VAF REFERENCE VOLTAGE

[ALFAMAF]

Pin,

Yes\ - I have used the supply which is the top of the VAF resistor divider chain.
To get the car going I have initially used a 1K potentiometer so I can adjust the reference voltage easily. Also this is useful in easily enriching the car for a cold start until it is all sorted. My guess is that the L Jetronic looks at the difference between the reference voltage and the VAF output, the greater the difference is the leaner it will be - ie at full air flow VAF = Ref voltage and thid is the richest it can deliver. So I can then understand how decreasing the Ref voltage will enable the ECU to deliver more fuel.

I have done some other measurements that may be of interest. Basically I have plotted the ECU injector pulse width at various RPM V's VAF voltage.This was done with a 220ohm resistor in the ECU temp sense circuit to simulate a warm engine. The measurements are a bit fluffy but the general relationship can be seen

Cheers
Doug