how to check sparkplug coils
Thread Starter
|
New User
Joined: Nov 2008
Posts: 1
Likes: 0
how to check sparkplug coils
I have a miss in my 5.4 liter. I took it to a shop to find out which cylinder was missing. He ran a diagnostic and said I had two bad plug coils but wouldn't tell me which ones unless he did the work. How can I test the coils myself?
mccormickmd@comcast.net
mccormickmd@comcast.net
Last edited by mccormickmd; Nov 7, 2008 at 01:35 PM. Reason: wanted to add e-mail address
Elder User
Joined: Jan 2008
Posts: 605
Likes: 1
I just did this job. It may not be the Ford method, but it works. You'll need an assistant. You stand at the engine bay. The assistant starts the enine and puts it in Drive while depressing the brake. You then disconnect the electrical connector from the COPs one at a time and then reconnect them. If you notice a change in the RPM and the engine shakes a little when the connector is removed that's NOT the bad coil. If you see NO CHANGE you've found a BAD ONE. Do you have any misfire DTCs? If so what are they? I'm curious because I had no misfire DTCs, but did have two other DTCs.
Elder User
Joined: Jan 2008
Posts: 605
Likes: 1
The problem I had was no misfire codes even though I had rough idle and poor acceleration(misfires). Instead I had P0171 and P0174(Lean on bank1 and bank2). I started troubleshooting the lean condition and ignored the misfires. I have since found out other people have had misfires on the 5.4 without setting any misfire DTCs. When this happens you have to resort to some other method of finding the misfire. That's why I used the method I did. I have a good scan tool so I don't need to go to the local parts store to read my DTCs. The method I used worked with no misfire DTCs. I don't know if mccormickmd has gone to the local parts store to have them read his DTCs, but that would be a lot easier than my method. I did it the way I did because I didn't have any other choice at that point.
