diesel blowing out 80 amp glow plug fuse on 300 sdl

Hey guys. I changed out my glow plugs today and after getting wires and battery hooked up again, I turned the key, heard "pop" and the 80 amp was blown. The glow plug light will not light up, i checked the
bulb. I jumped #1 and #3 to test circuit, and still no light. Any ideas? Oh and the car wont start now. I did before and ran crappy till it got warm. Temp is in the 50's today and not real different than usual for this time of year.
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80 amp fusible links do get tired and break. And when it does there is NO current to any glow plug. Try a new fusible link - available from dealer for $1 or $2. (Also buy a spare.)
If the link blows again, either, a (new) glow plug is shorted internally or a glow plug wire is grounded to the engine.
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i checked the wires to see that they didnt touch the engine, i think one of the glow plugs was spinning internally when i attached the lead with the 10 mm nut. new back arnly glow plugs, ill test it in the am. glad it was number 6, at least its easy to get to.
how do i tell if the system is with or without afterglow?, i think its non afterglow because it has the fuse instead of relay. i would have to follow a differnt procedure to diagnos the problem with glow plug light failure, correct? thanks
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TG if the fuse is blown, does the engine run? That is the scary part for me. old car, always starts, until now :( new glow plugs now no workie.
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If the fuse is blown there's no power to the glow plugs. It *will* start without glowplugs but you may have to crank it for a very long time. 2 mins on, rest for 5, repeat. On about the 7th time it will start. Probbaly. Don't ask how I know this.
If the glow plug was spinning that deosn't sound right. Replace it and the fuse and I'm sure it'll be fine.
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The motor needs GP's to start - in very hot weather it may start without them but still harder than if the GPs were working.
So, the answer is: the GPs have to work!
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I guess even though the GP light didnt work, they still worked a little bit? At least enough to start the car. It just didnt sound like there was any chance of it starting with the fuse blown. When the fuse and old plugs were in, the kinda chug chug chug roughly and finally started. With the blown fuse, it just sounded like I was turning an engine with no fuel or anything, which was my fisrt thought. Maybe there was something electronic that prevented it from starting. I checked the vac. to the pump and it looked ok. Ill fix bad GP and replace fuse and see how it goes. thanks guys.
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Battery --> fuse --> glow plugs
That's it. Nothing else i that circuit. (ok, the ignition switch, but...)
I can't remember off hand what the liht means when it's off. One plug bad, or two or something like that. But it'll certainly energize some glow plugs when the light does not come on.
But, with no fuse, it's dead Jim.
I've started my car with only two working glo plugs in -44 weather, it just starts a WHO LOT faster when they all work, and they work better when new.
I replaced mine at xmas and so far I haven't had to use a block heater this xmas.
Conventional wisdom says the cheap Monarch plugs don't last as long as the BOSCH ones, but they burn hotter.
If the fuse blows, replace it. Carry a spare. Change the glow plugs every fall and you'll NEVER have a glow plug problem.
I took pics when I did mine and there is a handy trick that saves youhalf an hour. I'll write it up and post it this week.
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Definitely post the glow plug info. I didn't remove anything and had a tricky time getting number 2 in, the one behind the injector pump. The rest just require some patience. I think that now that I figured out how many joints and extensions to use on my 3/8 socket, it will go faster on my other SDL. Same problem with old plugs and no GP light. It's nice having 2 SDL's. I can swap stuff out to test the bad part before buying new.
Thanks for all the groups help. My MB mechanic just got out of the business here in FL. Too bad, he was one of the only guys that charged what it really took to fix the cars, usually half the time of book, 'except leaking rear freeze plug :(' Always busy, always behind. So I either have to fix the stuff myself or go to the sharks here in Fort Lauderdale.
Thanks again.
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Sounds like that Swede I knew down there... in Largo I think... Go to his house... pay him twice as much to fix your car... make him happy...
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I guess even though the GP light didnt work, they still worked a little bit? At least enough to start the car. It just didnt sound like there was any chance of it starting with the fuse blown. When the fuse and old plugs were in, the kinda chug chug chug roughly and finally started. With the blown fuse, it just sounded like I was turning an engine with no fuel or anything, which was my fisrt thought. Maybe there was something electronic that prevented it from starting. I checked the vac. to the pump and it looked ok. Ill fix bad GP and replace fuse and see how it goes. thanks guys.
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the fuse fixed the starting problem. after checking the glow plugs for engine grounded wires, testing voltage of #30 on preglow relay to ground then #1 and #4 on 4-5 plug for voltage, I checked the bulb in cluster put it all together and it fired right up. its 40 degrees and it fired up so fast it scared me. glow plug light even works now. now lets see if my wife waits for it to go off. :P
not bad for over 350,000 miles on the 6 banger.
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For a fast check, disconnect the wire from the suspect glow plug, wrap it with some tape and secure it. Then see if she starts and doesn't blow the fuse and you'll know if that plug is the short.
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