Coil Noise Suppressor/Capacitor wiring

[A2Z]

I am trying to determine how the noise suppressor/capacitor, mounted adjacent to the coil (see image) is wired up. My 1978 260Z coupe's noise suppressor has in-line wires (see image), coloured blue and black. The blue one with the spade connector is connected to one of the coil terminals (negative I think), but the black one with the bullet-type connector was disconnected and tucked in under the coil. There doesn't seem to be an obvious location as to where the black lead would terminate, so perhaps there is something missing on my car.

I had a look at the internet pictures of the recently auctioned low-mileage260Z and grabbed the attached screenshot, but that only seems to illustrate where the blue wire goes, which is the same as on my car (they are about the same age vehicle).

I have seen some cars with a single wire suppressor, and some with no suppressor, but there appear to be three OEM noise suppressor numbers, so presumably there are variants. I think the suppressor on my car is original and I am trying to keep the car stock.

If anyone is able to assist, please, perhaps with a photograph that would be greatly appreciated?

Thanks.

 

[Turn & Burn]

Suppressors with two leads were more commonly fitted to cars with fm radios, single leads were for am/mw radios. The leads connect between Coil +ve and earth, hence the reason it was tucked behind possibly?
Not sure they were original figment though?

 

[A2Z]

Thanks for advising. There is some really useful information in your answer. I just checked some images of my car, and the blue lead does actually connect to the positive terminal on the coil. I don't believe any UK 260Z's came with an FM radio as standard and mine just has the AM stock unit!

I presume the single lead suppressor would earth through its metal casing. I am reasonably confident that two-lead suppressors were fitted to some S30 cars, as I have photographic evidence of that, although one of the OEM replacements in my parts book has a single lead with a bullet connector. On the two lead unit I have, the bullet connector would be on the negative, black, wire. I cannot see what the single lead suppressor would connect to, as the coil has spade connectors. If the two lead suppressor was not earthed would it still work?

Also, on the single lead replacement I have is the text "-0111 -00 150 -0.5 S W". My two lead unit seems to have the text "NCC 47D 250". Does anyone know through those numbers if the single wire unit would work with a stock Hanshin 260Z coil, as there doesn't seem to be any correlation between the numbers.

Thanks.

 

[Jimbo]

mine had the same suppressor but i removed it as most new radios since the late 90s have built in suppression and no longer affected by this kind of interference.

 

[A2Z]

Thanks Jimbo,
I am not sure if the existing radio suppressor has ever worked, because the last time I started my car was around 2006. There was always a high pitched whirring from the radio which got louder as the engine speed increased, although I assumed that was from the alternator. I can't say I used the radio much anyway, as the engine noise produced a better soundtrack. I'm always learning some good information from this site which will all help when I finally get round to getting the car on the road.
Thanks again.

 

[Jimbo]

sorry A2Z i havent forgotten about this ive just been mega busy i will try and find the supressor for you monday

 

[A2Z]

Thanks Jimbo,

Very much appreciated. If someone does know how these two-wire suppressors are wired up though, or even provide an image of one correctly installed, that would really help. At present I can only see that the blue wire goes to the positive terminal of the coil, so the black wire is simply left hanging for now.

Thanks again.

 

[A2Z]

260Z Noise Suppressor

I have attached a couple more images of the suppressor for information.

Thanks.

 

[Jimbo]

so after much faffing about I've found the suppressor thing and here are the piccys.

 

[Jimbo]

one wire is black the other is green, i can't really make out the nonsense written on the side but it definitely came off my 260 bolted to the side of the coil

 

[Jimbo]

here are the connections on mine. it does have a bullet connector like yours on the black cable which I'm pretty sure bolted down with the coil bracket so hopefully will narrow down how to refit it back on

 

[A2Z]

Hi Jimbo,

You have a PM, but just to say that is exactly what I am looking for, thank you. It is in much better condition than the one on my car, where the case has corroded. That "C" shaped connector in your image makes more sense than the spade connector that is fitted to one end of the unit on my car (the loose end that seems to have nowhere to affix).

From what I can find, my car was built in October 1977 (but registered September 1978). Is the car that your suppressor came off an earlier or later build than mine?

Thanks again.

 

[toopy]

looking at other suppressors available online, most, if not all appear to be metal bodied and therefore earth via the bracket
Where as your one appears plastic bodied, held with a metal bracket! maybe thats why it has the earth lead

 

[A2Z]

Thanks toopy,

I think you are correct in your assumption that most suppressors will earth through the metal casing itself, hence the single lead to the positive side of the coil.

Interestingly enough, the two-wire suppressor on my car has got a metal case, but it is so corroded it may appear to be plastic! At each end of the two-wire suppressor is a flexible soft plastic boot that protects the otherwise vulnerable soldering to the suppressor itself, although the unit does otherwise appear to be sealed against moisture ingress.

I am grateful that Jimbo managed to find an OEM suppressor that he no longer needs, so that problem has now been resolved. However, if someone does know how the second (black/negative) lead is connected, I would love to find out! As I noted in an earlier post, the suppressor that Jimbo found had a different connector on the negative wire, which makes a little more sense to me than the one on my car which had a spade type connector. Any images of a genuine one fitted to a car would really help.

Thanks everyone for all the information to date. I do think it will be worth my while getting a multimeter and start to learn a little more about how the electrical system on these cars works.

 

[A2Z]

260Z Noise Suppressor

Just to add to the post above, I had a look at the metal casing on the two-wire suppressor I have and it seems to have an "E" embossed into the bracket, which perhaps stands for earth? However, that would appear to make the black cable redundant, which doesn't make a lot of sense to me unless the bracket itself was affixed to an insulating material.

 

[andrew muir]

Just to add to the post above, I had a look at the metal casing on the two-wire suppressor I have and it seems to have an "E" embossed into the bracket, which perhaps stands for earth? However, that would appear to make the black cable redundant, which doesn't make a lot of sense to me unless the bracket itself was affixed to an insulating material.

I had a metal bodied suppressor fitted to my original coil. It had a spade connected to the possitive and was mounted to the body next to the coil the bullet connector was not connected anywhere, build date of my car was late 77

 

[A2Z]

260Z Noise Suppressor

Hi Andrew,

Thanks for taking the time to post up that information. It appears that your late 1977, like mine, was wired the same way with a "floating" negative wire to the suppressor. Attached is a picture of how it fits together under the bonnet on my car (although the "floating" negative lead cannot be seen as it tucks away behind the coil).

Regards.