UPDATE ; Bit long....
Installed a new 3 port Change-Over electronic valve. #A 000 540 98 97. During this test, ambient temperature was 73 F.
With engine start up cold, have a little fluttering of vac' signal to the AIR flow valve. Maybe 1/4 to 1/2 inch of vacuum.The Change Over valve is PWM by the ECU.
After engine warmed up, I ran a scanner check on the AIR 'on' and 'off' to see the results on the O2. With AIR 'off', O2 reads 180 mV to 790mV and ranging. With AIR 'on,' O2 drops to -4mV in around 15 seconds. On subsequent tests it drops rapidly to below 20mV in around 10 to 12 seconds. So this is a PASS for this test.
Monitoring the vac' to the AIR flow valve shows no readable vac' signal when AIR is scanner activated, although with extension vac' hose to my mouth, I feel a little fluttering pressure....this pressure/vac' is not enough to pull the flow valve diaphragm open to start AIR flow to the check valve ( Gulp Valve ).
If you apply 12 vdc to one pin on the change-over valve and rapidly touch the other pin to ground, vac' will slowly start jumping up to around 15 to 16 in and you can here the AIR/Kompressor pumping air into the exhaust and also watch the O2 drop to zero.
The Change-Over valve only passes vac' signal to the flow valve briefly when grounding the valve on and off quickly. To get vac' to 15 inches or better, on/off with jumper to ground and it builds up in 1/2 inch increments.......if you apply 12 vdc to inboard pin and ground the other pin, no va'c' will pass. Vac' only passes during the very brief period the ground pulls the Change Over valve 'on'. If it is 'off', no vac' passes and if it's held 'on,' no vac passes.......?
So, valve is only open during it's brief actuation period. Knowing this ...the ECU is pulsing this valve and should apply differing amounts of AIR flow...but watching for vac' signal during warm up, I didn't see any vac' signal going to the flow valve...
Code is not setting...so far, but I don't understand why I see no vac' signal to the flow valve during warm up. The scanner AIR Kompressor test shows the O2 dropping below 40mV so this test passes too.
Do I call this a fix or what ?
regards
dk
.