What is the end result? When I relocated my coil, I forgot to bolt it down properly. I just noticed arcing from the coil body to the nearest body (chassis) point. Could this be why the engine isn't running well???

 

Iwould like to know also. I had know arcing and it
ran fine, but I just grounded it, just in case

 

You did the right thing by grounding it.

I was setting Code 45 (Rich Exhaust) intermittently. Once in closed loop, my O2 sensor's voltage was oscillating extremely slowly. So slow that my WB displayed a very lean mixture when the O2 voltage was low, then causing a rich mixture when it was high. This caused the idle to hunt, etc.....

I think I figured out this coil thing. Once I grounded the coil body, all my symptoms appear to have disappeared. But I only ran the engine until closed loop was attained. It's just too hot in my garage, about 120. I'll run the engine more when it's below 100 degrees outside -- after 10pm tonight. In any case, Tim Burgess (moderator) says the coil was producing EMI (electro-magnetic interference), or "noise" while poorly grounded. This can cause many weird electrical anomolies. I read in my shop manual under Code 45 that the ECM looks at this "noise" as reference pulses. This causes the ECM to widen the injector pulse width, causing the system to go rich. It seems to make sense....

Willie

 

Interesting, thanks

 

Willie I'm glad you posted this. I am experiencing EMI on my large cap HEI equipped Z28 and need to get it resolved soon!

I have guessed it has to come from the alternator or coil, I have tested different plug wires and plugs to no avail.

Would it be safe to assume if any coil is improperly grounded it can cause significant EMI? I don't see how mine cannot be grounded due to the coil in the cap but I have to start somewhere.

Any input anyone?