Igniter unit

How do they fail? Why? Symptoms? I've read that in CTSC cars the blower has to be taken off. Is this a common failure on early cars?

Located where?

Hi,
We have seem many of these fail, on all year NSX's. The car just starts running on 4 or 5 cylinders and it comes and goes with different loads. We see more of them fail on track driven cars. On our race car we rubber mounted the unit to keep it away from heat and vibration. On the early Comptech SC kits you do have to remove the blower to change the unit. But not on the later model Comptech kits you do not, it is mounted right on top. Cheers, Shad

Shad, thanks for your opinion. So it's sensitive to heat and vibration. Could it explain the following scenario? The engine runs fine while cruising but under heavy load (over a high mountain) or German autobahn it starts to show signs of misfire. After a cooling phase it's ok. Means: it just acts faulty under heat but it ok when cool?

Driving Ambition:

Excellent idea with the rubber mounting to keep vibrations down, like the Borg, I will assimilate this technological distinctiveness into my own.
Thank you

Anyone have that part number {91 model}? Thanks.

goldNSX said:

Shad, thanks for your opinion. So it's sensitive to heat and vibration. Could it explain the following scenario? The engine runs fine while cruising but under heavy load (over a high mountain) or German autobahn it starts to show signs of misfire. After a cooling phase it's ok. Means: it just acts faulty under heat but it ok when cool?

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Sounds definately like a defective igniter, if you pull the engine error codes, you will most likely see the codes for misfire on 1 or more cilinders and also the code for random misfire, that is what I had when my igniter failed, with exactly same problems as you described

davidf said:

Anyone have that part number {91 model}? Thanks.

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Just bought one

30120-PR7-A01

rsevo6 said:

Sounds definately like a defective igniter, if you pull the engine error codes, you will most likely see the codes for misfire on 1 or more cilinders and also the code for random misfire, that is what I had when my igniter failed, with exactly same problems as you described

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Rene, thanks for your valuable input. I've OBD I which doesn't show errors related to misfire. But I'll change it and see what happens.

Thanks again!

goldNSX said:

Rene, thanks for your valuable input. I've OBD I which doesn't show errors related to misfire. But I'll change it and see what happens.

Thanks again!

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You're welcome:wink:
Weird that the igniter which is a fully in resin enclosed electronic unit seems to fail quite often.
Also weird that the igniter is the only ignition part that cannot be measured through, there is no check method for it other than replacing it with a known good unit.
By the way, the igniter is the same part number on ALL years NSX

As for measuring, some things are hard to measure if they only occur under certain circumsstances. For example, it took me more than two years to locate a bad fuel pump and this can't be just me. If I would have brought the car to the dealer he would have changed part by part until he would have 'fixed' the problem by chance leaving a big hole in my pocket. What would a world be without the internet and without nsxprime? :wink:

My dealer stated 30120-PR7-A01 for 91-94 so I thought they've benn changed for 95+ but I trust you .

goldNSX said:

As for measuring, some things are hard to measure if they only occur under certain circumsstances. For example, it took me more than two years to locate a bad fuel pump and this can't be just me. If I would have brought the car to the dealer he would have changed part by part until he would have 'fixed' the problem by chance leaving a big hole in my pocket. What would a world be without the internet and without nsxprime? :wink:

My dealer stated 30120-PR7-A01 for 91-94 so I thought they've benn changed for 95+ but I trust you .

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It took me a long time to identify the igniter as the problem as the misfires with the engine running on 4-5 cil were momentarily at first.
After stopping some time when this happend, the problem disappeared at first, engine running OK, but the problem became worse every time and in the end the engine was permanently running on 4-5 cil.
As I have all the manuals, I checked all ignition parts for the values given in the manual and all of them measured good. The only part that had NO checking method was the igniter, so in the end I changed it with a 2nd hand from a '91 and voilá the problem was gone.
Mind you, measuring doesn't always show a defect as about 1 year after having the igniter problem, the car again had misfire code on cilinder 3.
I again checked everything and all was according to measuring values, so I again expected the 2nd hand replacement igniter to have failed.
As the error code this time was only giving misfire on cil 3, I moved the coil to another cilinder and the problem moved with it, so I knew for sure the coil was the problem, I replaced it with a new one and problem solved.
Strange thing was however that the defective coil looked absolutely new, no rust at all and it was within measuring specifications according to the manual, it however was defective, really weird!

The SM measurement procedures often only help you if the part is completely defective. You recognize a misbehaviour long before. Your story shows that too. I'm getting an ignitor unit, the front coils would be next if the problem is not solved. The rear ones have been replaced and sealed against water some years ago. Young lady getting older...

I am at a loss why these electronic parts (even the fully in resin enclosed igniter) fail.

Is it age, mileage, operating temps or just chance?

My former EU '98 was used as a daily driver for 2,5 years by it's former owner regardless rain or snow before I got it.
When I sold it to MvM about 6 months ago it had run close to 100K Km and with MvM now raking up the mileage fast during his new ownership :wink::biggrin: it still has never had any electronic gremlins.

My present from the US imported CTSC '98 is mint, has been pampered all it's life, only used in dry weather and always garaged. Has only run 24,5 K Mls from new untill now (of which 5K Mls with the CTSC) and already had the igniter and a coil fail, go figure.. :frown:

It's a combination of all this. Heat and vibration are the main causes. Water sometimes for the coils. Oh, BTW I've been pm'd how I've sealed the spark coils on the rear engine. See pic (white strips on the cover). It's a primitive solution and I improved the look of them in the meanwhile.
BTT: Rene, your silver one was stock, your red one was already equipped with CTSC and maybe header. That's where all the additional heat and vibration is coming from. And the car formerly lived in the US which may was hotter climate than cold Switerland (yes, we miss that car :tongue: There are two similiar cars on the market right now :wink.

Thank you for the pic.
My .02 is that all electronics have an expiration date eventually. Relays are the worst IMO. Thats why I've replaced many over the last few years as "maintanance". I don't want to wait till I'm stranded. Yes they may have lasted for years but they were 16/17 years old and I think thats a good lifespan for electronic parts that see vibration/heat/cold on a daily basis. Not everyone may agree with me but if it's done a little at a time the cost does'nt overwhelm you.:wink:

Does this sound like an igniter issue? Car starts fine when cold. I can drive it for say an hour straight without shutting engine off and it runs fine. If I have to shut off the engine for a few minutes and restart it. The car will start, but then the engine starts to shudder and RPM starts to drop as if it were going to stall. If I give it some gas the RPM will go up and engine will stabilize. Never have this issue when the car is started cold, only occurs on warm restarts and happens intermittenly. Thanks.

topgunsnsx said:

Does this sound like an igniter issue? Car starts fine when cold. I can drive it for say an hour straight without shutting engine off and it runs fine. If I have to shut off the engine for a few minutes and restart it. The car will start, but then the engine starts to shudder and RPM starts to drop as if it were going to stall. If I give it some gas the RPM will go up and engine will stabilize. Never have this issue when the car is started cold, only occurs on warm restarts and happens intermittenly. Thanks.

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Not sure. Could refer to a vacuum leak or 'false' air or several more things. What did you test so far?
I only thought about the ignitor after going through several steps like main relay, ignition coils, fuel pump. Older ladies use/need more make-up.