11 replies to this topic

[dpryszku]

 

Hello

Thanks to the great Sprocket tutorial i fixed today a rich condition of my 50k miles Balmoral 1275 SPI.
All capilaries, tube, fuel trap air sensor has been replaced. no more missfire, stalling and black spluks.
During this fix i did a bit of cleanning and had a closer look a the Air Housing Flap.
The flap is moving without problem and returns to its open defaut position thanks to the spring.

At startup the flap closes imediadtly that i think is normal.

After 20 miles run i had aother look while the car was still running, and the flap was still closed.

I check the behaviour of the flap by removing the yellow tube; The flap goes immediatly on open position. As soon a the yellow tube is back in place, the flap goes in close position.

As i thing the car was in cruising position i was expected that the flap was going to an open position.

am i wrong ?

what controls the vaccum on the yellow tube ?

Thanks for any clues.

DAViD
 

 

[IainStallard]

I've disconnected my air flap and it's always open (look into the filter from the front). When I connect it back up again and run the engine from cold, it's closed (open to the manifold) however once up to temp, It closes off the hole to the manifold and opens to fresh air from the front instead

[dpryszku]

Thanks for this answer.
I thought this was the correct behaviour.

Any idea of the mecahnims that control the vaccum to open/close this Flap.

Do you always run air flap disconnected (open to fresh air) ?

 

DAviD

[IainStallard]

Thanks for this answer.
I thought this was the correct behaviour.
Any idea of the mecahnims that control the vaccum to open/close this Flap.
Do you always run air flap disconnected (open to fresh air) ?
 
DAviD

I think the blue (I think) coloured valve in the air box shuts off the vacuum to the air flap as the temperature rises, meaning the flap stays open to fresh air instead.

I always run with it open yo fresh air as I had so many problems with mine to air leaks. Wouldn't recommend it in winter though

[eero]

Sounds like the vacuum is constantly getting to the flap.

 

Make sure the yellow tube is not directly connected to the inlet housing - it goes to the thermac switch on the underside of the air cleaner. Though it's probably not long enough for this.

 

Other than that - the thermac switch might be faulty and stays open. First - check it and give it a clean, might be some muck on there insulating the sensor. Other than that you would need to replace it, but unfortunately it's a discontinued part. Maybe second hand with entire housing assembly or there might be an alternative out there somewhere.

 

I currently run mine open all the time, cause the vacuum hose broke. Should be fine in summer conditions, but in colder weather engine might struggle when cold, because air is not heated up as much and the fuel does not burn as good.

 

EDIT: when disconnecting the vacuum to keep the flap open, remember to plug the hose, otherwise you'll lose vacuum and the ECU will mess up the mixture.

Edited by eero, 15 September 2013 - 04:46 PM.

[jaydee]

iirc they have a lifespan and need replacement after a while

[dpryszku]

Thanks for all this answers.

The yellow tube is connected underside of the air cleaner close to the red tube.
eero where is the thermac switch located ? On the flap sytem or on the air housing ?

 

Thanks for your help

DAviD
 

[IainStallard]

The thermac switch is the blue coloured bit where the red and yellow pipe meet on the airbox

[eero]

The thermac switch is the blue coloured bit where the red and yellow pipe meet on the airbox

 

Ditto.

[xrocketengineer]

The Thermac vacuum switch was very common on General Motors cars in the US in the 70's and 80's. There were several different types. A new replacement is hard to find, however there are some on Ebay US but I am not sure if they are exactly the same as the one for the Mini SPI.

 

http://www.ebay.com/...4c21729&vxp=mtr

 

http://www.ebay.com/...7dfe045&vxp=mtr

[eero]

The Thermac vacuum switch was very common on General Motors cars in the US in the 70's and 80's. There were several different types. A new replacement is hard to find, however there are some on Ebay US but I am not sure if they are exactly the same as the one for the Mini SPI.

 

http://www.ebay.com/...4c21729&vxp=mtr

 

http://www.ebay.com/...7dfe045&vxp=mtr

 

At first glance seem about right. Haven't examined the one on the Mini close enough to confirm.

[dpryszku]

Thanks to all for your answers.

I ll have a look at it next week end.

DAViD