I am looking for a new set of spark plug wires for my 1989 4runner. Parts suppliers ask whether my 4runner was built before 4/89 or after. Mine was among the earlier 4runners in the 1989 model year, with a build date of 12/88. So far I’m finding that it is much easier to find wires for the later vehicles. I’m wondering what the difference is between the earlier and later style wires, and can I use the newer style wires? It looks like the later wires use the same distributor cap.

 

I think I have figured it out. It all has to do with the coil. 3VZE powered vehicles build from 4/89 had a different coil. Instead of the familiar cylindrical shaped coil, vehicles produced from 4/89 and on had a square shaped HEI (high energy ignition) coil that used a different spark wire. A couple of manufacturers offer a spark plug wire set that offers both types of coil wires, Including a set made by the Japanese OEM supplier Denso that can be purchased from rockauto.com So apparently the rest of the wires are interchangeable, with only the coil wires being different.

Just as a sidenote, I found a Denso oxygen sensor at rock auto for $62 which sells at my local NAPA auto parts store for $142! Same part number.

 

Take a measurement of resistance of the longest ignition wire and the coil wire to the cap. The FSM states that the value should be less than 2.3K ohms. For the two sets of Denso replacement wires I have purchased recently the coil wire is under 2K but the long one is always more than 2.3K. so cylinder #3 gets the long end of the stick! Food for thought.