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  #1  
Old 09-09-2009, 06:36 PM
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Glow Plug / Ignition Problem (Suddenly No Glow Plug Action) >> 1979, 300D

This morning I was suddenly not able to start my car for work. When I clicked the key over to get the glow position, the normal dash-light indicator went on, but then quickly went out.... after that I was not able to get the car started, although I seemed to have plenty of juikce in the batter to spin the engine and churn it.

The week prior to this, I noticed that my little buzzer-speaker sound that happens when I turn the igniction was sounding kind of funny... kind of a feeble warbling sound.... i kind of thought that maybe the batter was getting low, but now wonder if it might be related to this new glow-plug problem.

Can anybody help me with the proper steps to diagnose this problem. Seems like my "glow plug relay" may have gone out, or perhaps a glow plug itself? A failure in one glow plug means that the whole series circuit will not work right? Where does one find the "glow plug relay"...? How could I eliminate if the problem is in the key-switch also? Any tips would be greatly appreciated...

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  #2  
Old 09-09-2009, 07:06 PM
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Go to www.dieselgiant.com and follow the glow plug troubleshooting sequence.
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1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13
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  #3  
Old 09-09-2009, 08:19 PM
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Your 79 300D has the series style plug system. One bad plug and the whole system won't glow.

Follow the write up and check your plugs for bad ones. You might benefit from upgrading to the fast style glow plugs wired in parallel instead of fixing it to original configuration.
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Old 09-09-2009, 08:58 PM
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Quote:
Originally Posted by MBeige View Post
You might benefit from upgrading to the fast style glow plugs wired in parallel instead of fixing it to original configuration.
I highly recommend updating the glow plugs. I replaced my old loop-style glow plugs in my 79 300D periodically so figured they were working just fine. I converted to the fast style glow plugs about a month ago out of curiosity and it is a world of difference. The 79 300D starts like an absolute champ now.
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84 300D 255K "Mr B" ("Mr Becker")
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  #5  
Old 09-09-2009, 09:29 PM
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Thanks, found glow plug relay and resistor strip.

So, with the aid of that dieselgiant website guide, I found the relay and strip-resistor on my parts car. I'll take those parts and go back to my running car and swap out and check things. Seems like with the help of that guide and the spare parts I should be able to get back on the road.

Thanks All.
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  #6  
Old 09-09-2009, 11:07 PM
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Ooops, I didn't notice it was a 79 300d. I don't think dieselgiant covers testing of series plugs does he? You can check series plugs visually by looking at the heavy looped wires with the key in the glow position. If those wires don't glow, there's a bad plug somewhere.
Does your parts car also have loop style glow plugs. OE pencil plugs and loop plugs are not interchangeable. You can replace the loop style with pencil plugs designed for the loop plug holes, and then creating your own jumper wires to go from plug to plug.
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1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13
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  #7  
Old 09-09-2009, 11:43 PM
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Hello, not to jack this thread but I have a gp question. I'm still just playing with my 83 300d but noticed it was missing on start up so I did GP maintenance and found #5 burned out. I replaced it and no more missing on start-up. But I would say it turns over once or twice before it fires. Granted thats not bad but I think it could/should be better. Do the plugs only glow as long as the dash light is on or what??? I live in Tucson, AZ and its been 100 degrees all summer. I do't know how the circuit for the Gp's work as far as glow time so I thought I would ask. Thanks
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  #8  
Old 09-09-2009, 11:56 PM
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Glow light duration and actual glow duration are independent of each other. Glow light duration is determined by a temperature sensor, glow duration is fixed length of time determined by a timer, typically 30-50 seconds long. You can hear the glow relay click off at the end of its timed cycle.
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1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13
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  #9  
Old 09-09-2009, 11:58 PM
Craig
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On your 300D the GPs will actually glow for about 40 seconds (or until you crank the starter). The light is just an indicator to let you know approximately how long you should wait. Next time, wait an extra 5 seconds after the light and see it it starts quicker.

Mine usually starts instantly when the light goes out (less than one crank). If the GPs are in good shape you might have something else wrong (valve adjustment, air leak in a fuel line, etc).
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  #10  
Old 09-10-2009, 12:03 AM
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Quote:
Originally Posted by Craig View Post
(or until you crank the starter). .
Actually when you release the key after engaging the starter. (there was a thread on this topic in the not too distant past.)
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1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13
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  #11  
Old 09-10-2009, 12:06 AM
Craig
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Really, I always thought it cut off when you started to crank? I didn't know that.

I have the post-glow relay in my 300D, so it keeps going for about 3 minutes after the start. I'm assuming that DocSarvis has the original relay.
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  #12  
Old 09-10-2009, 12:14 AM
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Quote:
Originally Posted by Craig View Post
Really, I always thought it cut off when you started to crank? I didn't know that.

I have the post-glow relay in my 300D, so it keeps going for about 3 minutes after the start. I'm assuming that DocSarvis has the original relay.
I too dwelt in ignorance until that thread.
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1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13
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  #13  
Old 09-10-2009, 07:03 AM
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where did you get a "post-glow" relay? i'm still having the same starting troubles from a previous thread (Rough Starting / Rough Idle...Ongoing Problem - Ideas please! (yes i've searched....)) and i think it's getting worse. that relay might help...
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1985 300D - 1984 Euro 280E AMG Clone (SOLD) - 1978 280CE (SOLD) - 1983 300D (SOLD) - 1981 300D (SOLD)
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  #14  
Old 09-10-2009, 08:52 AM
Craig
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Quote:
Originally Posted by Squabble View Post
where did you get a "post-glow" relay? i'm still having the same starting troubles from a previous thread (Rough Starting / Rough Idle...Ongoing Problem - Ideas please! (yes i've searched....)) and i think it's getting worse. that relay might help...

I think I bought mine from Phil, but it's been a few years. Give Phil a call and see if he has them available. I believe they came in a "kit" that includes 4 GPs (for a 240D), but will will also work in a 300D.

Note, they do help the car warm up, but they are harder on the battery and GPs if you make lots of short trips.

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