Ignition coils - again?

[goldnsx]

My car is not running on all cylinders at idle with a cold engine. All ignition coils have been replaced in the past:
. front: 2011, now have 30k miles on them
- rear: 2006, now have 60-70k miles on them, the rear cover has been modified, no water is going in there.
- igniter unit: 2011
My guess is that one of the rear ones is acting up again.

My question: NGK states that their coils are consumables by stating they hold between 40 and 50k miles. Should I replace all three or just the one I find acting up? How long do they hold in the NSX from experience?

[Pride]

What a bummer.:(
Why not replace with OEM coils, I know they might cost more but I don't believe they have a service life quoted and my coils have lasted 140k+ miles now with no misfires.

[Kaz-kzukNA1]

Probably best if I wait before writng many suggestions until I get further info.
I know your NSX is 91 with CTSC but don't know any modifications around Fuel Reg, Fuel pump, INJ, ECU, intake/TH body/CAT/header/backbox, etc.

What rpm and eng temperature are we talking about because eng won’t be at 800rpm when cold.
Is it during the fast idle warming up stage or is it around 900 – 1,000rpm but eng still not fully warmed up?
What happens once the eng has fully warmed up or at higher rpm range like over 6,000rpm? No more issue?

Did you replace the IG coils with the OEM or the aftermarket ones in the past?

Is it misfire or hesitation? If misfiring at 800 rpm, you are very likely to hear the 'pop' at the exh tail pipe.



At this stage, I’m not sure it's the IG coil issue or/and mixture related, etc.


For your information, the IG coil on our NSX is from TEC (Toyodenso Co. Ltd.) and under normal usage/maintenance, should last for long-long years/miles. It's a transformer.

If rear bank coil cover gasket and the IG coils were treated properly, there are lots of NSX out there with the original coils from the factory at all six cyl with lots and lots of mileage.
It's not the latest design but at least, it's direct IG system.
Mine is 23 years old with about 154K miles.


Kaz

[goldnsx]

My NSX is a 91 with CTSC v3.
- Toyota Supra TT fuel pump
- FPR: the CTSC comes with its own unit. The fuel pressure is steady and fine.
- Injectors are the stock 240 ccm which have been cleaned.
- the ECU is stock as the CTSC requires it to be. The CTSC works well with the Europe version of the ECU even though the CTSC is designed around the US ECU.
- Intake including throttle body (cleaned too) is completly stock except for the CTSC
- Water temp sensor replaced
- Air intake sensor fine
- header 97+
- exhaust stock
- the car passed SMOG last year
- ignition coils OEM, not aftermarket
- I drove quite a lot recently, so fuel (usually BP because I believe in their advertising :)) is fine as well.

It starts idling at around 1300 rpm (depending on temps) and goes down to around 800 rpm with the engine getting warm. I started it up this afternoon and didn't notice extraordinary misfire or the like. Above 2000 rpm it runs fine, no loss of power, no misfire. I shows the symtoms of my old rear ignition coils I've changed back 2006 or so. At idle, it was not running smooth but with higher revs the 'weak' ignition coil wakes up and starts to fire. One thing that I noticed: the left exhaust flow is steady (keeping your hand in the flow) while the exhaust flow on the right is not so steady at idle.

[Kaz-kzukNA1]

Hi, goldnsx.

If running OEM IG coil, very unlikely to fail again unless it’s soaked in moisture.
Did the issue happen all of a sudden or gradually got worse and worse that became noticeable?

What kind of spark plug are you using although if it’s OK at higher rpm, very unlikely to be the cause.

The fast idle at 1,300rpm is bit low compared to the normal spec of 1,500rpm although yours is still within the spec.
Don’t know the effect of FI friction though.
How is your base idle rpm?
Again, I don’t know what kind of effect it will have with FI friction but can you idle at 600 – 650rpm with EACV disconnected?
I have driven several FI and/or heavily modified NSX in UK and Japan. Some had idle rpm control issue but others just idled fine.


Kaz

[goldnsx]

The new rear coils didn't get any moisture since installation (self-made seal). I'm tempted to pull the individual coils plug for testing if I have it pronounced once again.

The spark plugs are one step colder and come with the CTSC kit, changed recently.

Idle is 800 rpm, higher when cold, 1300 rpm was a guess, depends on the outside temp. One thing that I recall is that the idle is problematic (very low) for maybe 10 seconds or so if you start up a hot engine but after that it's fine.

It was very obvious after the long winter period where I was not able to start the car every month. It was not running on all 6 cylinders after the very first start, after that it was ok I guess. I didn't felt small vibrations anymore.

One thing that itches me is still: One thing that I noticed: the left exhaust flow is steady (keeping your hand in the flow) while the exhaust flow on the right is not so steady at idle.

[ozon02]

Hi Goldi,
How this adventure ended?

Regards
Mario

P.S.
I wanted to make calls but I saw on TV that your national team is playing the match!!!

[goldnsx]

Yep, no good time for call. :)

This problem turned out to be a bad injector seat seal, the rubber o-ring where the injector sits on in the cylinder head. One was torn due to false installation. It's not a good idea to have it ON the injector while you force the fuel rail in position. The rubber o-ring should be IN the cylinder head BEFORE you push the fuel rail with the injectors into position. I've recognised it by chance while doing another injector cleaning and was quite surprised.

All problems went away. My garage where I went for an emissions testing today mentioned that it's running quite rough compared to a BMW. Well, I said, that's just the way it is, 90 degrees V6 in raw mode, no balancing shafts.

[ozon02]

Hi,Goldi
What is your injector cleaning interval?
I sent mine to a specialist facility for diagnostics - 2 of them are Ok , the remaining 4 show abnormalities under different "driving" conditions.
I have 4 options for solving the problem:
1.Purchase of new OEMs
2.Purchase refubished OEM from Christian ATR
3.Purchase Aftermarket (Id-injector etc.)
4. PURCHASE CHINA "oem" INJECTOR
Add.1
Maybe NA2 injectors will be better (the same price as NA1)

[goldnsx]

My car got neglected in the last two years due to some private 'issues'. So I can't answer your question easily.

Injectors like to be exercises regularly. Long storage is 'bad' for them. 'Bad' means that they get a little bit restrictive, maybe 10%. They need some time to recover after some months of storage.

Cleaning them normally solves the problem. Not sure if your shop who tested them wants to sell you something. Maybe try another shop. They should clean them an retest.

[ozon02]

...as always, a competent ,objective answer

Best regards
Mario