I have now taken off the fuel distributor and cleaned it. It was dirty on the outside but clean on the inside. The air flow sensor plate moves as described as does the piston in the fuel distributor.
The rubber gasket sealing the fuel distributor to the intake was damaged. A chunk of it was missing, maybe 1/12th of the circumference. I have replaced this gasket.
I re-took the fuel pressure readings, according to the Bosch K-Jetronic Service Manual. It has checking the WUR first. Those readings are:
control pressure cold, no vacuum: 2 bar (spec is 2.4-2.8 bar at 24.4deg C no vacuum; spec is 1.8 - 2.2bar with vacuum)
control pressure warm, no vacuum: 2.7bar (spec is 3.4 to 3.8 bar; spec is 3.4 to 3.8bar with vacuum [no change])
When you get bad readings for the cold test, its says to check:
* fuel delivery to control pressure circuit (60 sec -> 165g = .232 liter/minute: ok)
* fuel return (not checked as this would cause a "too high" pressure, not too low)
* warm-up regulator defective
When you get low readings for the warm test, it says to check:
* no current to warm-up regulator (not sure how to check current)
* voltage at WUR too low (I saw 11-12v on my needle, spec is 11.5v)
* fuel delivery at WUR too low (measured ok above)
* warm-up regulator defective
Of course, all of these measurements depend on good fuel pressure and flow. The flow measured 1100ml after 30 sec at the fuel accumulator. The system pressure is 66psi/4.55bar between the fuel distributor and the WUR (spec 4.5 to 5.2 bar). Those are in spec, but the pressure is at the lower end.
This seems to point to a bad WUR. Any thoughts?
WUR - fuel pressure gauge connected
Fuel distributor, all injector lines removed, fuel pressure gauge connected
