber dash light is doing or not doing, you should see battery voltage at the GPs for longer than the amber light normally stays on... about 35 to 45 seconds.

Complete your signature with the basic car info... something like that you see below.
Regards

I was going to make a post about GPs as well, so I'll hi jack, along this thread. I'm looking to find out the operation of the GP timer, I've tested mine and I have power at the plugs untill the engine starts then the GP looses it power, keep in mind this engine is in a toyota 4x4 and I wired in the MB GP timer, IIRC there were only a couple of wires, battery power(larger wire) a signal wire from the starter and one from the ignition, and a ground (I think). I remember pouring over the wiring diagram. But I dont believe it it normal for the power to go out, as soon as I hit the starter... engine starts OK, just runs a little rough for a few seconds
BTW its an 85 300sd

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91 Toyota 4Runner powered by a 84 300SD driveline. Truck has 4:56 gearing on 31 AT tires, 2.5inch exhaust. Pillar mounted exhaust pyro and Boost gauges

I believe I remember others saying in this diesel FORUM saying that the earlier OEM GP relays had NO post-start warm-up cycle and that one of the things you get with the new Bosch "Fast" relay+GP kits is such a post-start continuance of power to the GPs... thus the improvement.

Apparently Bosch does not make their "Fast" relay upgrade for the 1980(s) model so IF/WHEN I face a relay problem that results in a relay replacement, I'll probably go with a simple relay that uses a spring-loaded push-button or rocker switch that let's the driver decide how long to power the GPs!
Regards,

pulled relay from 83 and installed in 85 and starts right up.

thanks for all the help.

cliff

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1983 300d~250k Sold
1985 300d~185k
1999 Volvo V70 wagen 109k
2001 Dodge Ram 1500 78k

That's perfectly normal. As soon as the key is turned to position III, the violet wire signals the relay to shutdown. Older engines can run a bit rough during first 15 seconds after startup.

There is an afterglow relay kit available that has a new relay and a set of plugs designed for longer duration and the kit will allow the plugs to remain on for a specific period of time after the engine starts. It's a bit pricey at $160. or so, but, some folks like the results.

Thanks!
So.... if I interupt the violet wire signal, maybe with a push button (normally closed type) I could keep the plugs on for a couple of seconds while the engine runs, then release the switch,(turning the GP's off) something I could use on the really COLD days......

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91 Toyota 4Runner powered by a 84 300SD driveline. Truck has 4:56 gearing on 31 AT tires, 2.5inch exhaust. Pillar mounted exhaust pyro and Boost gauges

I had a hard start the other day, actually the wife did, and it was not cold maybe +5C. So if my timer is working properly, maybe I'll throw some new GP's in. (after confirming resistance)

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91 Toyota 4Runner powered by a 84 300SD driveline. Truck has 4:56 gearing on 31 AT tires, 2.5inch exhaust. Pillar mounted exhaust pyro and Boost gauges

... that reads:
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91 Toyota 4Runner powered by a 84 300SD driveline. Truck has 4:56 gearing on 31 AT tires, 2.5inch exhaust. Pillar mounted exhaust pyro and Boost gauges

... so I just have ask - Are you a " Greaser "... one who uses alternative fuels ?

You'll have to check the schematic for the violet wire. IIRC, the wire goes open when the switch it turned to the start position. So, you may need an NO pushbutton to keep the relay thinking that it's still got the violet wire connected.