5 replies to this topic

[minimowta]

I tested the resistance of my ht leads the other day and got 2kohms for the shorter ones (to cyls 2 & 3) and 3kohms for the longer ones (to 1 & 4). Is this about right? I read on this forum that high res leads are about 5kohms but can't find any figures for the low res leads which we should be using on our injection engines. Obviously I'm getting lower resistances but is it low enough?

Cheers

[Ethel]

They sound ok to me, a resistor plug is about 1kohm. Any more than that has little benefit, but is till going to have much less effect than the plug gap itself. Higher resistances mean the spark will be a very tiny bit weaker but last a bit longer.

[minimowta]

They sound ok to me, a resistor plug is about 1kohm. Any more than that has little benefit, but is till going to have much less effect than the plug gap itself. Higher resistances mean the spark will be a very tiny bit weaker but last a bit longer.

Thanks Ethel. I thought the resistive plugs had a greater resistance than that I've read on these hallowed threads that low res leads have to go with with high res plugs and high res leads with low res plugs. I would like to know if my leads, although quite new, are right. If the resistor plug is 1kohm I've got the wrong leads!

Cheers

[orcadian]

Hi Minimowta, smee again,

Just whizzed out to the garage to check on my MPI leads, here are the results from the Orkney Jury:


lead 1 - 5.33K

lead 2 - 3.86K

lead 3 - 3.93K

lead 4 - 5.86K

These are the original leads which came with the damaged '99 sportpack which I bought in 2000 with only 5000 miles and broke to shove in the Clubman estate. No other engine mods and completed the IMM 2010 trip without missing a beat, even in some very heavy rain on the Autobahns. Now approaching 9000 miles in total. Where next in this long running saga?

[minimowta]

Hi Minimowta, smee again,

Just whizzed out to the garage to check on my MPI leads, here are the results from the Orkney Jury:


lead 1 - 5.33K

lead 2 - 3.86K

lead 3 - 3.93K

lead 4 - 5.86K

These are the original leads which came with the damaged '99 sportpack which I bought in 2000 with only 5000 miles and broke to shove in the Clubman estate. No other engine mods and completed the IMM 2010 trip without missing a beat, even in some very heavy rain on the Autobahns. Now approaching 9000 miles in total. Where next in this long running saga?

Thanks orcadian.

Looks like my leads are ok then. I took a couple of plus out and tested those one was 4.3kohm and the other was 4.1 - 'bout what I was expecting so all good there. Where next............ not sure now, garage checked the lambda sensor on Thursday and that was OK.

Cheers

[Ethel]

NGK's site says their plugs use 5k resistors - too many numbers in my head from trying to work out my own ignition. Leads will obviously vary a fair bit but 10-20kohms/metre is a fair bet for conventional carbon leads.