A friend’s Wasserboxer VeWanagon with Digifant (‘90) is being a poo and running very rich. So rich, in fact, that it’s running around with the vacuum line to the fuel regulator disconnected for extra air(!), and if connected, it chokes itself out. It also chokes itself out when the hole is merely blocked, and the regulator being connected doesn’t help at all.

I have checked to see what it does with the low idle enrichment switch disconnected, with the idle air control disconnected*, and the temp sending unit is new, as is the fuel regulator.

I have tasked the owner with doing an O2 sensor, and multimeter-checking the (new) temp sensor and the airflow and air temp sensor unit, since he has specs for it. We will also check the hall effect sensor on the dizzy and its connections, because they have been spliced(!) dodgily in the past, other than ground. Can’t see why that would be it, but it’s there...

Any other ideas?

*Yeah, with running rich at high throttle as well as low, wasn’t going to be it, but a boy can dream.