Spark Plug Lead,s question

[HandyAndy]

I,m just putting the finishing touches to my car & thought about this.......

Do the Plug leads need to have the word "Surpressed" ( or words to that effect) written on them to pass the IVA ?

cheers
andy

[shh120m]

Is this something to do with anti radio interference? If so I think all modern ht leads are suppressed nowadays. I could be wrong though

[flyerncle]

There is mention in the IVA manual Andy but cant remember what/where it says but is definately to do with suppressing interference with other equipment.

Most O.E. leads have some marking on.

[HandyAndy]

Cheers Nathan, Paul...

I checked my current plug leads today, even tho they are of the "Motorcraft" brand, they don,t have any markings on them to show they are of the surpressed type,
So should I look for some that have the markings or just accept that all modern leads are manufactured to this requirement? & would Mr IVA man be happy if they don,t show any markings?

thanks
Andy

[davidimurray]

Andy - I'm in exactly the same boat - think I got the same leads as you!

The manual says -

1. The HT ignition system must be fitted with radio interference suppression equipment.
2. The trade name or mark and trade description must be present on the interference suppression equipment
3. There must be a maximum of 120mm separation between trade markings on suppression cables.

I've assumed that they will need leads with markings on them so I plan to get some new ones before IVA. Seems better than taking the risk I have read about a couple of cars failing on this

[HandyAndy]

Cheers David,
I think item 2 in your post confirms that the leads must be marked showing they comply with the interference suppression requirement .....I,ll go and get a new set, like you say, wouldn,t want such a small thing to cause a problem at the test :(

Tho, I,ve seen some leads on ebay costing around £60 :eek: ....I,ll be looking for some cheaper ones :D

cheers
andy

[ozzy1]

Take your old leads with you to the local motor factors and you can usually buy individual leads cheap as.

[flyerncle]

Used to be able to buy seperate suppressers that screwed to the middle of the cable,they had to be fitted for some competition work and were a pain and kept stopping the spark so we drilled and glued them on.;)

[baz-r]

could you lay your hands on a set just for the test andy? ;)
your using a cvh right i will see what my old lump has fitted
bit odd this because im pritty sure almost every modern ht lead id suppressed
thease days

[Bonzo]

Just my thoughts for what they are worth Andy :)

Number 2 on David's list says to me .... The word Motorcraft on the leads should be good enough for the IVA inspector.

I belive Motorcraft is an original OEM part & as such, the leads would be surpressed in accordance with the guidelines.

OEM leads have been supressed for years & the makers name should be good enough proof of, type approval.

That said .... If you are in any doubt, change them, not worth paying out for an IVA re-test over a set of leads ;)

[HandyAndy]

Thanks guys, :)

Baz, yes I,m using the 1.8CVH, good idea about "borrowing" a set of leads...but I think Ronnie may have sussed this as the IVA manual states a "Manufacturer" / Trade name must be stated on the leads.....and as you say most ( I imagine ALL) leads are made to comply with the suppression requirement etc....

Tho I will keep my eyes peeled for a set of leads that actually state " suppressed" on them .

Thanks for your input guys, I suppose the IVA manual is open for lots of "Interpretation" :eek: :confused: ...just would be an annoying reason for a £90 retest etc etc for the sake of the plug leads .

cheers
andy

[davidimurray]

I have a slightly different take on this - just because a part is a replacement it does not mean it is spec for spec an equivalent. No 2 in my list says Trade name AND trade description. Hence I think that unless the leads are actually marked how can the IVA inspector confrim that they are suppressed (a bit like the issues around fuel filler hose). The safest option is to get something that has markings on it - a quick look around the net and the NGK site shows there are a couple of standards ISO 3808 and 6856 for spark plug leads and suppression.

I think the best option is to get a set of leads with an ISO code and the word suppressed on them if possible.

[JakeH]

hi

we've just done a bit about this at college so i'll pass the word on

EVERY car should have radio suppression on the leads as it can interfere with radio and even TV signals.

it can also interfere with the modern 'fly by wire' systems on some new cars, a couple of the merc's that it was first fitted on decided they were going to jam the throttle wide open and end up in a ditch.

dont know for IVA but a receipt or packaging may keep them happy?

Cheers

[HandyAndy]

This is/has been an interesting discussion, lots of good idea,s & points of view :cool:

May I ask the forum members that have passed the IVA test what leads they had fitted please? ( what markings the leads had etc)........did the examiner check the leads etc etc

cheers
andy

[alga]

From what I've learned about the IVA test on this forum, it's down to the tester. So it would be best to find out who the tester will be when booking a test and then ask him what's his opinion on this issue.

[Enoch]

here is my take on it: Originally Ht leads were copper, they played merry hell with radio and tv as the high energy transients were effectively a spark transmitter. These leads have not been used for donkey's years, nearly all leads now are made of a conductive carbon core that has inherent suppression characteristics. In other words modern leads don't need suppressors because the resistive carbon is itself a suppressor. When I last did SVA the inspector had some sort of device that measured the RFI (radio frequency interference) My car passed ok. I think the rules are there for copper wires and possibly old points based ignition systems which emit all sorts of nasty radio interference if the condensor has gone. If your wires are all sort of floppy (very technical, I know ) then they are resistive carbon and should be fine, it they are quite rigid they are most likely copper and they will fail. My leads were not marked but other testers may be a bit more pedantic than mine was.
end of sermon.
Enoch

[mark]

My take on it is similar to what enoch has said, non suppressed leads haven't been used for a long time and all modern style leads should be fine

As always though its down to the tester on the day :rolleyes:

At my iva he did have a brief look at the leads and quickly moved onto looking elsewhere, mine had a couple of ISO numbers on them nothing else and it went through with flying colours