Porsche Repair: porsche not firing, 924 porsche, abrupt manner

Question

-------------------------

Followup To

Question -
I drove my 924 porsche and set it down when i started it back up it started to run rough then the coil stop firing i put another coil on it from an older car but still nothing happens the coil doesnot fire could you tell me what this could be and could i hook the coil up to the battery directly and then plug it up to the distributor cap would the car start

Answer -
Hi Latron,

Don't wire the coil to the battery, it gets sufficient voltage right where it is.

But, if you suspect the wiring to the coil, have you tested it for voltage with the ignition on?

If you suspect the coil, I'd suggest testing the primary and secondary resistance...check both coils you have.

There could be other reasons for a no-spark condition, but let's focus on the coil until you are satisfied.

Dave

i kind of know that both of the coils are good and its getting power to both wires but i dont know why its not firing when i turn the key could it be the ignition key doing this and not giving power to the negative and positive wires of the coil when i turn the key

Answer
Hi Again...

Sure, it could be the ignition switch but the abrupt manner in which the car started acting funny suggests a wire came loose rather than it just wore out.

I'm going to assume you don't have a voltage tester, so try this first.  You know how if you took a length of wire and touched both terminals of the battery ( very quickly, then pull them away) you'd get a tiny spark at the wire end, right?

So, take one end of the wire and attach it to the positive (hot side of the coil, turn the ignition on and quickly touch the other end of the wire to a ground...not the coil ground, somewhere else on the chassis.  If there's 12v coming to the coil, you'll see another spark at the wire end.

Check it out.

Dave