Glow plug problems
Glow plug problems
Thanks.
Gasoline Fumes
08-28-2009, 01:52 AM #1My neighbor's 1984 300D seems to have 5 dead glow plugs. Is it possible that the controller/relay burned them out, or did they just fail one-by-one until it won't start anymore? When exactly does the controller turn the plugs on and off?
Thanks.
(08-28-2009, 01:52 AM)Gasoline Fumes My neighbor's 1984 300D seems to have 5 dead glow plugs. Is it possible that the controller/relay burned them out, or did they just fail one-by-one until it won't start anymore? When exactly does the controller turn the plugs on and off?
Thanks.
It's *possible* depending on where you live, but you are probably experiencing something else. The controller/relay energizes the plugs when you turn the key to the "on" position and keeps them glowing for about 30 seconds(IIRC). There is also a temperature sensor for the glow plugs as well. I am unsure of exactly where it is in that circuit, i.e. does it only engage for certain temps, etc...if so that may be another issue.
I'm sure someone else who knows more about it will chime in sometime soon.
W123 Mods: 4 speed ** manual climate control ** '85 Kalitucky intake ** manual windows & full tint ** Euro headlights retrofit w/bixenon projectors ** 4 brake light mod ** Vogtland 50mm drop front & Lesjofors S600 drop rear springs ** 16" rims ** late w126 brake spindles, rotors & calipers ** full suspension rehab ** Bilstein HDs ** AL129X alternator & 1/0 starter and charging cables ** 300GD clutch/flywheel ** AFCO 80103N radiator & Earl's 41610 oil cooler ** custom block-off plate, remote oil filter & t-stat ** MW IP w/ tomnik's 6.5mm 'Holly' elements **
S124 Mods: 400E Rear subframe ** SL600 Brakes ** Late 300E 210mm diff ** SLK230 6 speed ** 17" CLK rims ** Vented RF Fender ** Facelift Hood, Headlights, and Lower Cladding **
OBK# 62
SurfRodder
08-28-2009, 01:48 PM #2(08-28-2009, 01:52 AM)Gasoline Fumes My neighbor's 1984 300D seems to have 5 dead glow plugs. Is it possible that the controller/relay burned them out, or did they just fail one-by-one until it won't start anymore? When exactly does the controller turn the plugs on and off?
Thanks.
It's *possible* depending on where you live, but you are probably experiencing something else. The controller/relay energizes the plugs when you turn the key to the "on" position and keeps them glowing for about 30 seconds(IIRC). There is also a temperature sensor for the glow plugs as well. I am unsure of exactly where it is in that circuit, i.e. does it only engage for certain temps, etc...if so that may be another issue.
I'm sure someone else who knows more about it will chime in sometime soon.
W123 Mods: 4 speed ** manual climate control ** '85 Kalitucky intake ** manual windows & full tint ** Euro headlights retrofit w/bixenon projectors ** 4 brake light mod ** Vogtland 50mm drop front & Lesjofors S600 drop rear springs ** 16" rims ** late w126 brake spindles, rotors & calipers ** full suspension rehab ** Bilstein HDs ** AL129X alternator & 1/0 starter and charging cables ** 300GD clutch/flywheel ** AFCO 80103N radiator & Earl's 41610 oil cooler ** custom block-off plate, remote oil filter & t-stat ** MW IP w/ tomnik's 6.5mm 'Holly' elements **
S124 Mods: 400E Rear subframe ** SL600 Brakes ** Late 300E 210mm diff ** SLK230 6 speed ** 17" CLK rims ** Vented RF Fender ** Facelift Hood, Headlights, and Lower Cladding **
OBK# 62
1987 300SDL 6spd manual om606.962 swap project
1985 300td euro 5spd wagon running
willbhere4u
08-28-2009, 10:53 PM #3Before you start the engine it runs when the light on the dash is on till it turns off! then you can start the car that's it! in colder weather they stay on longer dose you glow plug light come on and turn off ???
1987 300SDL 6spd manual om606.962 swap project
1985 300td euro 5spd wagon running
ForcedInduction
08-29-2009, 12:40 AM
#4
Check the strip fuse in the relay and voltage to the plugs before assuming all 5 plugs are dead.
It was about 65°F during the testing.
Gasoline Fumes
08-29-2009, 12:58 AM #5The light doesn't always come on. I stuck two good used plugs in it and it started, but the light didn't come on at all. The plugs should turn off when the light turns off? When I was testing it, I was still getting over 12v at the plugs after the light shut off. The light was only on for 5 seconds or less. And if I unplugged the small plug on the relay, it would click. And click again when I plugged it back in. I tried another relay from an '84 300TD and it did the same thing. And my '85 300D does this too. It seems like the plugs are on whenever the ignition is on. I should recheck it now that it will start. I might just recommend a conversion to manual glow plugs. I did this to my '83 GMC and I love it. Are the Bosch plugs self-limiting or will they burn out if powered too long?
It was about 65°F during the testing.
The glowplugs don't actually turn off until the starter is used or the relay's safety timer cuts out.
The relays you tested are working normally.
