Took Becky (now for sale) out last night with a potential buyer. Went for a good hard drive of about 10 miles with no problems. Noticed about 5 mins from home that the led mileage display on the Revotech speedo had gone blank and the needle was stuck at 30mph and running slightly rough. The guy didnt notice and was very happy with her and deciding after he gets back from his holiday away. Went to start her in the garage again and the battery was flat so charged her overnight. Came to start her this morning and as the engine turned over a few times then the main 30amp fuse blew. Replaced and turned the ignition to notice that the live feed to the engine on the back of the ignition barrel got very hot and then smoke appeared from behind the dash at which stage I switched off and here I am..

Once the battery was charged the speedo needle and display all reset ok. So any ideas from the symptoms described and where do I start (in laymans terms please)

Check the regulator/rectifier and any earth leads you can find.

wich ignition switch u have? std sierra or aftermarket?

live feed to engine, u mean the one that goes to the alternator? Check if it hasnt undone itself at the alternator side and check wether the insulation of the wire isnt damaged anywhere along the way.

And to me it smells like your 30 amp fuse is too strong, fuses are meant to protect your cabling, not the equipment. So fusing is according to cable size.

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Originally posted by Peteff
Check the regulator/rectifier and any earth leads you can find.

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quote:

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Originally posted by Werner Van Loock
wich ignition switch u have? std sierra or aftermarket?

live feed to engine, u mean the one that goes to the alternator? Check if it hasnt undone itself at the alternator side and check wether the insulation of the wire isnt damaged anywhere along the way.

And to me it smells like your 30 amp fuse is too strong, fuses are meant to protect your cabling, not the equipment. So fusing is according to cable size.

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Go check your earths!

well, the switch might be the problem, if it is not up to the job, then the contacts may be worn causing sparks and stuff.

First try to find the cause of smoke, my bet is on the ingition switch itself, indicating that it can't handle 30 amps If it is a wire that has gone hot, then the fuse is too heavy for the wiring and it wasn't right in the first place. A 20 or 25 amp fuse will probably blow instantly, but u could try it, if it goes, then you have to find out what is using so much power, and all u can do is measure or "trial and error" method (ie diconnecting stuff and trying) but that could use up a lot of fuses.

Do you have a schematic of the wiring? That could help a lot, as you know what the 30 amp fuse is feeding.

[Edited on 17/5/10 by Werner Van Loock]

From the symptoms I'd say the switched live out of the ign barrel to the fusebox/circuits has gone to ground, which would take out the main fuse.

I'd be looking for where this wire has rubbed through and touched earth if it was mine

HTH
Cheers
Stott

OK thanks up to now.. just to be clear it is the MAIN 30amp fuse by the battery that feeds the whole car electrics.

Also Iv'e been driving her daily for 6 months so its not the initial setup but something that happened on the drive last night.

[Edited on 17/5/10 by FFTS]

As I said above, the only way that fuse should blow is if you've got a short to earth after the fuse on the way to the ign barrel or from the barrel to the fusebox or to the starter solenoid as this is unfused (by the fusebox)

But given your first post description (warm lead from ign barrel to engine) the short won't be on the battery to barrel side.

It shouldn't be fault with any of your circuits as long as they are all fused individually and correctly

Cheers
Stott