plug leads question!?

[Raven]

Ok I took my leads off from the distributer cap to the spark plug and checked them for resistance and i would have though they would read 0.

i.e. they connect fine, but I am getting reading of 4.7 and 3.6 witch seams odd to me.

Anyone know if they should read 0 or not? Perhaps time to get a new set?

..Raven...

[chipa]

Nothing has a resistance of 0 ohms. Any cable will have a certain amount of resistance.

Just not sure what would be a normal amount for spark plug leads.

[Raven]

Sure but i am talking at a reading of 100 ohms not 100,000. I'm just trying to find the cable that seam to be slightly less connected as I am getting a pulse.

Most things like power cables and audio have a 0 ohms reading.

Any way.. if anyone knows the "normal" reading let me know!

..Raven..

[jrp928]

Some cars have resistive leads, like 3k ohm...find the specs and check, useless without. As long as it doesnt change with flexing or heating, it might be ok. Try looking at night, running, lights out...if you seen any sparks jumping, insulation has failed. I just bought a set off ebay (champion LS156?) from UK for ~$35 inc postage....keep an eye out.
jp 89, 91 sp

[andrewgrazier]

u need a new set when ya car starts runniinngg craptastic!

[Cosmo Dude]

If the leads ran zero resistance then your car would be nothing but noise. 2k ohm to 10k ohm sounds about right. Remember it's 35,000 volts that drives the spark so anything under 100,000 ohms should work fine.

[Raven]

hmmm ok. well I am hearing the pulse in the FM radio so there is a breakdown of at least one lead. and sometimes it does miss a fire but its very intermitant.

My guess is that the rubber is breaking down over time and thus causing more resistance than is normal. So anyone else got any ideas?

Ok know how on earth i get a new set at low cost? As mazda want $105 for a set.
Dam those long custom plug ends... hehe

..Raven..

[Cosmo Dude]

If one of your leads is past its use by date then it's related plug will be different in appearance from the rest, post a pic.
Genuine Mazda leads last on average 10 years. Aftermarket Hi-po knockoffs are lucky to last two and cost heaps more. How much does Repco, Autobarn, etc... want for a set of leads?

[Raven]

They are all the same age, but they have never been replaced I have had the car since new so that would make them only 8 years nearly 9 old. They all look the same in aperiance.

.Raven.

[BigMal]

I bought Top Gun 8.8mm leads got 7 years out of them and they look good too.
Cost was $100 through Autobarn

[Raven]

Finally I found what I am after.

The minimum resistance is of little concern, but as a rule of thumb they should be higher than 7 K ohms per metre for suppression leads. Too low a resistance can cause radio frequency interference (RFI). The resistance in the lead is designed to suppress RFI.

http://www.topgunleads.com.au/tgtable.gif

a good chart showing what I want...

The leads look nice... guess its new clutch from Rup.. then leads..

..Raven..

[Rupewrecht]

Good to see you've got your priorities in order

[chipa]

Originally Posted by Raven

....
Most things like power cables and audio have a 0 ohms reading.
...

You might want to check how voltage drop occurs then

[jrp928]

mY HAYNES MANUAL LISTs LEADS AS 16K ohms. Mine measured 6k on longest down to ~4k on shortest. new Champion leads started at 12k and went down. Seems to run about the same on either set, but the red 8mm Champs look better....
jp 89 bg