Coil Pack bad, should I replace all of them?

All six of mine are original 91 coils with no problems.
I think coils are like light switches, they work or they don't.
Go to page 23-95 in your manual for the test procedure
 
Depends on the spec of your IG coil.

Since you stated that it's a 15 years old car and based on your Location info, your NSX is OBD2 spec.

If my assumption is correct, your IG coil should have 3pin.

For the 3pin style OBD2 misfire detection spec, just get all six (Front x 3, Rear x 3) using the parts no. 06300-PR7-305.

You will get six IG coils at only about US$111 inc. discount and it's not typo.
This price is for all six and not for each coil pack. I think it would be more expensive to buy just a single 3pin coil than buying all six using the above parts no.


For the 2pin style pre-OBD2 spec, I'm afraid there is no such six coil packs deal at great offer from Honda/Acura and you will need to buy it separately or you need to go for the aftermarket one if price is the highest priority.


The failure would most likely to happen at the rear bank if it was related to the rust causing the expansion of the coil head and breaking the wound wire so if you are really keen, you could replace all three at one bank.
However, compared to other popular failure like the Main Relay, IG coil failure is not that common so from this point, you may want to just replace the failed one only.


There are lots of patent involved in IG coil design and misfire detection by each car manufactures so for the IG coil circuit on NSX, you can only check the primary side of the IG coil.
Therefore, unless you have access to the IG coil test rig, you won't be able to check the secondary side with ease and thus, you can only perform partial check on it.


Kaz


 
Hi Kaz,


I have seen the rust issue on the rear bank many times. For me, what really matters is if the coil fits tightly over the spark plug. I typically test each coil for tight fitment. With age the rubber end(spark plug end)of the coil gets loose. I have found if they are loose fitting, and moisture is present, this can cause a misfire, due to the coil arcing against the head.

BTW, discount prices at this time appear to be about $100/coil.

My $.02.....

Regards,
LarryB
 
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Kaz is correct about the price from on-line vendors, and that includes 6 plugs! However, just because on-line vendors list it, doesn't mean it exists! Sort of like some of the virtual NSXs that appear for sale on Ebay!
 

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For the clarification, the parts no. 06300-PR7-305 is for the 6 x 3pin style IG coil (3 x 30520-PR7-A33 plus 3 x 30521-PR7-A33) only and it does not include anything else such as the spark plug.
In the past, I saw some vendors showing this parts no. together with the six spark plugs so I was also under the impression that it comes with the plugs but recently, one of my friend contacted Acura and confirmed the above fact.

T
his is what's inside the box. And it's for the 3pin style IG coil only.... This parts no. is not recognised in Japan or in Europe and seems like only available through US Acura/Honda.

Kaz
 
not a mechanic by no means … had a coil pack issue last year on my 93 with 40k on clock..car ran like axel foley placed a banana in my tail pipe…my mechanic in two minutes said it was coil pack..said the time to isolate which one would be the same time to replace all of them…i ordered them online brand new as well as new spark plugs per his recommendation. i thinks it was less than a hundred per coil pack and since then the car has run better than ever…it was not a lot of money to spend on the car even though i truly put about 150 miles on per year i thought it was the right thing to do… just my two cents with very little mechanical experience...
 
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