Aux air device..

[mrzigazaga]

Hi peeps.. This unit is the spare one i found in boot does anyone know what it is.. I know the AAD fixes to it as mine is, The guy that had it before me broke off the little housing with the two pipes coming out and the hoses that normally go through have been re-directed.. My AAD is functioning when i tested it off car..cleaned it and put back on.. Now because the hoses are missing would this mean that the AAD is not getting hot enough to close it because thats what it seems..I ran the car for an hour and it still didnt get hot to touch?

Edited by mrzigazaga on Saturday 4th September 19:45

[ihouston]

Is your car a 2.8i with an MFI Bosch injection system on it - as you device looks nothing like mine - my one is circular / conical in shape - completely different to the picture of yours.

[mrzigazaga]

Hi mate.. no its got K jetronic, This is what the AAD attaches to and does it heat the AAD as i cant see air being that hot.. This would explain why it isnt closing but is working when i tested it..

[jeff m]

I would guess that is called something like "aux air device mounting plate, the bit the water runs thro'"
A bit of a long name but any 280 person would know which bit you are after.
A pic below shows where it is (which will help, as I did not immeadiatly recognise it)
With regard to what heats the AAD. Water running thro this plate,the hoses are marked blue, it is also heater by a bimetal strip.
The orange hoses are the air ones.

[mrzigazaga]

Thanks jeff.. The blue ones are what have been re directed.. So the mounting plate has no hot water going through..therefore the AAD will not close.. Correct.
Dont say its been that all along.. could it.. would it.. should it.. Just a thought can the AAD be mounted to engine without that bit? would that work..

Edited by mrzigazaga on Saturday 4th September 19:54

[jeff m]

mrzigazaga said:

Thanks jeff.. The blue ones are what have been re directed.. So the mounting plate has no hot water going through..therefore the AAD will not close.. Correct.
Dont say its been that all along.. could it.. would it.. should it.. Just a thought can the AAD be mounted to engine without that bit? would that work..

Your logic is correct, but it may still close because of the bimetalstrip.
If your rpms are dropping after a minute or so, then it is closing.
If that is the case then you could omit the plate.....make sure the blue marked hoses are joined to maintain correct water flow....and bolt it directly to the plenum using one of the bolts that held the plate.

Not ideal, but it should work.
BUT if the bimetal strip ever gives out, loose wire, loose connecter.......you will have a high idle. On the bright side you will know exactly what the fault is

I'd give it a try, you can always put in a replacement mounting plate in later if someone comes up with one.

[mrzigazaga]

Thanks jeff. I did clean and try the one in boot.. ive got the other one to do now, To be honest it wasnt getting that hot even after idling for an hr..revs only dropped when fan kicked in so im definately going to try that tom.. The hoses have been put all together like a knot.. I will try to take some pics of it tom as it dont look right..

[jeff m]

Mark I just had a closer look at your pic.
Do you think that is fixable, from the pic it looks as though you could get that bit out with a an "easy out" an then put in a new fitting for a hose.

Just a thought I can't see the hole in the plate, but castings are nearly always female with fittings usually male.

[mrzigazaga]

Yes jeff, i was thinking that.. The big connection is on there its only the twin pipped bit..If they werent broken and just thread was gone i would of tried HT2000 as it is ally solder but has a 500deg lower melting point but a strength like a solid block..Will have to keep me eyes open..Thanks for the email regarding AAD thats helped sort it or eliminate one major factor..Sorry wouldnt happen to know where front jacking points are would you as ive a flat.. Cheers..M

Edited by mrzigazaga on Saturday 4th September 21:04

[MJG280]

When engine is warm squeeze the air pipe closed and see if the tickover reduces. If it does then that confirms that the AAD is the problem.

[mrzigazaga]

Thanks mjg.. will ave a go today if the big black cloud goes away...I really hope that this is the problem.. Im trying to stay positive but knowing my luck it wont be.. I even watched songs of praise this morning just to get on gods good side.. but i think hes aving none of it..

[ihouston]

Has nobody looked at the picture Mark has put up it looks nothing like the AAD on the Bosch K jetronic system to me the picture Grady put up is what it looks like - not sure what you have there or taken a picture of but it is not the AAD on the K Jectronic.

[jeff m]

ihouston said:

Has nobody looked at the picture Mark has put up it looks nothing like the AAD on the Bosch K jetronic system to me the picture Grady put up is what it looks like - not sure what you have there or taken a picture of but it is not the AAD on the K Jectronic.

It's the bit that the ADD bolts too, it has water running thro it to make the ADD operate.

[ihouston]

The Aux Air Valve does bolt to this plate the valve is a device to aid the engine when cold by opening a small port to increase the engines idle speed. The fast idle control is achieved by the port being held open by a bi metallic strip that when heated by its on heater element, or via natural heat soak from the engine , the port closes. The voltage supply to the air valve is the same as the feed to the fuel pump and the warm up regulator. If it is found that the idle speed will not reduce and that the speed is maintained artificially high when warm , clamp the rubber hose pipe between the air valve and the inlet manifold - if this action causes the engine revs to return to normal - the fault is a sticking valve
If this is the case you can try cleaning the valve and lubricating it.

Not sure this will be giving Mark all the problems he has.

[mrzigazaga]

Cheers chaps.. I did attach the AAD that i found in boot,cleaned and tested (worked), I removed the plate that holds it and bolted it straight to the Air chamber.. The big ally bit on engine.. It did partially close but i could still feel air rushing through.. It wasnt getting hot enough to close fully,I did clamp pipes at both ends and the revs did lower.
A bit of a result though when i changed the cooling hoses over i noticed that the guy who broke it obviously replaced it but broke that then found the fitting that is missing off of it now and used that to join three hoses together.. The thread has sheared off inside the hole,If i can get it out then i have the part to go in already...To be honest the car is running alot better that it did before i bought it...The flutter is not so prominent even when its hot..have to fix leak in mid sect as it blew off last week..Also got a flat front tyre, Do i use a trolley jack or are there jacking points... Sorry if its a dumbo but i couldnt see anything under there.. Thanks..zig

[MJG280]

My AAD hose is temporarily stopped up with a 15mm pipe that has a blanking piece on it.

The front tyre will be fun as you will have to drive the flat tyre up onto a piece of wood to get the chassis high enough to get a jack under. The best place at the front for a trolley jack is the front suspension crossmember situated between the wheels. There are no jacking points as in modern cars just points on the chassis that can take a jack safely.

Edited by MJG280 on Sunday 5th September 20:12

[mrzigazaga]

Cheers MJG..That does sound fun.. might have to call the rac out again as he had one that looked flat and low with a little plate on it..If all fails might have to do what youve done with AAD as this might not still be the issue although its running and sounding alot better.. Ta mate..