THSCC Forums

Anybody have the current part number for the NB Miata Coil pack? The MazdaSpeed diagrams show BP4W-18-10XA, but it appears this is an old number. I know I can oder it under the original, but I'd like to know correct pricing before hand.

Also, anybody (Eric?) know of a debug proceedure to tell if the coil is the problem - the 2min diagnosis appears to be I have no spark at cylinder #1. Given their history, the coil pack is first thing on my list after plug/wires, especially given the cold-start issue the car occasionally had.

Why is it that the one time I need info from Miata.net the site is down? If it's not one thing....

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Dustin Fredrickson
-- I'm a nobody --

The Jan'02 parts catalog shows what looks like BP6D-18- 100A .


Gary F. says the Miata net forums may not be up till the weekend as he's on vacation. The Miata emails list are still working you could post there.
Have you measured the coil resistance?


Frank

My NA manual says the resistance of the coil should be around 10K ohms. Not sure about NBs. Coil problems can also be intermittent (i.e. heat related) which might not show up in your driveway with a VOM.

On second thought, have you swapped coils?

I *think* the NBs use the same two coil arrangement as the NAs. The coils are just "on the plugs" in the NBs. So one coil fires two plugs. The coils are identical so just move them and see if the problem follows the coil.

Frank

So he has to be at home for the server to be up? Why!?

_________________
Vincent Keene
'06 Ford Mustang GT (track rat)
'15 Dodge Charger R/T (yeah, it's got a HEMI!)
'07 Ford Fusion SE (205,000 miles and counting)
'98 Chevy Z-24 (retired)
'93 Acura Integra (Team SWB 24HOL Car)

The forums are back up. All is well again in Maita-land

Frank

the NB coil packs are at the back of the engine just like the NAs. Don't you have a CEL on? If you could get it read, that would tell you where to look. You may have a different problem that has resulted in the ECU going into failsafe mode.
IIRC Coil pack failure is not unheard of, but not a common occurance. Have you washed the engine lately? Miatas are real susceptable to getting water into the plug wells where it's hard to dry and will cause missfiring. Also have you changed plugs lately? Not using antiseize and/or not tightening them properly is another common problem.
Are the coilpacks interchangable (Don't know, I never had to change one on ours) if they are, swap them and see if the problem follows one coilpack. If you are stuck doing a backyard diagnosis, put a spare sparkplug in the end of a plug wire and hold the metal part against the valvecover. Have someone crank over the engine and see if the plug fires. Do the same for each wire. If all fire, you need to look elsewhere than the coilpack. When you solve the problem, pull the underhood room fuse and leave out for more than 60 sec. Replace and you'll have cleared the OBD II codes. You'll probably have to reset the radio buttons.

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Thanks for the tips guys - right on the money. Turns out it is one of the coils. Time to break in the MazdaMotorsports account...

_________________
Dustin Fredrickson
-- I'm a nobody --