Are aftermarket MSD, Moroso, Taylor spiral core plug wires known to cause problems with false triggering of the Merc knock sensors? I have the stock Merc red supression wires on my '99 502 Mag MPI's now and was going to replace them with MSD 8mm but then read some old posts that the spiral core wires cause EMI noise that the Merc knock sensors pick up. Being in the high performance automotive business we normaly use MSD or Moroso plug wire in the race cars and they have all sorts of electronics................EFI, digital ignition systems, timers, etc.......never have a problem as long as the wires are made up properly. After testing the resistance on the Merc wires and finding that it's very high, it seems that they are 7mm carbon core wires? We normally consider carbon core wires as cheap, fragile, Auto Zone style junk. I know that carbon core wires have very good EMI supression characteristics but in my world the spiral core wires are still considered a better performing wire overall. Are the Merc electronics that sensitive?

So are people using spiral core plug wires on '99 and later EFI engines without problems or do most stick with the stock Merc wires? Also is there any actual difference between the Merc "red" wires and the "blue" wires other than the color?

Thanks, Pat

Ive never had a prob with MSD on the boat and my race car motors,
http://apps.msdignition.com/wire_1.htm

Neither have I in any race cars but I never tried them in the boat. Never even thought about them being a possible problem until I did a search here and came up with some info that people where having problems with them triggering the knock sensors and retarding timing. So you have '99 or newer stock Merc EFI, ignitions, and electronics on your engines and use the MSD 8.5's with no problems?

Thanks, Pat

2001 500efi with stock dist and MSD box and coil and wires,6 summers.Only prob is the dist corroding on the inside.I coated it with dialetric grease and seems to be working now.

OK, thanks for the info.

Pat

Anybody else using MSD super conductor spiral steel core plug wires on a '99 and newer Merc EFI engine with all stock electronics and ignition system?

MSD wires are very good and should not cause any issues there, they have to work with far more sensitive electronics that we run in our race cars at this point...