Bench Test Coils

[lance.rowland]

06 explorer 4.6l 3v engine. Bench test coil over plugs. Primary resistance calls for 5.5 ohms. Secondary calls for 5500 ohms. Manual voltmeter on lowest ohm setting. Touch two primary leads i get 2.1 ohms on all 8. Does this mean all are bad? Should i be able to touch spring and one of primary leads to get secondary reading?

 

[MotorCityFats13]

it should be like testing the old coils and wires.... they call out for a baseline number anything higher it is bad.... so if it specs at 5.5 and you get 2.1 then you have a super-duper coil, the higher the resistance means more lost power unless you get 0 then you have a broken connection.... wires are calculated per foot so 5500 sounds about right for a 4 inch wire boot.... the longest wire on a conventional ignition system when it is bad is around 16k ohms

 

[lance.rowland]

Thanks. I'm having the infamous bucking/studder at 40-50mph. Already had plugs changed. All 8 plugs are ohm'ing close to same at primary but secondary are 5690 to 5740.

 

[steve6534]

Thanks. I'm having the infamous bucking/studder at 40-50mph. Already had plugs changed. All 8 plugs are ohm'ing close to same at primary but secondary are 5690 to 5740.

Search for another thread on here regarding transmission fluid / torque converter shudder. I had the same problem and suspected ignition at first as well. It only happened at that speed and the torque converter lock was slipping until I changed the fluid.

 

[D Hook]

I had the same issue also. Had a transmission shop drop the pan, change the filter, refill and the problem went away. Didn't do a total flush. Probably have the same thing done in a few months, just to get rid of more of the old fluid.

 

[lance.rowland]

How long ago did you two have your fluids changed? Any reoccurring issues so far?

 

[steve6534]

How long ago did you two have your fluids changed? Any reoccurring issues so far?

About 6 months for me. Has been perfect ever since. Before the fluid I replaced the plugs (again) even though they only had 40k on them and tested all of the coils.

If you've never changed the fluid (or aren't sure of the history) I highly suggest not getting a flush that most places offer. There's plenty of horror stories of that circulating contaminants back into the trans and it having new problems not long after. Either drop the pan and replace the fluid / filter yourself or find a place that will.

 

[lance.rowland]

Here is some new info. I initially had a cylinder 8 misfire. Had the plug changed. It was fouled out pretty bad. No more light but still same issues. Had all plugs changed. Still bucking and studdering. I put different coils in and it helped a little but still doing it.
I#was mistaken on my on readings. The primary should be .5; mine are .7-.8. The secondary should be 5.50.....I'm getting 5.69- 6.10 when checking all of them. Does this sound like they are going bad?
My next step was going to be fluid change. It only has 64k miles on it.

 

[steve6534]

Here is some new info. I initially had a cylinder 8 misfire. Had the plug changed. It was fouled out pretty bad. No more light but still same issues. Had all plugs changed. Still bucking and studdering. I put different coils in and it helped a little but still doing it.
I#was mistaken on my on readings. The primary should be .5; mine are .7-.8. The secondary should be 5.50.....I'm getting 5.69- 6.10 when checking all of them. Does this sound like they are going bad?
My next step was going to be fluid change. It only has 64k miles on it.

If there's no misfire code set (or better yet no misfires while monitoring $06 data) I wouldn't worry too much about the coils.

The mileage is really low for the year but some of them could have been hard miles on the trans. Since it's time anyways I would just go ahead and do it.

 

[D Hook]

How long ago did you two have your fluids changed? Any reoccurring issues so far?

Had mine done in early June. Nothing since.