Hey guys my buddy has a 1992 Mazda b2200 with 2.2l. We think his coil is bad. So what im wodnering is what the coil readings should be? If anyone could let me know this that would be great.

Thanks

Lane

 

Good question, this forum is a ranger forum, your buddy has a vintage mazda. Only '94 and newer Mazdas share anything with the Ranger. Tell your buddy that even though there are plenty of automotive forums, if you plan on working on your own vehicle, you should own a repair manual for it. The specs he needs would be in the manual. For the record, the vintage Mazdas up to 1993 were known to have computer problems due to leaking capacitors on the motherboard. What tests have been done to condemn the coil?

 

Just his basic elemination process. Not sure how he got to this conclusion, but he did and i was just wondering what it should ohm out.I didnt know year for sure ford bought mazda, but i thought it would be close. Well thanks for corectiong me, and i will keep lookin around for the right info.

Thanks

Lane

 

I think it more of a continuity question. If you don't have any current flow thru the wires then you've got a break and the coil is definately bad. It's hard to say what the ohm's should be without having the exact kind to check.

What's the symptom? Try rebuild or replace distributor?

 

Well duh if you have no continuity the coil is bad, but the reason for checking resistance is because that is a more common problem. The coils are separated from each other by an insulating resin, which over time will cause a short circuit. These shorts will lower the coils resistance, resulting in a reduced output from the coil. The electricity flowing through the wire will find it easier to jump through the failed resin and bypass loops of coil.

Again, don't know what the specs are but you want the primary resistance to be within a certain range, and the secondary to be within a certain range. You measure the primary by going from one connector pin to the other. The secondary is measured from pin 1 of the connector to the coil post.

Most parts stores have the repair manuals for the classic Mazda pickups. It contains lots of invaluable information besides the coil specs. I own a repair manual for every kind of car I've every owned.

 

To my mind it's more likely that the wire breaks rather than finds another path to complete a circuit that the electrons are searching for. I think Maxwell had some equations that you could complete to understand the boundary conditions better.

 

Yep, here they are,

Deriving Maxwell's Equations for the Potentials

You might have to go to Provo to get someone to explain them to you.

 

And that explains what? Every coil I'd ever tested that was bad still had continuity. Often the resistance was either way high or way low, but it had continuity. The dielectric resin is far more likely to break down than for one of the coils to break. You are talking about high voltage here, and that voltage has a tendency to cause electrical decay in insulators, in other words, insulators can become conductors or semiconductors when electricity tries to find a new path to ground.

Besides, why would I have to go to Provo when we have 5 other universities here?

 

I thought insulators were choosen by design engineers because they are not affected by voltage? My bad.

 

No insulator is completely impervious to the effect. You can use fewer coils which will reduce the stress and decrease the liklyhood of failure, but now your voltage output would be less and you will have to use a smaller gap, which means less spark exposure and slower ignition. Our you can decrease the density of the coils and make the coil larger to achieve the same result, but its cost and size increase, and you have to use even more coils to overcome the increased distance between them. Its all tradeoffs. OEM coils use higher quality materials and designs than the aftermarket coils, and the OEM coils consider durability highly in the design.

The coils therefore may never fail, but as time passes, the chances of an insulator breakdown increase, especially if the recommended spark gap is repeatedly exceeded or if non-OEM spark plug wires, which may have a higher resistance and a lower dielectric strength are used.

So basically the harder the coil has to work, the more likely it is to fail. If you use OEM plug wires, replace the cap and rotor on the specified intervals, again replacing them with OEM or equivalent parts, and replace the spark plugs at the recommended intervals, again with the OEM spec or equivalent plugs. On a classic Mazda, that would be either Mazda or NGK branded parts, and Denso is a good alternative.