13BTOY

iTrader: (1)

I was under the hood today and decided to check my spark(I was bored). I used one of those spark plug wire break tester(I think thats what its called). Anyways youre suppose to run this up and down your spark plug wire to detect electrical current break in the wires. Theres a little glass window that shows how much spark is flowing through the wires. The stronger the spark the brighter it gets. I fired up the car and hooked it up to the leading wires and got nothing? Switched to the trailing and it was sparking nice and bright. I pulled the plug wire at the plug while the car was running to see if it was getting spark and it was. I held it close enough to make it arch to the plugs but it seemed weak. What would cause my leadings to have a weak spark? Coils, ignitors? No wonder my car seems low on power. By the way, I have checked the leading plugs for spark many times prior to today and they have always made my tester glow like crazy(strong spark).


Thanks, Ed

Jeff20B

iTrader: (13)

So it just started being weak? Maybe a bad coil or something. Please detail your ignition system because not very many of us will remember all the particulars of yours.

13BTOY

iTrader: (1)

Hey Jeff its me again. I just cant keep my hands off my car! LOL! Anyways I tried the MSD set up a couple of days ago if you remember and ended burning out my FC coil. It turns that I had a bad 6A. Anyways I switched back to my old set up prior to the FC coil which was your directfire. Noticed the difference right away. Much stronger than when I had the FC coil(my opinion). The car ran great! All of a sudden my leading sparks got weak and when I checked it like I mentioned in the above post I could not even get my spark tester to go off. I just finished checking the ignitors as per your intructions with the speaker(neat trick by the way) and they were good. I forget exactly how you check a coil so I couldnt test them. Care to remind me? PLEASE!

Thanks, Ed
On a side note all three coils are getting even power according to my voltmeter.

Jeff20B

iTrader: (13)

Have you checked the plugs lately? I was checking all sorts of things before noticing I had bad plugs. It was a core engine I rebuilt and the plugs in it looked good/clean. Heh, whoops.

Well, my idea came from having to test five used coils as efficiently as possible. I just sparked the coil through a spare plug wire into a plug held in a grounded vice grip. Each coil sparked into the air just fine. I've since installed them all and they all seem to work fine in running engines.

How much 'juice' are the coils and ignitors getting? Are they having to draw power through the key switch? I had as much as one volt drop through the ancient REPU wires, so I hooked up a Radio Shack 30 amp relay and it kept the wires from getting hot near the key. Check alt output voltage and then check ignitor/coil voltage with the engine running. Mine went from 14.0 at the alt to 13.10 at the ignitors. Now it's all up to alt output voltage.

13BTOY

iTrader: (1)

Jeff, thats close to what I'm getting. 14.55 at the alt and 13.70 at the coils and ignitors. Do I still need the relay? Anyways I put everything back last night and swap the plugs out with a set of old FC plugs I had lying around coz they were all black. To my surprise they were firing again? I suspect that my aluminum plate was not grounded properly when I switched back to the directfire therefore giving the leading ignitors a weak spark(makes sense) or it could be a combonation of not enough ground and old plugs. One way to find out. I guess I'm going to put the old plugs back in to check.

Thanks, Ed

Jeff20B

iTrader: (13)

Those two things you did helped me. I swapped out two of the bad plugs for FC leading plugs in the leading holes. It fired up within 3-4 seconds. Several months ago, one of my ignitor plates had a bad ground. I added a wire to it and a decent ground screw and the problem never came back.