Ignition question, No longer thinking ignition.... Options

[1bwilson]

So I lend my jeep to a friend for a few weeks and go to drive the celica and find it running rough. After a bit of investigation Ive found the im getting a very small amount of spark from wire #4. So I did the usual swap plugs, new wires, new cap, new rotor...... Nothing, still a weak spark. So weak infact that its not even igniting fuel. Im not excited about the possibility of a pinched wire somewhere in the harness and im even less excited about the idea that I may have to hunt it down. So before I start pulling things apart let me go over what I know it isnt and hopefully someone will see light where I cannot.

out of the 3 mains (fuel,spark and air) Ive already figured out its the spark.

Its only happening on the #4 wire

Its not the plug, wire, distro cap, rotor as I have replaced them all.

I AM getting spark but its very weak and at times not there at all.

The old cap had burn/spark marks on the pins accept for the #4 one where it looked almost new.

I cant see any pinched wires but that doesnt mean something has worked itself loose some where out of view.

An option I have is running a MSD 6a ignition (if that would bypass my problem), Ive had one sitting on a shelf for almost 5 years and I have yet to install it. The only problem is I dont know how/which diagram to use for the install.

/discuss

This post has been edited by 1bwilson: Aug 29, 2008 - 7:04 PM

[Dr_Tweak]

Got your PM.

Since you've replaced all of the ignition parts on that side (dist cap, rotor, wires, plugs), so I would say that Bitter hit the nail on the head: Do a compression test.

An injector not firing will cause a dead cylinder as well, thought that's pretty rare.... put a mechanic's stethoscope on the injector and listen to see if it's clicking or not.

-Doc