AAX value - disabling

[garyinwestoz]

Im getting sick of my Auxiallary air valve not working properly and having a cold start idle of 2000 RPM.

Is there any way to disable this thing - it really doesn't get that cold out west here to need such a thing (not) working all the time.

I've got the jules verne system under the air intake.

chow

[Mike W.]

Sure, you can bypass it, just connect the two air hoses running to it. You might want to check timing and fuel pressure first, cold idle is very affected by those two things.

[T.Hanson]

Where to start. I am blessed, cursed having a '79 and '81 528i. The nemo and more modern aux air valves. For no reason the nemo I cleaned years ago works great, to know how the valve is supposed to work. Turn the key, engine starts, idle goes to 1800-2000, quickly drops to 1200 depending upon how (winter) cold the outside air.
The '81 modern valve version is now very expensive, if available, new. First step is reading the Aux air valve FAQ, and the complete theory of relativity.
As Mike writes, part of the problem may involve timing and fuel delivery. Adjusting timing involves reading and a friend to help with conveying the tach numbers while turning the distributor.
Testing the fuel pressure regulator,... read that FAQ. Find, buy a new one or hop on over to your auto parts store for the pressure tester, then read how to use it.
Check all the hoses. Mine have a few little cracks to the outside of the clamps. The hoses fit over slippery tapered nipples on the valve, want to push themselves on the valve. Tightening the hose clamps appears to work to seal off any vacuum leaks.
To check and clean the modern valve cover type it must be removed from the valve cover. That allows the liberal squirting of the rust killer, oil lube spray in the pot, compressed air to remove the excess oil and crud, and being able to see the valve wafer is turning freely, the hole is appearing.
Don't even think about fooling with any of this with the valve attached to the valve cover. Anticipate removing the teeny wire clip on the electrical connector with an Xacto knife blade tip. Wrap a rag around it. No matter how careful, the 37 year old connector is so brittle from heat, the odds are massive a part of it will break off. With luck the teeny wire clip will not fly into the dark abyss of the engine compartment, and the part of the connector that broke off will not effect it being reconnected. If so, we will be involved in ordering a new connector and learning how to solder the wires, cover the connection with the little black wire cover tube.
Fooling with the weenie ass 7mm nut attached to the bolt on the valve wafer that rotates with heat open and closed, to adjust the cold idle,...
The nut will not turn loose enough for any adjustment unless an open end wrench is used. No standard socket or box end will work. Once the nut and washer are completely removed, the little bolt can be carefully moved in/out to check the wafer is rotating.
All of some stupid 3/8 ", that makes no sense for adjusting anything. " Start the car, quickly move the adjustment bolt (a freckle fart) in / out to achieve cold 1200 rpm."
Who wrote that ? It can't be done. There is no way to easily move the bolt in/out in the little slot with the nut, washer on it. Not with the valve mounted on the valve cover. Not while leaning over the fender, a little screwdriver or box wrench on the bolt pushing, pulling, with the other hand on the open end 7mm wrench tightening. To some fine tune place in the 3/8 " slot. There is ? Come on over and show me.
Instead, I am into the endless stubborn battle. The valve is clean, working. Set it all the way away from the valve...
And then find a way to see the big brass idle screw in the throttle body under all the wires, tubes, and somehow fit a screwdriver in the slot, to adjust that screw, idle rpm, cold,...
Because it turns out the aux air adjustment is effected by the throttle body needle setting, and probably the timing, fuel pressure, temp sensors, tire pressures and muffler bearing condition needing testing.

[Lock]

My Jules Verne sometimes works, sometimes doesn't. I'd like to replace it with the electronic version, but not at $300+ for a new one (or a questionable used one).
I'm going to try and replace it with a bimetallic strip idle air valve from an 80s Japanese car, as they can be had for $30-40 on ebay and will be 'close enough'.

[T.Hanson]

Just for more hot air, my years of key turning in cold temperatures the aux air valve liked to start at 2000 rpm. Not for long, to drop gradually to 1200. No surging, zooming or dropping below,... to say 800 and blubbering as if to quit.
My war with the '81 version achieved that 2,000 rpm start routine today. When up to normal operating temperature the idle is 1200. I am happy. The war is over.

[garyinwestoz]

We have a rather mild to warm climate here - our minimum is something like 2 degrees C on a occasional cold morning in July or august after its rained for few days then have a clear night. currently its 26 dec c midday day and min 11 at sunrise.

my idle is very weird and erratic.
when cold it starts and idles over 2000 - forget putting it reverse. Once get moving- idle say at a stop sign etc will be like 900 rpm. Drive a bit further - stop again - idle goes up to 2000 - what the - the engine is warm!