Just replaced all 4 coils with BRAND NEW coils and this is what happens when I hook up a timing light to the output of a coil:

All 4 new coils do this and some coils are worse than this. Is this normal?

This is on a stock 2004. Drove it around with the new coils and everything seems fine (no loss of power, no CEL).

Thanks,
FS

 

Maybe there's an issue with your timing light? How old are your spark plug wires?

 

I thought the timing light may be bad, so I tested it on an 85 RX7 (distributor style) and it was completely fine. I will test it tonight on a more modern ignition off a Toyota Tundra tonight. I have a feeling that the timing light tool is not the issue though.

The spark plug wires have never been changed, still stock, but what is the likelihood that all 4 spark plug wires are bad? If a wire was totally bad, wouldn't I have CELs all the time?

FS

 

Well, I can't test it on a '11 Tundra because there are no spark plug wires... But the timing light works perfect on the '85 RX7.

 

Is everything grounded properly? Is the light connected properly/ fully seated?

It is possible that all the coils are garbage, but I doubt that is the case here...

 

Everything is factory, ground is good as far as I know. The timing light was properly attached directly to the battery terminals.

Another thing I've just thought of... Could this be due to a faulty crankshaft position sensor? It looks like the timing jumps around when I shine the light on it...

FS

 

Your timing light is not designed to provide an accurate flash with this type of ignition setup. If your coils were truly acting as the light indicates, your engine would run horribly bad.

If your engine is running fine... Quit trying to find something wrong.

 

You have an 04 right,

It might be missing occasionally, mine did. At the higher speeds, the flicker could be a random misfire.

My sig has a First $100 thread. If mine did that, I would look at doing the electrical stuff, specifically the engine ground stuff, and try your test again. I do not think the grounding kit is really needed if you pick up star washers and a good conductive grease.

Let me know if it helps.

 

You're probably right but how come the timing light won't work on the 8? As far as I can tell--as long as there's a current being sent through the spark plug wire, the timing light can pick it up.

The flicker gets worse is what concerns me--sometimes it'll be black for 10 seconds w/o any light going off. On a side note, I did check my battery terminals and the block ground--both look great and seem solid.

What do you think?
FS

 

Engine sounds fine, you will notice right away if there is a misfire.

 

Like I said, there's just no way that's an accurate indication of your spark. Think about it... If you had no spark for 10 seconds on one or more plugs, the engine would either run incredibly terrible, or stall altogether.

 

looks more like poo steam, not smoke ... https://www.rx8club.com/series-i-do-yourself-forum-73/diy-testing-all-rx-8-coils-gm-ls2-yukon-coils-sparkplug-wires-222641/

 

@ OP

There are 6 or so grounds around the engine compartment. The one that seemed the most suspect (loose) to me was the one by the oil filter. It is a pain to get to, but is where I seem to think the coils ground to. There are also grounds on both fenders, as well as under the air box. This will sound a little dumb, but after that mod, the car seemed a lot happier, seemed to run cooler, I heard the fans a lot more and the MPG ticked up a bit and stayed there. I think you can likely get a lot of benefit without the big wires of a ground kit, but just by putting in the washers and cleaning the connectors. I do know the fender grounds were painted under the connector. That is a lousy idea. I did some resistance checks before and after and my numbers agreed with the links I referenced. I do not have the right kind of equipment to test those links with the engine running though.