ForcedInduction
08-29-2009, 01:12 AM
#6
The dash light has no relation at all to glowplug operation. Its only a suggestion to the driver. Unplugging the small plug and plugging back in is the same to the relay as cycling the ignition switch, the relay sees ignition power turned on and activates the glowplugs.
The glowplugs don't actually turn off until the starter is used or the relay's safety timer cuts out.
The relays you tested are working normally.
One more question! Are these any good?
Glow plugs on eBay
My neighbor picked these over the Bosch.
Gasoline Fumes
08-30-2009, 04:27 AM #7Thanks! Now it all makes sense.
One more question! Are these any good?
Glow plugs on eBay
My neighbor picked these over the Bosch.
(08-30-2009, 04:27 AM)Gasoline Fumes One more question! Are these any good?
"The glow plugs are not made by Bosch, but the company has manufactured for Bosch."= I'm embarrassed to mention the manufacturer name because it will kill the auction's value.
Glowplugs should be a once-every-5-years-or-so purchase. Spending an extra $3 each is very insignificant in the long run to get the best quality.
Even when I'm pulling junkyard glowplugs, I only keep the Bosch and occasionally the Beru (if they look new-ish). The used crankcase oil is worth more than Autolite glowplugs.
ForcedInduction
08-30-2009, 04:34 AM
#8
(08-30-2009, 04:27 AM)Gasoline Fumes One more question! Are these any good?
"The glow plugs are not made by Bosch, but the company has manufactured for Bosch."= I'm embarrassed to mention the manufacturer name because it will kill the auction's value.
Glowplugs should be a once-every-5-years-or-so purchase. Spending an extra $3 each is very insignificant in the long run to get the best quality.
Even when I'm pulling junkyard glowplugs, I only keep the Bosch and occasionally the Beru (if they look new-ish). The used crankcase oil is worth more than Autolite glowplugs.
1987 300SDL 6spd manual om606.962 swap project
1985 300td euro 5spd wagon running
willbhere4u
08-30-2009, 12:12 PM #9Autolight the official glow plugs of NASCAR seriously that's what they say on the box! my friend put them in and they lasted 2 months! complete crap!!!
1987 300SDL 6spd manual om606.962 swap project
1985 300td euro 5spd wagon running
I have been able to blow them out right away by hooking one up to the 220V stick welder.
ForcedInduction
08-30-2009, 10:11 PM
#10
Also, leaving the glowplugs on will not burn them out. Yes it will shorten their overall lifespan but it won't kill them in one session. I've tried to blow out a few used junkyard Bosch glowplugs by hooking it up to a truck battery with a 12v charger on high for several hours. None had a change in heat color or died during the tests. Your battery will be drained to nothing before the glowplugs give out.
I have been able to blow them out right away by hooking one up to the 220V stick welder.
(08-30-2009, 10:11 PM)ForcedInduction I have been able to blow them out right away by hooking one up to the 220V stick welder.
awesome...
W123 Mods: 4 speed ** manual climate control ** '85 Kalitucky intake ** manual windows & full tint ** Euro headlights retrofit w/bixenon projectors ** 4 brake light mod ** Vogtland 50mm drop front & Lesjofors S600 drop rear springs ** 16" rims ** late w126 brake spindles, rotors & calipers ** full suspension rehab ** Bilstein HDs ** AL129X alternator & 1/0 starter and charging cables ** 300GD clutch/flywheel ** AFCO 80103N radiator & Earl's 41610 oil cooler ** custom block-off plate, remote oil filter & t-stat ** MW IP w/ tomnik's 6.5mm 'Holly' elements **
S124 Mods: 400E Rear subframe ** SL600 Brakes ** Late 300E 210mm diff ** SLK230 6 speed ** 17" CLK rims ** Vented RF Fender ** Facelift Hood, Headlights, and Lower Cladding **
OBK# 62
SurfRodder
08-31-2009, 02:06 PM #11(08-30-2009, 10:11 PM)ForcedInduction I have been able to blow them out right away by hooking one up to the 220V stick welder.
awesome...
W123 Mods: 4 speed ** manual climate control ** '85 Kalitucky intake ** manual windows & full tint ** Euro headlights retrofit w/bixenon projectors ** 4 brake light mod ** Vogtland 50mm drop front & Lesjofors S600 drop rear springs ** 16" rims ** late w126 brake spindles, rotors & calipers ** full suspension rehab ** Bilstein HDs ** AL129X alternator & 1/0 starter and charging cables ** 300GD clutch/flywheel ** AFCO 80103N radiator & Earl's 41610 oil cooler ** custom block-off plate, remote oil filter & t-stat ** MW IP w/ tomnik's 6.5mm 'Holly' elements **
S124 Mods: 400E Rear subframe ** SL600 Brakes ** Late 300E 210mm diff ** SLK230 6 speed ** 17" CLK rims ** Vented RF Fender ** Facelift Hood, Headlights, and Lower Cladding **
OBK# 62
Gasoline Fumes
09-05-2009, 04:13 AM #12The mystery plugs are VSP (Vespark Industrial). Made in Taiwan. They work great for now. And if they die, I get paid to change them again!
ForcedInduction
09-08-2009, 02:39 PM
#14
Extract them. A broken glowplug is a royal PITA, especially #1 and 5, but its not the end of the world. Anything on that side of the engine can be removed for access.
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