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  #1  
Old 02-10-2007, 01:21 PM
JamesDean's Avatar
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Glow Plug Idiot Light Question

good afternoon everyone,

so last night i started up the SD and I noticed that the glow plug idiot light didnt stay on as long as it usually does. It stayed on for maybe one-two seconds if not less. The SD had a rough time starting, I had to drop the pedal to the floor to keep it from choking out...i cant remember if the idiot light means the plugs are on when it is on and off when it is off or if its just a timed light...im forgetting how the glow plugs exactly work in the SD

So does this mean anything bad/good/otherwise?

Thanks,

Kris

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  #2  
Old 02-10-2007, 01:41 PM
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whiew, at least it's not a oil question...
the dash gp light, is just an indicator that the plugs are mostly working. it has no bearing on how long the plugs are energized. properly working the light should indicate the absolute minimum glow time. when it's cold, I let the gp's run the full time they can. if you listen you can hear the relay click when it is done.
John
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  #3  
Old 02-10-2007, 03:22 PM
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Sounds like you may have a bad GP or two. dieselgiant.com has a DIY GP troubleshooting guide.

The light is just like John says.
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Old 02-10-2007, 03:53 PM
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Agree with BIOdiesel, check GP's with OHM meter. On my SD the light would not come on at all, found out one plug was bad, replaced, solved.
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  #5  
Old 02-10-2007, 07:15 PM
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Quote:
Originally Posted by toomany MBZ View Post
Agree with BIOdiesel, check GP's with OHM meter. On my SD the light would not come on at all, found out one plug was bad, replaced, solved.
ok guys heres what i did and what happend:

1) i verified that the relay was making noise, it did indeed click when the key was turned

2) the fuse was in good condition on the relay itself

3) i checked all GP's and they all had nearly the same value of 00.9 ohm (is that a good reading?)

i am unsure of where to go from here, it could be as simple as the light in the dash is out...i dont really feel/know how to pull a 126 dash..

thanks everyone
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  #6  
Old 02-10-2007, 08:25 PM
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Quote:
Originally Posted by JamesDean View Post
ok guys heres what i did and what happend:

1) i verified that the relay was making noise, it did indeed click when the key was turned

2) the fuse was in good condition on the relay itself

3) i checked all GP's and they all had nearly the same value of 00.9 ohm (is that a good reading?)

i am unsure of where to go from here, it could be as simple as the light in the dash is out...i dont really feel/know how to pull a 126 dash..

thanks everyone
If all the glow plugs are getting 12V and you properly verified .9 ohms on all of them, then it's unlikely that it's a glow plug issue.

However, your poor starting capability seems to point in the direction of a problem with the glow plugs.

Therefore, either your observations are incorrect or your testing procedure is incorrect.

The glow plug light is providing you with a clue that there is a glow plug issue. The failure to offer a clean start is also supporting that diagnosis.
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  #7  
Old 02-10-2007, 09:55 PM
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Check the voltage to each plug to make sure they are getting 12V, then also check the resistance of the wires to the GPs. Pull the top of the relay off, then pull the plug off that has the wires to the plugs. Then test each wire for resistance.
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  #8  
Old 02-11-2007, 05:15 PM
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.9 ohms, GOOD reading. If light is activating regardless of how long, no need to pull dash, not difficult yet time consuming. Should I start a sentence with if? English majors, this is why you went to school. Can guess, {were your superhero name to be Flash, would help} yet don't know how to check if getting 12v. If not, bad connections at GPs?
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  #9  
Old 02-11-2007, 07:20 PM
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Its been my experience that sometimes a plug will give you a good ohm reading, like 0.9, but will still fail to glow when removed from the engine and hooked up to the battery with jumper cables.
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  #10  
Old 02-11-2007, 08:00 PM
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Quote:
Originally Posted by sailor15015 View Post
Its been my experience that sometimes a plug will give you a good ohm reading, like 0.9, but will still fail to glow when removed from the engine and hooked up to the battery with jumper cables.
Pulling the plugs and putting jumper cables on them has always worked for me. I wouldn't trust any other test.

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