View Full Version : Will worn plugs/wires take the spark from the timing light?

08-18-2004, 11:07 AM
1993 auto SC.

Hey guys!

Working on a tbird I recently bought, this one has sat awhile..

Anyways, I hooked the timing light to the plug wires, and no light on one of them...

I remove a plug from the coil pack, and no change, and no spark trying to jump to it like the other wires did...

From this firing order it is numbner 4 wire that doesnt give any spark...

It is intermittent, becasue when I warm it up, and rev it kinda high a few good times, the CEL goes away, and it runs a lot better.... Power also seems OK...

I sometimes see a check engine light, but I can't seem to get a decent code out of it. I get the 111 111 and then it goes on with a random series of blinks I need to try keep tryng to cipher...I can never read those darn blips and blinks :mad: Who's got some tips on reading the blinks??? Cause I always to it 8-10 times and give up... or the codes go away...

I was just wondering it the coil pack is likely bad, or if this could be caused by the DIS.

Am I likely to screw my coil pack up if I borrow one form my other good running bird? Or possibly the DIS module?

Thanks guys!

08-18-2004, 03:56 PM
A bad coil pack will loose a spark on two cylinders since there are only 3 coils, and there are 6 cylinders.

So if you are only missing spark on one cylinder start with checking that the sparkplug is good. The wire is good. Then check the harness connections for the coil pack are good. then check the connections at the DIS.

Last but not least would be a bad DIS.

08-18-2004, 04:16 PM
Wouldn't the spark still try and jump to the plug wire, even if the sparkplug it bad?

By the way, if you wiggle it and such. you can make it fire the timing light.

Could this just be bad wires?

I sent him to AutoZoo with the DIS to get it tested...

Maybe I should tell him to pick up some plug wires, and plugs...

08-18-2004, 06:07 PM
It takes completion of the electrical circuit to flow current for your lamp to pickup the inductive energy. If the plug is broken in a specific way, it can't flow the power from the plug wire. And it may not even be grounded anymore, thus no current flow, and no inductive signal.

The auto part store should have something called an Air Gap spark plug tester. This type of tester works best for DIS systems as it requires a fairly high voltage (which DIS systems provide) to jump a gap. If you pick one of those up and hook it to the spark plug wire you can see if any spark is coming out.

When you say "wiggled it" do you mean the spark plug wire? Wiggled it at what end? If down by the plug, then it's pretty suspicious and may not be the DIS.