Hey guys so I've done some research and it sounds like I had a misfire and probably need new coils, wires, etc.. but I thought I'd run it by you all anyways.

So here's the scenario this is the second time this has happened:

I was on a rather spirited, to say the least, cruise this past weekend with two other 8 owners and m3 and an mr2, we were going around the twisties at 70-80 mph and I was keeping the car between 7000rpms and the redline as best I could, during one down shift and subsequent rev match my CEL started flashing and I don't really remember a loss of power but thats because I was very concentrated on the turn it could have been there. And as an added bonus the coolant light came on (I have had that happen before on hills prolly just the weak sensor). Now this seems to me that I had a misfire, however, I kept up the aggressive pace and the car was fine for the remaining 30 some odd miles and the roughly 120 mile ride home.

I just wanted to know if the problem is def a misfire and I need to replace the above things asap, or if there is anything I should check before I do this.

Some additional info:
car is an '05 with 49k miles
bought in may w/ 42k and not sure if the previous owner ever changed out the coils and wires.
This has only ever happened under agressive driving

Thanks in advance for any help and sorry about the essay!

-Charlie

 

blinking CEL is almost always a misfire.
even if you didn't notice a major decline in performance, the engine was most likely misfiring and the usual suspects should be checked; ignition coils, plugs, wires.

If you bought the car 7,000 miles ago and do not have the previous owner's service records you must assume that the car was never maintained properly.
if you have a multi-meter, you can test the OEM ignition coils to see if they are still performing properly. I have the instructions for testing them on my laptop so I can post that when I get home.

spark plugs are fairly easy to swap out so I'd probably do it anyways. You could check them quickly if you've got some spare time this week just to be safe.

Wires: if you're replacing coils / plugs you might as well...

if your car is running fine this doesn't qualify as an "OMG, must change immediately" scenario but since the car is used, you should probably do it anyways. (or at least, I would if I was in your shoes)

 

With 49k miles on the car and no previous records on the car. I would change out your coils, plugs and plug wires. The OEM ignition system is very weak and coils burn out too fast. I recommend upgrading your ignition system by buying the BHR Ignition Kit. http://blackhaloracing.com/products-...ition-system6/

It is very easy to install.

 

I have access to a multimeter so I would really appreciate that thank you. As for a service I have records of all the oil changes the previous owner did to it and they were very happy to give me all the information they had at hand on the car... I'm sure If I can find their contact information I can find out whether or not the coils were ever changed. But its probably something that needs to be addressed regardless of weather or not they were previously changed out.

 

here ya go: http://www.finishlineperformance.com...16-07-1793.pdf

 

thanks very much appreciate the help!

 

Although the TSB linked does a pretty good job of checking the obvious, cable voltage conveyance (inductive test) and internal coil resistance (open or short), it pretty much assumes the proper output voltage level based on these two factors. In fairness it's about the best they can do 'in the field', but may not tell the whole story of ignition robustness.

In the absense of service records for this component, and as you insightfully intend, recommend you change the 'plugs, coils and cables and be assured of a known good baseline. The ignition system is critical to proper operation, yet is often under-attended.

 

So I just changed my plugs, and decided to check my coils while I was in the engine bay.

I checked the resistance, and I'm wondering what the "normal" values would be.
All four of my coils have approximately the same reading.

Terminals A - B = 1.8 k ohms (20 k ohm setting on multimeter)
Terminals B - C = 1900 k ohms (2000 k ohm setting) or 9 M ohms (20M ohm setting, the max on my meter)
Terminals C - A = 20+ M ohms (20 M ohm setting indicates open circuit)

So, what is considered infinity on the instructions? With terminals B-C being somewhere between 2M Ohms to 9 M Ohms, I consider that pretty close to infinite (especially since it is 1000x more than A-B which has the same inspection condition). It just seems a bit odd, if they are bad, that all four would have the same readings.