Any Advice, Part 2!

[Bob Meadows]

The hose to the valve should be a push fit:~
Generally a hose clip isn't required, if for some reason it is loose you could add one, or run a couple of turns around the spigot with insulation tape.

The important thing is that when the engine is cold the inner valve is open-as the car warms it should close.
You can lubricate the valve & spring as you push it from side to side.
The fitting can be easily removed and tested with a battery- bimetallic strip etc.
It does need to work on the car though as it gets power from an engine block fitting.
Bob.

[Chris152]

No joy, we ran it for 3 mins and it had resumed 'chug' mode! :-(

We took that hose off and took a pic of what's inside - is that the valve that we're looking at? If so, it looks to be closed, I'm assuming it should have still been open at the point that the engine was still warming up?

[Laird Scooby]

Originally Posted by Chris152

No joy, we ran it for 3 mins and it had resumed 'chug' mode! :-(

We took that hose off and took a pic of what's inside - is that the valve that we're looking at? If so, it looks to be closed, I'm assuming it should have still been open at the point that the engine was still warming up?

After 3 minutes it shouldn't be that far closed Chris, even on a warm day. You may have to replace the AAV, secondhand ones aren't that dear but first i'd suggest removing it, squirting in both ends with carb cleaner and using a long thin screwdriver to exercise the valve open and closed.
Give each end another good squirt, letting it soak for a minute or two then empty out and do the other end. Leave to dry while you find a self-sealing bag to put it in then leave it in the freezzer for an hour or two.
When you remove the valve from the freezer, check that it's fully open, if not you will have to renew/replace the valve.

The bimetallic strips inside them go weak with age, especially if they have been left dirty for some time.

[Chris152]

Thanks Dave - will brake cleaner do the same job? If not we'll pop out and get carb cleaner.

ps - Thanks Bob, we couldn't reach to fit a clip on the lower hose which was just as bad, so put a turn of insulation tape as you suggested.

[Laird Scooby]

Originally Posted by Chris152

Thanks Dave - will brake cleaner do the same job? If not we'll pop out and get carb cleaner.

ps - Thanks Bob, we couldn't reach to fit a clip on the lower hose which was just as bad, so put a turn of insulation tape as you suggested.

Brake cleaner should work too but if you can get carb cleaner, so much the better. Keep an eye on that insultaing tape, it has a nasty habit of becoming unravelled and being ingested by the engine. Better bet is to find some thin-walled tubing that just about goes over the stub then fitting the original hose over it.

[Chris152]

Off to the shop! :-)

[Bob Meadows]

Chris:~
You can get some adjustment on the valve by rotating the small screw next to the hose- limited though.
Can you do a battery connection test off the car? you should see the valve start to move slowly. This will tell you if the a/v is working or not.

If it is then the thermal time switch could be the fault: initially check that the electrical contacts are clean at both ends of the cable -follow the lead from the a/v back to the block fitting and clean.
You should be able to eliminate things by doing the above:

As already mentioned the internal metal strips can get weak- I've opened & bent these back to improve the valve movement -- The official consensus is that they can't be fixed!
(A faulty valve can give the difficult start conditions that you describe so best to eliminate this before moving on etc.)
Good Luck.
Bob.

[Laird Scooby]

Originally Posted by Bob Meadows

Chris:~
You can get some adjustment on the valve by rotating the small screw next to the hose- limited though.
Can you do a battery connection test off the car? you should see the valve start to move slowly. This will tell you if the a/v is working or not.

We already know it's working electrically, it starts normally then closes rapidly to cause the "chug-chug" Chris describes.


If it is then the thermal time switch could be the fault: initially check that the electrical contacts are clean at both ends of the cable -follow the lead from the a/v back to the block fitting and clean.

The thermotime switch isn't involved with the AAV at all, only the CSI - Cold Start Injector. The AAV is powered as soon as the ignition is switched on and off when the ignition is off.

You should be able to eliminate things by doing the above:

As already mentioned the internal metal strips can get weak- I've opened & bent these back to improve the valve movement -- The official consensus is that they can't be fixed!
(A faulty valve can give the difficult start conditions that you describe so best to eliminate this before moving on etc.)
Good Luck.
Bob.

Bending the bimetallic strip is only a short term measure as it will have bent itself over many years against dirt inside the valve and will return to its "new" position by itself in a relatively short time. It also weakens the bimetallic strip bending it back and can cause complete failure. Using the freezer method to ensure it's fully opening helps to bring it back to where it should be. If it doesn't fully open in a freezer after 1-2 hours, the strip is too weak to bend in service as it should to move the valve.

[Chris152]

Thanks both.

Dave - how dry does it need to be before going into the freezer? It's been sat 15 mins but still has carb cleaner on the internal surfaces.

Cheers

[Laird Scooby]

Originally Posted by Chris152

Thanks both.

Dave - how dry does it need to be before going into the freezer? It's been sat 15 mins but still has carb cleaner on the internal surfaces.

Cheers

Just give it a shake to get the majority of it out Chris, the carb cleaner shouldn't freeze but may have a tiny water content so eliminate most of it and you minimise any problems - certainly no worse than condensation in the inlet manifold/trunking/hoses after a long hot run anyway.