Ignition leads

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Hotrod
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Ignition leads

Post by Hotrod »

A great day at JDM Coombe today, however, after a track session my boy limped in with the car miss firing, said it had no power :sad:
As I've only just done the cam cover gasket I checked the plug holes for oil.
Thankfully none but number one plug lead had a crack all the way down one side and two was melted out of shape. I knew one was in need of replacement due to oil contamination but I was shocked to see two had melted.
Could this be due to number one breaking down or do I have another problem?
On the up side we still managed to get home :D



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Re: Ignition leads

Post by Hotrod »

update-
New ignition leads fitted and car is running spot on, if fact better than ever. The leads must have been well past there sell by date.
Just for info. Due to the high voltage, If a lead breaks down, the spark will track down its secondary wiring causing it to get hot and arc, hence my melted one.
I also found the 3rd lead had arcing burn marks as well so I’m surprised it ran at all.

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Re: Ignition leads

Post by MRHAPPY62 »

Well done :clapping: Glad you got it sorted :yahoo:
The old leads were probably 30 years old so due replacing :)
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Re: Ignition leads

Post by MR2DI4 »

Genuine Toyota leads have the date of manufacture printed on them in the form of just the year. My old 1990 set blew one lead immediately when I increased the boost. New set getting pretty old at 2008 now as well but the car hardly gets driven.

Move to fine wire iridium plugs and this helps the leads from breakdown as it lowers the peak Voltage required to jump the plug gap. High boost is really nasty, the spark will actually jump inside the plug well rather than the plug from about 8psi once the insulation has failed.

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Re: Ignition leads

Post by Wheelnut »

Best place to get leads from? I bought a set of eBay, they were an inch short all round.
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Re: Ignition leads

Post by jimi »

TCBparts are reliable & stock good quality parts. https://www.tcbparts.co.uk/
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Re: Ignition leads

Post by Wheelnut »

Thanks for info.

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Re: Ignition leads

Post by David00 »

I'm looking for an HT lead set for a SW20/3SGE.

Paul at TCB tells me that he thinks the shielding on the leads he sells is thicker than OEM Yazaki parts. So they probably won't fit through the plastic shroud and retaining clips.

Has anyone bought after-market parts that were an exact match for the originals pls?
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Re: Ignition leads

Post by MR2DI4 »

Is Toyota in the UK really bad for parts ? I always call them first over here in NZ.

Seldom worth using crappy aftermarket parts.

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Re: Ignition leads

Post by David00 »

AFAIK Yazaki (the OEM) stopped manufacturing HT leads for the MR2 many years ago. I've always assumed that any "new" OEM parts are going to be old with the sheathing degraded over time even in a plastic bag in a store room. If anyone knows differently pls say so.

Most HT leads sold for the MR2 are after-market. There are just different levels of quality, from well known high end manufacturers to cheap copies.

You can find a wide range of replacements parts online. But it's hard to figure out which are a good fit - and usually the suppliers can't help as they don't know exactly what the lead lengths should be for a particular engine. So their part is compatible - but not exact.

Some owners have modified their cars to the extent that commonly available 8mm HT leads are fine. I'm trying to keep mine as original. Hence why I'm asking if anyone has bought parts that were a good fit.

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Re: Ignition leads

Post by Wheelnut »

What are the commonly used leads? Is this a length of copper cored cut to fit, can you get the original caps off?
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Re: Ignition leads

Post by SonicSW20 »

MR2DI4 wrote: 29/11/21 6:22 Is Toyota in the UK really bad for parts ? I always call them first over here in NZ.

Seldom worth using crappy aftermarket parts.
Their pricing is very hit and miss which puts people off. Some stuff is well priced and about in line with pricing elsewhere in the world, other parts are significantly cheaper if you import from Japan or the UAE (I assume Toyota have a large warehouse there) even after paying shipping any any due taxes.
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Re: Ignition leads

Post by nick »

MAGNACOR is the go to aftermarket place, but not cheap
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Re: Ignition leads

Post by jimi »

nick wrote: 02/12/21 12:37 MAGNACOR is the go to aftermarket place, but not cheap
Magnecor ;) http://www.magnecor.co.uk/default.asp
However you will get differing opinions on Magnecor leads https://www.mr2oc.co.uk/forum/search.ht ... mit=Search
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