924Board.org

[LJD@FSU]

i understand that my '81 931 has a digital ignition system. but why does the distributor use breaker points? can someone please explain this to me?

also, i understand that pertronix makes cheap, drop-in electic ignition upgrades to replace the points in other bosch distributors for around 70 bucks. does anyone know if one is available for the 931's or if our distributor is the same as in other VW/audi/porsche vehicles?

[Smoothie]

An '81 931 should have digital ignition control. There should be no points and no electronic ignition "hall sensor" in the distributor - also no vacuum advance/retard on it. There should be a crank sensor that generates timing from the flywheel. Are you sure the points in this distributor are wired up and functioning?

[LJD@FSU]

i have no idea as to the function of the distributor or how it is wired up because the car is not running yet (had to pull head due to bent valves from a thrown timing belt - putting things back together now, slowly). i don't know too much about ignition systems, but my buddy told me that the distibutor looked the almost the same as the distibutor in his '73 bmw 2002 including the points inside that he had recently replaced with an electronic unit. i have the little ignition control unit behind the driver's side headlight so i'm pretty confident that this should be the digital system, but with that funny distibutor with a vaccuum advance, i don't know what to make of it.

[John H]

If you've got a distributor with the two vacuum hoses out of it you don’t have a digital ignition distributor.
To check and see if you’ve got a digital controlled unit the following are visual clues.
1. Throttle body should be round not oval
2. Alloy tube going across the motor from turbo to throttle body should be an interference fit to the throttle body. If you’ve got rubber tube and hose clips then it’s a early model ignition system
3. Next look at the back of the motor on the top left side of the bell housing (if it’s in the USA it’s the drivers side) there should a small blue sensor with a gray coloured wire from it leading to the firewall. This is the flywheel sensor. (sensor is directly below or slightly to the drivers side of the heater valve).
4. In the centre console in front of the radio there should be an ignition control module this will have three connection to it. One is an air line(measuring boost), and the other two are the electrical connections. One is a is a 12 pin connector and the other is a three pin connector.

Anyway someone correct me if I’m wrong but didn’t early turbo’s have electronic ignition and no points?


[ This Message was edited by: John H on 2002-07-01 15:38 ]

[numbers]

Even if you have the oval throttle body, you will not have points in your distributor. To my knowledge, no 931 came with a breaker (points)type distributor.