[Milehighxr]

I have a big VAM and 8UA(this an EEC that ran this size VAM) in my XR. Car has been running rich since last passing smog in 2021. I have no codes for the VAM, just a code for running rich no other continuous codes related to smog. The VAM sweeps nicely from 0-4.5 volts with my analog volt meter, no hitches, hiccups, or dead spots.

What voltage should I see at idle between VAF and SIGRTN? When I start the car with the breakout box(BoB hereafter) connected, looking at VAF and SIGRTN I have 1.45v. I went around and looked inside the VAM and the vane is 1" off of it's rubber stop. Blip the throttle a little and the voltage settles down at 1.17v and the vane is at .875" off of the rubber stop. I can smell that she is running very rich at this point.

Without knowing what the spring tension should be, or having any way of measuring CFMs I can't say for sure this VAM is worn out or misadjusted. I have never opened it to fiddle with the spring, and it does not appear to have been opened by prior owner.

[NigelM]

Your readings look proper to me so it doesn't appear you've found the rich condition.

Look at the usual stuff: Fuel pressure, leaking injector(s), install a new oxygen sensor (it could be giving incorrect readings due to fouling, contamination, etc.), unplug the PCV valve from the crankcase tube (leave it connected to the manifold side!) and let it suck outside air - and see if the code clears. If Yes, then change you engine oil as it appears to have too much fuel in it.

Make one change at a time, retest.

[dan_xr4]

My car has a high idle between 1250 RPM and 1500 RPM. My Mass Air Flow sensor indicates between 0.9 #/min and 1.2 #/min of air flow at idle.

For the Vane Air Meter 1.17 Volts is 13.1 CFM which converts to 0.91 #/min of air at 25 in Hg and 70 degF.
For the Vane Air Meter 1.45 Volts is 17.3 CFM which converts to 1.20 #/min of air at 25 in Hg and 70 degF.

For the BAP sensor 25 in Hg = 144.2 Hz
For the VAT sensor 70 degF = 3.05 Volts

At idle your Vane Air Meter reads about the same as my Mass Air Flow meter. If at idle your fuel system is not able to stay closed loop with the oxygen sensor switching then maybe the reason is not the Vane Air Meter.

If you are close to getting closed loop fuel control at idle you can adjust the Vane Air Meter bypass. The Vane Air Meter has a bypass passage. Increasing the bypass flow should reduce the Vane Air Meter signal at idle.

[Milehighxr]

Your readings look proper to me so it doesn't appear you've found the rich condition.

Look at the usual stuff: Fuel pressure, leaking injector(s), install a new oxygen sensor (it could be giving incorrect readings due to fouling, contamination, etc.), unplug the PCV valve from the crankcase tube (leave it connected to the manifold side!)  and let it suck outside air - and see if the code clears. If Yes, then change you engine oil as it appears to have too much fuel in it.

Make one change at a time, retest.

Nigel, PCV is probably one area I haven't looked at other than with propane/starting fluid to look for vac leaks. Fuel pressure is good, injectors do not leak. O2 was new when I started this process back in Sept/Oct. Car is currently not driven daily due to failed smog check. I believe I changed engine oil before attempting smog, have to look at log book.

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My car has a high idle between 1250 RPM and 1500 RPM. My Mass Air Flow sensor indicates between 0.9 #/min and 1.2 #/min of air flow at idle.

For the Vane Air Meter 1.17 Volts is 13.1 CFM which converts to 0.91 #/min of air at 25 in Hg and 70 degF.
For the Vane Air Meter 1.45 Volts is 17.3 CFM which converts to 1.20 #/min of air at 25 in Hg and 70 degF.

For the BAP sensor 25 in Hg = 144.2 Hz
For the VAT sensor 70 degF = 3.05 Volts

At idle your Vane Air Meter reads about the same as my Mass Air Flow meter. If at idle your fuel system is not able to stay closed loop with the oxygen sensor switching then maybe the reason is not the Vane Air Meter.

If you are close to getting closed loop fuel control at idle you can adjust the Vane Air Meter bypass. The Vane Air Meter has a bypass passage. Increasing the bypass flow should reduce the Vane Air Meter signal at idle.

I will have to look for this bypass passage. I've seen it referenced when I've been looking online about VAMs. I will have to rerun test to verify my RPM.

Gonna be awhile before I can get to it. I have been volunteered by "she who must be obeyed" to fix oil leaks on my oldest sons 06 Subaru Legacy GT.

[Dolphin1]

if you look at the pic, the plug in the lower left is the one you remove and there is a screw under it to adjust the bypass.

[dan_xr4]

Removal of the 0.5 inch "welch" plug requires drilling a hole in the plug and then using a screw in the plug to pull the plug out.

Does anyone have experience adjusting the bypass screw on the Vane Air Meter ? It should allow raising or lowering the air flow voltage at idle. Does anyone know the range of adjustment in terms of volts ?

[TurboRay]

Gonna be awhile before I can get to it. I have been volunteered by "she who must be obeyed" to fix oil leaks on my oldest sons 06 Subaru Legacy GT.

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LOL ~ In THAT case...... it might be QUITE a "while", Johnny, since that Scooby will probably need v/cov gaskets, cam seals &/or (sometimes) head gasks to cure the oil leaks! All are somewhat common in that "era" of Subarus. If h/gasks are needed, many have found removing the motor for access is easiest (especially on the 4-cam engines). <shrug>

[Milehighxr]

Gonna be awhile before I can get to it. I have been volunteered by "she who must be obeyed" to fix oil leaks on my oldest sons 06 Subaru Legacy GT.

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LOL ~ In THAT case...... it might be QUITE a "while", Johnny, since that Scooby will probably need v/cov gaskets, cam seals &/or (sometimes) head gasks to cure the oil leaks! All are somewhat common in that "era" of Subarus. If h/gasks are needed, many have found removing the motor for access is easiest (especially on the 4-cam engines). <shrug>

We did headgaskets on an 02 outback sohc back in 21 iirc, and I remember thinking "this isn't fun"...

The shop that found where "all" the leaks are wanted $2100 to reseal the entire engine, I have to look at the quote again and see if that included hedgaskets or not, but it seemed to indicate they would be pulling the engine and sealing the crankcase halves. See my new post re the xr...

[TurboRay]

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I've done a couple of "in-chassis" Scubie h/gask replacements, but I'll probably drop the engine if I ever do another one (unlikely, as I'm now somewhat "age-restricted"). The procedure I used was to unbolt the intake manifold and raise it 1-2 inches off the heads with a motorcycle tie-down (attached to the "propped" hood), plus drain the coolant, and remove the timing belt & sp/plugs. 

Raise the car, remove the front exh-pipe assy, disconnect the motor mounts, raise the motor slightly with a "screw stand", and suck it over to one side (till touching) with another motorcycle tie-down. Then, remove the valve cover and head on the opposite side. 

Even with the added room from pulling the motor to one side, SOME of the h/bolts cannot be completely withdrawn due to chassis interference and must be left loose in the head (make notes, so the new ones can be installed in the same positions before head replacement). Rinse and repeat on the other side. NOT FUN!!  <thumbdown>