Hi,
Please forgive the noob if anything doesnt please you in this
The coil resistances you posted don't seem right.
The should have a resistance of 1.xx Mega Ohms in one directions and infinite resistance on the other direction.
The primary of the coil is (like) a (PNP aka power)transistor, forward bias has finite resistance and reverse bias should have infinite resistance.
The fact that you are getting +1 -2 and -1 +2 to be the same indicates that your coils are fried or you are testing the wrong terminals.
I think you are testing the wrong terminals. I cant find my Haynes manual right now, but this is how you test the rear coils:
If you stand in front of the car and look at the coils, the order of pins is 1,2,3.
Test 2 and 3. Pin #1 has no significance.
+2 -3 should be 1.xx Mega Ohms. -2 =3 should be infinite resistance (aka O.L. or whatever your multimeter reads) {I am almost certain I got the directions right, but if not, just swap the readings for +2 -3 and -2 +3).
Also, if the primary is bad, you should be able to find a P1320 code. The ECU can only detect if the primary is open because no current will flow then. However I believe the more pertinent problem when it comes to the coils is the secondary starts breaking down. The primary has 12 V and the secondary has several kV, and there may be a dielectric breakdown leading to a short by means of an internal spark. Your ECU cannot find this, and if it is intermittent, spark testers will not be able to get it.
My car has been running rough for a while, and last week it got worse - whenever I started accelerating the CEL would blink (cyl # 5 misfire), and the light would go away if I babied my car for a day. I checked all coils, their primaries checked out perfectly. I changed coil # 5, and the misfire under load went away. (It still idles rough though. Replaced 3 and still ran rough. Swapped old 3 (Mitsibushi) with 1 (Hanshin) and it still idles rough - but a little less rough).
Most times, with failing coils, the misfire will be intermittent, and the ECU will NOT be able to detect and throw a code. So, either replace all 6 or wait till the ECU throws a code and replace that particular coil.
I now have 2 coils, which may or may not be bad. (I am not really sure if I have a coil problem or something more, I have been trying to figure out, made a few posts and am awaiting a response. All mechanics I went to ripped me off and found nothing at the end of the day
).
If you are willing to experiment I can ship you those coils for just the shipping cost.
-Sharat
Linear Mode
