Just Joined the Failed Spark Plug Wire Club
 

Driving home today (kind of a rainy, dampish evening), my Targa hiccupped at a stoplight and then, when pulling away, I could feel a weird hesitation/surge in power. It was clear it wasn't hitting on all cylinders all of the time.

When I got home, I popped the engine bay open and started studying the running engine. I could tell something subtly wasn't right, but I couldn't find anything amiss. I tried misting water around the distributor to see if I could get a light show, but again, nothing. I carefully (with a gloved hand) started poking and prodding ignition wires and I could hear things come and go. I could also hear the faint tic-tic-tic clicking of a spark jumping (like when you pull a plug to test for spark).

Finally, I saw what was going on -- a spark jumping from the No. 6 wire (the longest one) right near the distributor cap to the closest shielded ground wire (I'm running the stock shielded Beru ignition wires). I shut everything down, and removed the No. 6 plug to see if it was fouled from inactivity. It was clean so I put it back in. I then grabbed a long Beru wire from my stock of spares, hooked it up and fired the engine up. Night and day difference!

What I don't get is I can't see anything visibly wrong with the bad wire that would allow that spark to jump (a tiny crack in the insulation?). Weird.

Brian

If you have the wire out and bend it you many see tons of all these micro cracks.
If installed, sparks are best viewed at night. Check the other ones.
How old are the lines?

Get the right spark to jump and you can blow the air filter housing into bits.

What a Job!
 

I installed new plug wires all around today.

I bought bulk 7 mm spiral copper wire and the Beru M3 connectors that attach the plug wire to the Beru plug connector. The trouble is, Beru recommends a very, very expensive crimper to attach the M3 thread sleeve. That didn't fit my budget, so I made two tools using small steel blocks and a vice to crimp the end of the thread sleeve and the collar. This worked a treat, but the process of transferring the ground shield wires, heat shrinking, etc. was very slow. Not difficult, once I had my two crimping tools made, but just fussy. I started on this job this morning and finished this afternoon. I also replaced and re-soldered the coil wire (which was crispy as heck).

I saved a bunch of money doing it this way, but the trade-off is that it's not plug-and-play. However, I learned a lot about how the stock plug-wire sets are assembled.

Anyway, the car runs great with the "new" wires. By the way, thanks Zuffenhausen for putting the firing order label in the engine bay. Saves a lot of time and makes it easy to keep things accurate.

Brian

Brian do you have a picture of the tool you made?

Some guys are show-offs ! ..... :)

http://forums.pelicanparts.com/uploa...1303066271.jpg


From here--- > http://forums.pelicanparts.com/porsche-911-technical-forum/412613-upgraded-ignition-problems-check-your-spark-gap.html

Nothing fancy. For the larger sleeve crimp, I split an M7 nut (such that the flats are parallel with the vice jaws) with a Dremel after grinding the opposing points flat a bit. For the smaller crimp around the lower sleeve threaded part, I drilled a hole the size of the threaded part in some 3/16 steel stock that I then also split. I could then execute this crimp with my big channel-lock pliers.

Pelican "cgarr" made his own crimping tool as well. I'm not sure how he did it.

Brian