308 QV WUR Issue/Odd problem?

Unplugging the AAV is like unplugging the WUR. Don't expect to see much if any diffeence. All the plug does is heat up the AAV slowly in case the engine warmth doesn't.

Pulll out the AAV and test it. The AAV helps the engine run faster and smoother while it is cold. If it is stuck shut your car may run rougher when it is cold.

You could even run your engine, go for a drive, and then pull the warm AAV. It should be closed. Now let it fully cool. It should be open.

 

** "The AAV helps the engine run faster and smoother while it is cold"
That's right, the AAV helps the engine run faster ! (when cold)- so when cold, mine runs very fast 2k rpm or so and stays fast throught warmup, without the AAV connector attached. I had to slow it down with a resister to heat the AAV more slowly.
**It sound like his AAV is stuck closed or partially closed, thus not enough air getting to the engine and a rich mixture.

 

The AAV does not affect the mixture. The AAV is a device that basically opens the throttle a little bit to rev up a cold engine. All of the AAV air is being metered by the CIS. It is absolutely not different from putting your foot a bit on the throttle pedal.

 

WUR heating element
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**This is a quote from Steve Magnusson, last June.
"The part on the right is the Auxillary Air Valve (AAV) -- it allows some extra air into the engine when cold (and it should not be eliminated IMO)".
http://74.86.28.138/~ferrari/forum/showthread.php?t=245672&highlight=AAV
It's also my personal experience, that if the AAV is closed when the engine is cold, the car runs rich, which seems to confirm that the AAV adds air during fast idle. I assumed that adding air, changes the mixture. (maybe I'm wrong) It definitely changes idle speed.

 

I think Steve can settle this but I am going to give a try, when the engine is cold, AAV lets in extra air the and WUR adds the extra fuel, so you needs both of them working if only one is working you either have the engine running rich or lean. This increases the engine RPM without the opening of throttle plate.

 

You are taking that quote a little out of context. It is true that the AAV allows extra air to enter the engine, but the air source for the AAV is downstream of the airflow metering plate -- so, when air is flowing thru the AAV, it draws the airflow metering plate down more and also (indirectly) adds fuel (as Brian said -- it is equivalent to opening the throttle plate). That thread was for a person who wanted to remove the AAV system -- bad idea.

If the engine was struggling to idle at a low RPM after cold start-up, this could cause the MAP to go to a high value (looking like high engine load) which might cause the WUR to (wrongly) add richness -- but does it really matter? "Struggling to idle at a low RPM after cold start-up" needs to be fixed regardless

 

*I was referring to cold start, fast idle only, (before fully warmed up). Thanks for the added explanation Steve. I've noticed that "during warm-up", if I block off the AAV, the car runs very rich and idle speed drops to(600-700rpm). With AAV open, it runs fast idle(1500rpm) and the "rich smell", is gone, so I assumed the air/fuel mixture was leaner, telling me that the AAV was adding more air than fuel "during warm-up". I'm still trying to master my understanding of the CIS.

 

As a basis to troubleshoot high or varying idle speed, make sure the little hose connecting to the top of the coolant expansion/recirculation tank is putting out a very healthy stream of coolant into the tank. The water outlet nipple at the other end of this small diameter hose gets badly plugged-up. This reduces or stops "fresh", hot coolant from recirculating in the tank which results in an overall lower temperature of the tank. Since the AAV is secured to the tank for the purpose of heat transfer it ends up getting less heat than it should and may not be able to completely close, or keep closed, the AAV via just the electrical heating element. This can be one cause of high or varying idle (a vacuum leak being the most likely other cause).

You can hear and see this stream of coolant quite well if you remove most of the coolant from the tank with a turkey baster. If there's not a strong stream shooting into the top half of the tank you've got a problem. Just make sure not to remove all the coolant in the tank for this test as you may introduce air into the system.

Incidentally, Euro 328's don't even have an electrical heating element in the AAV. All closure is due to coolant tank heat transferring to the AAV. Not sure about Euro QV's on this but I suspect it's the same.

 

**My problem was the heating element was closing the AAV too soon, causing a slow idle during warm-up. I've added a 3 ohm 3 watt resistor in series and it's much better now. (still experimenting with the correct value) I just needed to slow down the closing time, of the AAV, to maintain fast idle a little longer. The 3 ohm resistor drops the AAV heater voltage about 2 volts, to warm it up more slowly.

 

**Try cleaning it with wd-40 or equivalent and use a screwdriver to manually move the air slider back and forth, until it slides easily.

 

+1 the go to guy....

 

When cold the AAV should be very open, not 100% but far more that yours or you'll have a rich and slow cold idle.
See photo of mine when cool and when hot. Not perfect but better than yours.
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I would also be looking for consistency. If it doesn't open or close 100% but opens and closes the same amount each time you could compensate by adjusting the throttle body idle screw. But if it closes a different amount each time then your idle will always be different and random - definately not befitting a Ferrari!

 

FWIW

I looked through my Probst book last night. He as two different pictures of the AAV that open and close just like Spiderseeker's AAV. Not 100% open and not 100% closed.

 

Nice picture!!! It shows the part number on it. A google search shows 4 different AAV parts.

http://autoparts.thecarconnection.com/auto-parts/ferrari/cooling-system-auxiliary-valve

Ranging from $63 to $369.

What is the difference between these AAV parts to have such a huge price span?

I can't find a local store that carries one to look at it.

 

Would these devices have anything to do with warm temperature performance?

I've been chasing down a sputter in my cars midrange for a year. The car works great as it's warming up and pulls to redline once it's warm perfectly. Then almost like clockwork the car will sputter once the needle hits the halfway point. I feel like it may be vacuum related or something is closing/opening once a temperature switch directs it to do so.

Been through the ignition components already.

 

The AAV is down stream from the fuel metering so it does not affect the air-fuel mixture. It only bypasses the throttle to rev up the engine when it is cold. The WUR makes the mixture richer when the engine is cold and the AAV revs up the engine; so they work in junction.

The AAV is opened when cold and closes up when hot. It can be heated up by external temperature, as attached to the engine block, or by electricity with the internal bimetal to the connector. Each AAV has its thermal characteristics, how much it opens with temperature.

There appears to be two types of Bosch AAV for our 308/328 engines, one for the 2V and one for the QV/328.

Can somebody confirm this?:

Bosch 0280140129 appears to be the cross reference for the 2V models $83.99
Bosch 0280140229 appears to be the cross reference for the QV/328 models $
369.99

The 2V models have the AAV next to the air plenum; these appear to be heated by the engine block. The QV models have the AAV under the water reservoir, and appear to be heated with the water temperature (there is a steady stream of radiator fluid so the engine block temperature is the same as in the reservoir).

Does anybody have pictures of these two AAVs and their mounting? Why the big difference? I couldn’t find any Volvo, BMW, etc cross reference for the 129; it is not less expensive due to higher volume by being used in other vehicles.

Does anybody have the electrical schematics showing how the AAV is connected in a 2V and a QV?

 

Buying a used AAV is like buying a used thermostat. It may be a good replacement for a broken one, but it may still stick. I too am looking for a new replacement. For now, I'm starting the cold engine with my foot on the accelerator; the AAV only works during warm up.

Have you seen if the mouning of the 129 fits under our reservoirs? Per what I read, all it needs is a good thermal contact to the engine temperature and the electical connection. The air opening appears to be the same.