Ignition Coil issue

The clue here is your observation of:

" The out come is always the same the Check engine light comes on and my reader always says it is misfire on one of the cylinders. What happens is that the cylinder that the Coil pack sits on misfires but the opposite cylinder will fire with the same coil pack."

One side of the HV side of the coil is shorted to or is breaking down to ground. I would assume you have an intermittant, open in the ignition wire going to the alternate spark plug or a gap in that spark plug that is too wide. As a result the coil secondary is being over voltage stressed and is breaking down.

Replace your defective coil, ignition wires and spark plugs with OEM replacements.

snipped-for-privacy@gmail.com wrote:

CarKB.comhttp://www.carkb.com/Uwe/Forums.aspx/toyota/200708/1- Hide quoted text ->

I have done that twice now. I have changed all plugs and wires each time. What else if anything could cause the same ignition coil to malfuntion? Is the ignitor and the ignition coil all one part? If it is a seperate part is there a way to test it for the correct voltage?

Is it possible, since the fault follows the coil, that something is damaging the coil? What pops to my mind? Temperature - is the coil too exposed to heat? Another option is some fluid that may be dripping on the coil (engine oil, ATF, windshield fluid, coolant?) and cause it to fail? The obvious, such as grounding is taken care of? Solid connections? Nothing that rub/s the wires? Go with a fine tooth comb and try to eliminate each item. Good luck and do report to us what you found.

I would guess that something is zapping it out, that is, there is an errant ground somewhere that is damaging the coil.

I don't know this engine at all, so I wouldn't know where to look, but this is what I would look for...

I wonder if you take it to the dealer and they fix it, if they will get to diagnose it for real in 2 or 3 months.

Jeff

Did you use OEM spark plugs and wires or aftermarket?

I have used both OEM and aftermarket.

Assuming you have had the vehicle for a few years, has anything happened to it that might have caused the original coil-pack to fail? Folks in this news group seem to get excited about using only OEM parts. Personally, I haven't had any problems with after-market, new parts. But I'd stay away from after-market rebuilt parts. Are the coil-packs you bought new or rebuilt?

Jack

That is the thing I was trying to figure out. What would cause the coil pack to fail since they don't fail all the often? I tested the current coil pack ( which is from cylinder 3) this past weekend and everything was within the limits on both primary and secondary coils. I pulled the plug from the cylinder three, which is what reported the and to my surprise it was shot. The white ceramic around the electrode was cracked. Other than that the plug looked new. No excessive wear or deposits.

I looked into it a bit more and came up with some different ideas on why or how this could happen. I went here to compare what my plug looked like with others

It was in-between breakage and over heating. Leaning more toward over heating since it was just cracked.

So the over heating is caused by the following:

1. Possible causes are overadvanced ignition timing
2. Air/fuel mixture too lean
3. Water or oil level too low
4. Plugs not fitted (tightened) correctly
5. Plug heat range too hot.

How would I check for overadvanced ignition timing?

How would I check the Air/Fuel mixture?

Hook up an OBD II scan tool, hook up a timing light, short connectors TE1 and E1 in the diagnostic connector under the hood, start the car, point the timing light at the timing marks next to the lower pulley, and see if ignition timiing is somewhere inthe neighborhood of 8 to 12 degrees BTDC.

The OBD II diagnostic should be able to detect a lean air/fuel mixture. If you get diagnostic trouble code (DTC) P0171 or P0173, then the system is too lean.