Coil pack resistance - FSM misprint?

[Renbuguy]

I'm trying to sort a misfire on #1...and now #3. Came to mind that it may be the coil packs due to the misfires all being on that side. Searched here and found pages of the FSM with coil pack testing procedure. Either there's a misprint in the FSM or mine are all toast?

My test results @ 10deg C (50deg F)
Primary
#1 - 1.1 ohms
#3 - 1.2 ohms
#5 - 1.2 ohms
Secondary
#1 - 12.2k ohms
#3 - 12.2k ohms
#5 - 12.2k ohms

- are my primary results too far above? Should I do another test at 'Hot' temp ranges to be sure?



Here's a post by GSGALLANT, who looks as though they haven't posted since 2016, that explains what I'm getting at.

"There are two locations in the manual that list the ranges. The first says:

Primary: 0.67 Kilo-ohms to 1.05 Kilo-ohms
Secondary: 9.3 Kilo-ohms to 16 Kilo-ohms

And the second says:

Primary: 0.67 ohms to 1.05 ohms
Secondary: 9.3 ohms to 16 ohms

Based on my test results, I think (hope) that the correct ranges are actually:

Primary: 0.67 ohms to 1.05 ohms
Secondary: 9.3 Kilo-ohms to 16 Kilo-ohms

Can somebody confirm this?"

 

[phattyduck]

I'm trying to sort a misfire on #1...and now #3. Came to mind that it may be the coil packs due to the misfires all being on that side. Searched here and found pages of the FSM with coil pack testing procedure. Either there's a misprint in the FSM or mine are all toast?

My test results @ 10deg C (50deg F)
Primary
#1 - 1.1 ohms
#3 - 1.2 ohms
#5 - 1.2 ohms
Secondary
#1 - 12.2k ohms
#3 - 12.2k ohms
#5 - 12.2k ohms

- are my primary results too far above? Should I do another test at 'Hot' temp ranges to be sure?



Here's a post by GSGALLANT, who looks as though they haven't posted since 2016, that explains what I'm getting at.

"There are two locations in the manual that list the ranges. The first says:

Primary: 0.67 Kilo-ohms to 1.05 Kilo-ohms
Secondary: 9.3 Kilo-ohms to 16 Kilo-ohms

And the second says:

Primary: 0.67 ohms to 1.05 ohms
Secondary: 9.3 ohms to 16 ohms

Based on my test results, I think (hope) that the correct ranges are actually:

Primary: 0.67 ohms to 1.05 ohms
Secondary: 9.3 Kilo-ohms to 16 Kilo-ohms

Can somebody confirm this?"

Yes, your interpretation is correct. And your measurements look like the coils have the correct resistance. The leads of the meter and the connections will add 0.2-0.5 ohms in most cases. You need a special meter to measure resistances below maybe 5 ohms accurately.

That doesn't mean the coils are NOT the issue... but the resistances are correct. Swap coils around and see if the problem moves (yes, I believe you did that a while ago - worth a re-check).

-Charlie

 

[T4R2014]

Maybe off topic, but I replaced some original coils(even had new rubber boots) that tested within spec with some new Densos. Very noticeable difference. Just from shear age I recommend replacing these now and keeping the old ones as spares. I've honestly ever seen a "bad" OEM coil, just cracked boots on them causing issues. They are very tough units.

 

[Renbuguy]

Maybe off topic, but I replaced some original coils(even had new rubber boots) that tested within spec with some new Densos. Very noticeable difference. Just from shear age I recommend replacing these now and keeping the old ones as spares. I've honestly ever seen a "bad" OEM coil, just cracked boots on them causing issues. They are very tough units.

Good info. Unfortunately swapping coils between cylinders hasn't moved my misfire. All the boots look good. I'm sure, like you said, new ones would be even better, but my goal is to diagnose and fix the misfire.

 

[2TH4IST]

Maybe give the injectors a look at if moving coils didn't move the miss fires. You can also do a compression and leak down test too.