Cranks but won't start

[e9coupe]

Dirty plugs are a huge diagnostic red flag. If your spark plugs are sooty black it is time for a trip to the garbage can. They will almost certainly be contributing to the crappy operation.

BINGO! I put some cheap new copper plugs in and it's running really good now. So in the end I think the intake cam being off one tooth was the vibration it had and the cleaned (dirty) plugs was the issue after the TB was corrected. Awesome. It warmed up all the way and runs good at all temps, with an occasional pop here and there to remind me it ain't perfect. I'll drive it tomorrow.

What a saga. Thanks for hanging in there with me guys.

 

[Old Guy]

OK, for now.

You need to ask yourself how the original plugs got to looking the way they did. After seven years of use my plugs came out looking pretty much like the brand new set that I put in. I am going to make an informed guess that being one tooth off on the timing belt did not cause you plug fouling problem.

Aside for a shorter life, basic coper plugs do not have the extended heat range capability of the fine wire platinum / iridium plugs. I suggest you switch back to new OEM style plugs and then start checking the plugs every couple hundred miles to see what is happening. I am assuming the Dinan chip is just a fuel / ignition remap and did not screw up the original firmware code. If so, after a couple of hundred miles you should be able to use the service check connector to trigger the display of stored error codes assuming that the CEL has not been disconnected because did not like looking at it.

 

[e9coupe]

The new iridium plugs looked fine when I was trying to figure out the small vibration problem and I ran the motor a fair amount. The plugs turned black when the TB jumped and I ran the motor a few times afterwards while diagnosing. A new set of iridiums are going in and I'll follow your advice about checking them.

I have a small oil leak on the rear head somewhere I need to find before driving.

 

[e9coupe]

CA smog test has me concerned. I have an old cold air intake without a CARB sticker so I'll have get an air box. After that who knows how it will test. Why are the used ones more expensive that new?

 

[Mikexike]

CA smog test has me concerned. I have an old cold air intake without a CARB sticker so I'll have get an air box. After that who knows how it will test. Why are the used ones more expensive that new?

You will fail visual right away, Try to call shad at driving ambition and see if he has a used air box you can buy. You will then need to find a star smog shop that will let you hop on the dyno right away after you drive it like you stole it. Best of luck

 

[Old Guy]

I thought the NSX was 49 states compliant? I have a US market NSX. It is all stock and it has no CARB certification sticker anywhere that I can find. It does have a really big sticker on the back of the firewall with the emission control system data.

For those jurisdictions with a visual inspection I think the non stock air box will be the issue, not the absence of a sticker. If you source second hand be aware that the intake snorkel changed during the production run so you need to source a snorkel that matches up with your model year.

 

[e9coupe]

Yes, the issue is an non-OEM intake without a CARB compliant sticker. The OEM air box has a sticker on it but didn't know what it was. I've since seen one and that's not related to an emissions test. My car still has the emissions sticker on the firewall so the only issue with the visual inspection should be the air box.

 

[Honcho]

Yes, the issue is an non-OEM intake without a CARB compliant sticker. The OEM air box has a sticker on it but didn't know what it was. I've since seen one and that's not related to an emissions test. My car still has the emissions sticker on the firewall so the only issue with the visual inspection should be the air box.

Yeah you need to pass visual too. Check AH Parts- they usually have a few of them. Ebay too.

 

[e9coupe]

Found an air box. IN MY GARAGE! OMG, I think I'm losing my mind. I knew I didn't get one with the car, but I work at a wrecking yard and we had two NSXs years ago. After selling most of the parts we had a pile left over that was "free for the taking". I bought the catalytic converters for core price and took some hubs, rotors and also grabbed the air box but didn't remember I'd grabbed it. My son remembered me saying "Mine's aftermarket, I may need it some day".

It's a '97 but it fits good. Installed my new speed sensor at the same time. Swapping the newer cats on then trying the smog test.

 

[Honcho]

Free airbox is a score- those are getting pricey these days!