Author Topic: Randomly blows ignition fuses - scalding wires  (Read 5714 times)

Offline smurfinator

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Randomly blows ignition fuses - scalding wires
« on: August 09, 2014, 10:13:22 pm »
I have driven the car for several years working fine but, on top of all the other issues, it has begun to fry ignition fuses and nearly melted a (+) supply wire to one bank.

I am running 1.0.73 on a V3.2 board.  Using coil-on-plug with wasted spark.

Under normal operation, the igntion bank supply wire is cool.  But sometimes when cranking over or simply turning on the ignition without cranking, the fuses will blow and I will check the supply wires and they will be hot.

I have checked an rechecked all of the ground.

For the love of all that's holy, WHAT THE HELL could be causing this behavior?  I just don't understand.

Audi ABZ 4.2 V8 in 1993 90 quattro
TTV 60-2 flywheel and cam sync
firmware: 1.2.20

Smurf blue (BMW Laguna Seca), hence the name!

Offline gunni

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Re: Randomly blows ignition fuses - scalding wires
« Reply #1 on: August 11, 2014, 04:51:29 pm »
Most likely your battery compensation dwell timing.
The lower the voltage the more compensation it gives and overcharges the wires/coil

Offline mattias

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Re: Randomly blows ignition fuses - scalding wires
« Reply #2 on: August 11, 2014, 05:27:55 pm »
I also recall with old firmware like this that you could get spark at ignition on.  I would definately recommend upgrading to more recent firmware, it will also require a bootloader upgrade to access fw  1.2.20 and beyond.