Knock Sensor Ignition

I chose to upgrade my ignition system to a knock sensor system in order to take full advantage of the higher compression engine. I got my knock sensor ignition system off a 1986 Jetta Carat. Fitting the system to your car requires careful studying of wiring diagrams of the your car and the knock sensor system are necessary so that you can make the required modifications to your wiring harness.David's Volkswagen Page contains a wiring diagram for a knock sensor installation for a car with basic CIS fuel injection.If you choose to install a knock sensor system you will need the following.

• knock sensor distributor
  
• knock sensor
  
• knock sensor control unit
  
• the wiring harness for the system
  
• throttle body switches

Above are the throttle bodies (throttle plates and linkages removed), the one on the left is the stock throttle body, on the right is the knock sensor throttle body off of the A2 Jetta. Notice the switches on this throttle body, the switch on the left is the wide open throttle (WOT) switch and on the right is the closed throttle switch. If you have CIS-Lambda fuel injection, as I do, you will need to mount the full throttle enrichment switch as well, it can be stacked on top of the WOT switch. In some cases it may be necessary to re-position the bracket holding the switches so that the post on the throttle linkage(not shown) activates both switches or instead you could lengthen the post to achieve the same effect.

You've probably noticed the A2 throttle body is bigger than the stock throttle body, you need to enlarge the open on the intake manifold to match. The stock throttle body could be used if you mount the switches on it. In my opinion, it's just as easy to modify the intake manifold as it is to modify the stock throttle body so, why not upgrade to the bigger throttle body.

Since I first made this page, I've found an EXCELLECT write-up on this subject at Driversfound.com