Hi everyone!
I've been having quite a nasty problem with my 1984 Volvo 740, engine B 230 K (electronic ignition with carbs). Just about a minute after I start the engine there seems to come from somewhere a signal messing up the ignition advance timing and keeping it erratic even at idle. I've tried replacing practically every part of the ignition system including the Hall effect distributor, the control module and the amplifier, as well as most of the sensors. It just won't work.

So, what I'm planning now is eliminating the whole control module and all the sensors that might be causing the trouble, by fitting an ignition amplifier which receives the signal from the Hall sensor directly and does not utilize a control module. Such an amplifier is mounted for example on VW Golf II, 1986->, EV engine (K Jetronic with completely separated ignition from ECM). In this particular model there are no other sensors or sources of information that could alter the ignition timing but the Hall sensor itself.

What I am wondering is, is the Hall sensor mounted in the Volvo distributor suitable to work with other types of ignition amplifiers, bearing in mind that it is originally connected to the ECM and not to the amplifier. The supply voltage of both Hall sensors is 12V and i'm not sure about the voltage that comes from the amplifier (resp. ECM) to the Hall sensor middle connection. (The one which sends the pulses).

And something else. Are the advance adjustments by higher RPM made by the ignition amplifier when there is no mechanical advance system in the distributor?

Thanks!