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Pinched from the NGK website FAQ's. Thought I might remember detail better if it stays in here

Frequently Asked Questions

Q: When should I use a resistor spark plug?

A: NGK "R" or resistor spark plugs use a 5k ohm ceramic resistor in the spark plug to suppress ignition noise generated during sparking.

NGK strongly recommends using resistor spark plugs in any vehicle that uses on-board computer systems to monitor or control engine performance. This is because resistor spark plugs reduce electromagnetic interference with on-board electronics.

They are also recommended on any vehicle that has other on-board electronic systems such as engine-management computers, two-way radios, GPS systems, depth finders or whenever recommended by the manufacturer.

In fact, using a non-resistor plug in certain applications can actually cause the engine to suffer undesirable side effects such as an erratic idle, high-rpm misfire, engine run-on, power drop off at certain rpm levels and abnormal combustion.

and Aaron, if you are reading this from your cell at AMC, this may be what was wrong with your EJ20G'd Brumby !

great post. Will have to keep that in mind when i do plugs & leads.

Are there any special leads to get?

Funny, leads appear to be going through a change and offering lower resistance levels than before. I use and recommend the Eagle Products Eliminator series, 8.0mm black with sexy gold print. Plug ends are well made with a finger grip for removal, made west of Sydney (047) std code area, the box smells nice too The box claims it is a perfect partner with NGK!

dunno i used resisted in my rodeo for the simple purpose of it ran better... you wouldnt believe the difference a set of resisted plugs and low tension leads can make

OK you sold me...I'll do it!

Resistor plugz & low tension leads

nachaluva wrote:OK you sold me...I'll do it!

Resistor plugz & low tension leads

haha definitly do next time your due to replace... its noticable under acceleration and general start up

Low tension leads?

Aren't they high tension?

Low resistance.

Typically 50-100 ohms per foot for good spiral wire.

Normal silicon suppression lead is 3000 - 8000 ohms per foot.

^^^ what he said ^^^

I had a diagnostic ride in a standard looking Brumby - apart from the 3" tail pipe.
Oh, and under the bonnet was a a little non standard....



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The indash ECU readout from the MTX8 was indicating the temps and fuel trims etc and just within a few degrees of optimal operating temp the 16psi boosted EJ20G had weird power issues. It only took a few degrees either side of optimal op temp not to do it. Owner squirmed a little at the thought of new coils as he had already fitted used. I think engine had to be lifted off mounts to access plugs.



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I never got to learn of any resolution - owner got locked up.

The explain above reads just like its symptoms

OK . Now that I have fitted resistor plugs BCPR6ES-11 in my EA82TS I find this in the Australian Supplement of the handbook



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Next time I will be buying BCP6ES-11

Yeah early EJ20G coils are well known for being troublesome. Most opt for a remote bosch coil and lead setup.

Funny things spark plugs, my old man bought an MY97 forester brand new after first service ran terrible, took it back to the dealer, asked what they did, they said nothing but oil & plugs, etc. He then read the manual and from memory it said something like 'use ONLY champion plugs', he changed the dealer fitted NGK's to champs and ran like a charm again! Funny aye, and obviously only some EJ20's as Ive had some plugs that were branded both 'NGK' and 'STI'

early commonwhores do the same from VN to VT if you dont run GM plugs or the nippon denso equal