Car quit running due to what I thought was a bad coil. Towed home and replaced the coil with a Bosch Blue coil. There is spark enough to feel but not enough to jump the gap on the plug. Even replaced the Magna Spark II unit with a new one, removed and cleaned all ground wires to the frame to insure a good ground. Motor turns over fine with good compression, gas is getting to the motor. Just will not fire off. Any thoughts?
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Plugs. If the coil or dizzy was the initial problem the plugs would have been fuel fouled pretty badly. Sometimes they spring back to life, sometimes they are never the same... I'd start with 4 new plugs and see what that does for you.
In addition to the above...I'd check the voltage at the coil with the key on....Bruce
Ground strap to the motor/trans.
Ground strap was removed, cleaned and replaced.
Voltage to the coil with the key on is 12.5 volts.
Tested for spark with a new plug. No viable spark but I could feel voltage the one time I held it off the back of the engine compartment.
Would a bad alternator cause something like this? It is a newer Bosch unit.
The usual suspects:
Qnty (2 ) Defective Magna Coil Modules
Defective Ignition Wires /Coil Leads
What would Fox Mulder say...
ReV
If you can "feel" the spark voltage at the plug end and it doesn't knock you on your ass, then you've got a bigger problem. Getting zapped by a decent spark should make you wonder if you just lost a couple of fingers. I'm wondering if you have a high resistance ignition switch (not uncommon, unless it's German) which could give you 12.5 volts as measured, but the current drops off dramatically as the coil starts to work. It's either that, or a corroded crimp connection in the 12v ignition wire from the switch to the coil or a bad ground to the coil case or the distributor.
How old are the plug wires?
Did it just turn damp there after drier weather?
Mitch just reminded me.......
Have you replaced the distributor cap and rotor?
Plug wires - two years.
This is Florida. It is always somewhat damp (humidity) except in winter.
The jolt from the new plug was not that strong. I was trying to see if the distributor was producing a spark.
Try looking inside the distributor cap to see if the rotor or cap contacts are corroded and yucky looking. I kind of doubt that's the problem (see earlier post) but'cha nevah know.
I would doubt that it's plug wires since they never fail as a consistent group. You either are not getting consistent current to the coil or have some massive resistance between the coil and distributor. If you want to check a suspect plug wire, check the one between the coil and distributor. A decent spark, at the plug and into your hand, should REALLY give you a jolt.
When you mentioned that you replaced your MagnaSpark, I assumed you replaced the dizzy and the cap and rotor as a whole unit, is that correct?
I'd also eliminate the ignition switch as a possible culprit. One of the things they can do when they go "bad" is to drop the 12v from the switched side of the ignition somewhere along the sweep of the key, so the motor will turn over but you've lost 12v to the coil while this happens. You can still get an occasional spark from 12v arcing through the ignition switch randomly.
That is correct. I replaced the entire MagnaSpark unit along with the coil.
Also I tested the resistance on the wire between the coil and the MagnaSpark. There was just a little resistance on the meter but I am going to get another wire and try it.
The key switch will be the next thing I will check. Is this a item that NAPA might stock?
Thanks everyone for the tips.
If it's a dash switch yes, NAPA has them. Try bypassing the switch and "hotwire" it.
Column switch will be a different story.
