[buzzalfa]

My S4 died so far as getting spark out of the coil. I have some very knowledgeable friends who know Alfa's very well, however this problems is alluding us. Cranks sensor and just about every connection has been looked at and tested, still no spark from the coil.
I did notice this morning the Bosch relay with the red stripe was warm this morning along with the CPU. I don't think this is normal. I unplugged the relay and the computer cooled off. Pin 30 coming into the relay connector is hot with 12v with out the key even on.

Any thoughts?

Thanks

Tommy

 

[andylarry]

Is the coil positive post showing 12v+ when the ignition key is on? Is the coil negative post getting pulsed with 12v+ when the engine is cranking?

 

[buzzalfa]

The coil is showing 12v with the key on. When starting the volts drop to 10.8

 

[andylarry]

The coil is showing 12v with the key on. When starting the volts drop to 10.8

 

[andylarry]

There are three ports to the coil. Two primary, and the center one which is the secondary. The primary positive post gets 12v+ from the ignition switch. The primary negative gets a pulsed 12v+ from the ECU. When both work you get a high(er) voltage burst through the center post which then goes to the distributor cap to be distributed (by the rotating shaft of the distributor, and the rotor) to each spark plug wire, to each cylinder. When cranking, 10.8 volts to the coil primary + post is good. To check for the pulse on the coil primary negative post, I use a simple test light. Looks like a screwdriver with a wire coming out of the bottom and a light bulb in the handle. Be sure to have a fully charged battery (12.5 volts or better at rest) Attach the wire end to a good ground and hold the pointy end to the coil primary positive post. Turn key to on. Bulb should light. Make sure that the coil wire is connected to the distributor cap, or to a properly installed spark checker tool. Hold the pointy end to the coil primary negative post. Crank the engine. If the bulb in the handle flashes quickly, the coil is receiving a signal from the ECU. If not, there is a problem with the crank sensor, ECU, or chassis wiring.