HT Lead resistance - Results

[sk7ine man]

From my other post regarding my misfire, i have going through the basics to get down to what may be causing it. today i checked the Leads on the EVEN bank and here are the results:

CYL 2 : 5100 ohms
CYL 4 : 5000 ohms
CYL 6 : 4700 ohms
CYL 8 : 4000 ohms

HT lead 6 & 8 are shorter than 2 & 4, i know it affects resistance but should it be as much as 1kOhm? Or is that the underlaying problem? The leads are Magnecor KV85 8.5mm competition

[dirty boy]

sk7ine man said:

The leads are Magnecor KV85 8.5mm competition

<holds back on pressing the buy button>

[grovest]

Resistance will be proportional to length. This sugegsts 4 is 25% longer than 8 - is this the case?

[sk7ine man]

grovest said:

Resistance will be proportional to length. This sugegsts 4 is 25% longer than 8 - is this the case?

Lead 4 is 545mm
Lead 8 is 390mm

A bit more than 25% i think?

[sk7ine man]

Only removed the EVEN bank plug leads to check them and put them back in. Took the car for a spin around the block and after 1 minute of driving was only misfiring at low revs and hesitating.....about 30 secs later its misfiring through the rev range?! The leads look like they're ok by the test so could a faulty coil pack cause this?

[itiejim]

Definately

[jammy_basturd]

Maybe just one lead isn't seating properly on the plug?

[TT Tim]

The Magnacore leads can be a real pig to get seated on the plugs properly, especially the rear cylinders.

Worth a check, for the ammount of time you're spending it may be worth buying a 'spare' coil pack to eliminate that from the equasion.

Tim

[Gazzab]

I had a similiar prob on my 2nd cerb - APM sorted it out but it took a bit of working out - am sure he changed leads and coil packs.

[WIL35]

Mine did this when I replaced the leads, I checked the resistance and they were all fine. I had the same problem where it was ok when it was started up, but would miss once it had got a bit warmer. All I could assume was that when the leads got warm something happened to one of them that caused the problem. I put the old leads back on the suspect side and it was fine.

[Allandwf]

Just a resistance check won't tell you much, they can easily break down when current put through them.