1) Disconnect the line from the ALDA that goes somewhere else.........probably to the transmission vacuum transducer. Make sure you only have ONE LINE from the overboost solenoid to the ALDA.

2) Drive the vehicle again with the gauge and see what the boost reads.

3) If still unsatisfactory, connect the Mityvac PRESSURE OUTPUT (on the top) to the ALDA. Pump it up to 15 psi and see how long it takes to bleed down. It might not hold pressure, but, it should take at least 8 seconds to bleed off. If you can't pump it up whatsoever, then the ALDA has an internal leak or has failed completely.

I still think the ALDA is not seeing the boost.........or not responding to the boost.........for some reason. Nothing else makes much sense.

With regard to the chicken or the egg............it's a bit of both.........you can't make full boost without fuel enrichment from the ALDA..........and you can't get fuel enrichment from the ALDA without some boost. 5-6 psi is typical of an engine with no fuel enrichment.

B.C.