COPS Misfire Again?
#1
COPS Misfire Again?
2002 Expy:
How can one tell if a COP is bad? Is there a way to test them. I replaced #4 in December and it fixed my misfire, then problem reappeared shortly afterward. Removed, cleaned and regreased the insulator and problem went away only to reappear yesterday. The problem seems to occur after it rains and with cold weather. I pulled #2, #3, and #1 just to look for evidence of water. Also, how much dielectric grease needs to be used on the the wire and silicone insulator?
How can one tell if a COP is bad? Is there a way to test them. I replaced #4 in December and it fixed my misfire, then problem reappeared shortly afterward. Removed, cleaned and regreased the insulator and problem went away only to reappear yesterday. The problem seems to occur after it rains and with cold weather. I pulled #2, #3, and #1 just to look for evidence of water. Also, how much dielectric grease needs to be used on the the wire and silicone insulator?
#3
#5
#6
But for a marginal or intermitiant coil issue, you really need to watch while under load, the current flow through the coil primary. For this you need an amp clamp and a digital storage oscilloscope to capture the current wave form.
For example, suppose there is a clean break in the coil's internal winding. The resistance test would show no continuity through the primary side of the coil and you could declare the coil as bad. Now suppose there was a weak spot in the coil's primary winding. It may be able to handle the micro amps of current the ohm meter sends through the coil's winding and the coil would appear to be good. But if you put the normal amount of current, maybe five to ten amps through the winding, the weak spot would break down and you would see the fluctuation in the currents wave form.
So to put it another way - the resistance test can show a coil is bad, but it can't prove that it is good. <!-- / message --><!-- sig -->
__________________
Thread
Thread Starter
Forum
Replies
Last Post
ultimatekimberly
Modular V8 (4.6L, 5.4L)
9
09-02-2004 06:29 PM