In the process of troubleshooting my ignition problem I have either replaced or swapped out all things involved with the ignition. I replaced the trailing coil pack and the coil harness, and in the process I inspected my leading coil pack and it appeared okay. My question is: although appearing to be okay should I replace the leading coil pack? After replacing the trailing and the harness the only thing that seemed to improve was the idle. Which is great but did not solve my problem, as far as I know the leading coil pack could be the original and the vehicle is a 93. So if you have any input it would be greatly appreciated. thanks Jamie

 

while you're in there you may as well replace all three, don't go cheap...the leading tends to crap out faster than the trailing coils

I replaced all three and it made a big difference

 

That will depend on what you mean by 'inspected.' It's doubtful you'll be able to see a problem by just looking at the coil; the internal parts can fail without a change in the exterior appearance.


I just learned how to test the coil with a multimeter, to verify that it's within factory specs. Info is here: https://www.rx7club.com/3rd-generation-specific-1993-2002-16/testing-ignition-coils-spark-plug-wire-corroded-408014/


You might also contact superior_force, he seems to know a lot about stuff. He said he had an ignition coil fail even though it measured within factory specs.

-s-

 

haha, speak of the devil. When I wrote that reply, superior_force's post wasn't displayed on the forums yet.


superior_force, how did you determine (besides the multimeter test) that your coil was failed?

-s-

 

in my case, the car started right up and ran great until warmed up, then it would start backfiring and crapping out as soon as the coils got hot....pretty strong indicator to me the lead coil was toast....I replaced all three just because I don't relish pulling the UIM off and my car is a '93 with 65k miles

edit: all three coils passed the resistance test cold

 

btw I called Ray at Malloy and my new coils fed-exd the next day....thanks Ray (good prices, too)

 

My car runs great out of the hole but quickly falls on its face. My pattern stays solid, and i have it set at 8-7-8 right now being moderate while i troubleshoot the car. Yes, when i insepected it i only looked visually, i did not test the coil. I imagine i should just replace it anyway seeing as how it is probably the original. Thanks for any help....

 

If you do find that the leading needs to be replaced and plan on running an ignition amp later on go with a TII leading coil. A new mounting position will be needed however it works great and can handle the abuse from the amp. Try fritzflynn for the coil or the 2nd gen sale section.

 

or just run Denso Iridium racing plugs (heat range 9).....fixed my top end break up

 

I've gotta try a set of those.

 

I run ngk 8 & 9's right now....How would a faulty leading coil affect my ignition? The reason I repalced the trailing was because the car is pretty strong out of the hole, but then falls on its face. So, i figured it would be leading, is this not so? Does this coil affect ignition even in higher rpm's?

 

in a word....yes!

 

hey superior_force, how much did those coils cost you? Also, does anyone know if it would be bad or good to run 4 leading plugs instead of 2 leading and 2 trailing?

 

DVSseven, the leading coil should be MORE important than the trailing, but there is only one because both leading plugs happen to fire at the same time (as opposed to both trailing plugs, which fire at different times).

Don't forget your wires either, they are a wear item that should be replaced every couple years. A set of 4 is around $30, so you might as well do it while you've got the coils out. I just replaced mine and the car is noticeably more responsive, especially at partial throttle, and the idle has improved also.

-s-

 

Worn out stock turbo unit can act like a failing coiling, too. HKS Twin Power is plugNplay and is stock coil friendly.

 

Mark, the turbos arent old tired stockers, they are brand new 99 efini's that i had imported by Mazdacomp. I ordered the leading unit today while at work(im a service writer at the local dealership), should arrive to me at work on Friday. So, hopefully friday after my lunch break we will know for sure....thanks everyone.....

 

I paid about $140 for the leading and $120 for each trailing from Malloy

as far as plugs, I run all 9s and the insulators look good....just switched over to the Denso Iridiums

 

Has anyone here ever had a faulty leading coil, if so what were your symptoms?

 

I've had two leading coils fail:

first time I could feel the car wasn't as strong in higher rpm

second time was after motor rebuild, car would run great at idle and build primary boost real fast then fall on its face around 5k rpm.

Coils passed the FSM test both times.

Jack

 

This guy had a hard-to-solve boost problem. It turned out to be the leading coil, and there were a few vacuum hoses in the wrong places also.

https://www.rx7club.com/ne-rx-7-forum-30/car-peter-ferrells-new-shop-401172/

-s-