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#1
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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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Cruise Control not working? Send me PM or email (jamesdean59@gmail.com). I might be able to help out. Check here for compatibility, diagnostics, and availability! (4/11/2020: Hi Everyone! I am still taking orders and replying to emails/PMs/etc, I appreciate your patience in these crazy times. Stay safe and healthy!) 82 300SD 145k 89 420SEL 210k 89 560SEL 118k 90 300SE 262k RIP 5/25/2010 90 560SEL 154k 91 300D 2.5 Turbo. 241k 93 190E 3.0 235k 93 300E 195k |
#2
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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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John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread "as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do! My drivers: 1987 190D 2.5Turbo 1987 190D 2.5Turbo 1987 190D 2.5-5SPEED!!! 1987 300TD 1987 300TD 1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere! |
#3
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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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Andrew '04 Jetta TDI Wagon '82 300TD ~ Winnie ~ Sold '77 300D ~ Sold
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#4
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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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83 SD 84 CD |
#5
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Quote:
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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Cruise Control not working? Send me PM or email (jamesdean59@gmail.com). I might be able to help out. Check here for compatibility, diagnostics, and availability! (4/11/2020: Hi Everyone! I am still taking orders and replying to emails/PMs/etc, I appreciate your patience in these crazy times. Stay safe and healthy!) 82 300SD 145k 89 420SEL 210k 89 560SEL 118k 90 300SE 262k RIP 5/25/2010 90 560SEL 154k 91 300D 2.5 Turbo. 241k 93 190E 3.0 235k 93 300E 195k |
#6
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Quote:
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. |
#7
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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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Andrew '04 Jetta TDI Wagon '82 300TD ~ Winnie ~ Sold '77 300D ~ Sold
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#8
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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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83 SD 84 CD |
#9
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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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Seth 1984 300D 225K 1985 300D Donor body 1985 300D Turbo 165K. Totaled. Donor Engine. It runs!!! 1980 300SD 311K My New Baby. 1979 BMW 633csi 62K+++? Dead odo |
#10
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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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1998 E300D, 287k, barely broken in. |
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