The Subaru engines ECU has a tach output. The 1986-1991 Vanagon tach is not sensitive enough to pick up this signal.
Lucky for you we have a solution!
We have altered the circuitry in the tach unit to increase the sensitivity to the necessary level. At the same time, we've recalibrated the unit to read to 7,000 or 8,000 rpm to match our black or white guage face sets. This product can be installed in 1985-1991 Vanagons and works for all Subaru four cylinder engines.
Sold exchange for your tach unit. Core must be returned within 60 days for refund.