I wrote about my recent misfiring episode on another thread, but I thought I would pass on what I discovered today.
My Stag has been running well up until recently, with the HT leads I fitted 7 years, 26,000 miles ago. These were new items bought from a well-respected supplier of Stag parts. Following the work to fit a reconditioned distributor and new electronic ignition, it began suffering from a misfire under load. This disappeared when I swapped the full set of HT leads with the old ones I took off 7 years ago and threw into a box of spares. I have since ordered another new set which should be with me in a couple of days.
Today, curiosity got the better of me, so I did some testing of the "faulty" lead set using a multimeter. Of the 9 leads (including the king lead) 5 were showing open circuit with my meter set on 20kOhm. The other three were around 12kOhm. I then checked the 9 old leads which I fitted on Sunday. One of these was also showing open circuit, with the remaining 8 showing between 7 and 12kOhm, depending on length. I have now replaced the open circuit lead with one of the good ones from the "faulty" set.
I am no electrical expert, but how the engine ran at all with 5 apparently faulty leads I don't know. I guess the high voltage was enough to overcome the broken leads up to a point, but disturbing them during the dizzy replacement was enough to tip them over the edge.
If my findings are relevant, you may want to check the leads on your car as all may not be as good as it seems. I don't know if the figures I've obtained are healthy, or how they compare with so-called high performance leads. Perhaps someone could enlighten me. I do know that I shall be keen to test the new leads when they arrive and before I fit them, for comparison.
My Stag has been running well up until recently, with the HT leads I fitted 7 years, 26,000 miles ago. These were new items bought from a well-respected supplier of Stag parts. Following the work to fit a reconditioned distributor and new electronic ignition, it began suffering from a misfire under load. This disappeared when I swapped the full set of HT leads with the old ones I took off 7 years ago and threw into a box of spares. I have since ordered another new set which should be with me in a couple of days.
Today, curiosity got the better of me, so I did some testing of the "faulty" lead set using a multimeter. Of the 9 leads (including the king lead) 5 were showing open circuit with my meter set on 20kOhm. The other three were around 12kOhm. I then checked the 9 old leads which I fitted on Sunday. One of these was also showing open circuit, with the remaining 8 showing between 7 and 12kOhm, depending on length. I have now replaced the open circuit lead with one of the good ones from the "faulty" set.
I am no electrical expert, but how the engine ran at all with 5 apparently faulty leads I don't know. I guess the high voltage was enough to overcome the broken leads up to a point, but disturbing them during the dizzy replacement was enough to tip them over the edge.
If my findings are relevant, you may want to check the leads on your car as all may not be as good as it seems. I don't know if the figures I've obtained are healthy, or how they compare with so-called high performance leads. Perhaps someone could enlighten me. I do know that I shall be keen to test the new leads when they arrive and before I fit them, for comparison.
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