Author Topic: Glow Plug circirt blowing fuse (Read 4312 times)

thunder chicken · « **on:** February 24, 2007, 01:40:52 pm »

Hello all. Long time reader, first time poster! I have usually found the answer to my questions using search, but this one has me stumped.

Hisory on my car 94 VW golf turbo diesel. 400,000km+. The altenator recently went, and was rebuilt by a good shop. Shortly after, the temps went down to -40, and the car was hard to start, even being plugged in. I am using 10w30 oil. I checked the glow plugs, since they have been in for about 3 years ( at least 100K) and they all were burnt out.
SO i replaced them ( luckly the temp went up to -10c) After a few hours of cursing, I had new glow plugs installed. Before I put the new ones in, I tested the wires that hook up to the glow plug/bus bar with a multi meter. When i would turn the key on, i had voltage, 10v or so if i remember correctly. After about 15sec, it would drop off, just like it was supposed to....... Now with the new plugs in, everything hooked up, i hear a pop under the dash when i go to start it. It was a giant 50A fuse near the top of the relay panel. SO i put in another, and POP.

Help!!!! the only thing i can think of is the wires on the bus bar are not hooked up right....there was a washer on the glow plug stud when i took it apart, but i dropped it and dident bother to find another..... the wires are put on the glow plug stud after the bus bar was.......

thanks for any help!

QuickTD · « **Reply #1 on:** February 24, 2007, 06:01:46 pm »

Make sure you have both of the thick red/white wires from the circular connector hooked up to the #4 glow plug/bus bar. If one of those wires is resting against the engine block or head it will blow the fuse instantly.

saurkraut · « **Reply #2 on:** February 24, 2007, 10:21:19 pm »

If everything else is ok, you might have an internally shorted glow plug. Try pulling the wire off the first plug, make sure it doesn't ground out, and see if you blow the fuze.

If it blows again, the wire to the plugs from the fuze holder might have worn through by rubbing on something.

burn_your_money · « **Reply #3 on:** February 24, 2007, 10:23:26 pm »

Quote from: "saurkraut"

If everything else is ok, you might have an internally shorted glow plug. Try pulling the wire off the first plug, make sure it doesn't ground out, and see if you blow the fuze.

If it blows again, the wire to the plugs from the fuze holder might have worn through by rubbing on something.

To expand on that, if the fuse doesn't blow hook up the second GP, and then the third and then the fourth.

Give the plugs some time to cool down between cycles though, you don't want to burn them out.

BlackTieTD · « **Reply #4 on:** February 25, 2007, 09:42:21 am »

i'd look for the a hot wire grounding out somewhere as suggested. then i'd give power to the fuse directly from the battery. if the fuse still blows then you know its on the plug end of things. if it doesnt blow when you power directly from the battery then you know its on the relay side. i'm no good at troubleshooting electrical but this seems like it would be on the plug end of things. since it still does it with brand new plugs i'd really dig for a grounded hot wire.

thunder chicken · « **Reply #5 on:** February 25, 2007, 10:52:10 am »

Thanks for all the replies!!

The trouble was in the Bus Bar. It has seen better days, and is bent up quite bad. It was touching a fuel line, grounding out. Funny how something so simple can cause so much trouble!!

burn_your_money · « **Reply #6 on:** February 25, 2007, 05:17:55 pm »

glad to hear you got it sorted out