Sticky Sad? Does It Need Cleaning?

[Fox 3]

As I understand it the SAD keep the revs up by adding more air and fuel to the TB for a few minutes when the engine is cold. Controlled by the coolant temperature?

 

Now, mine seems to be playing up, it holds the revs at 1800 for about twenty minutes - half an hour from starting, the water temperature rises quickly as normal but the SAD doesn't slow the revs until (it appears) the oil gets up to operating temperature.

 

When its lets the revs drop its sits happily at about 1k.

 

I'm imagining the SAD is gunked up and its sticking open, how do I go about cleaning it, if that's the problem?

[welshpug 1,666]

remove it and blast it through with brake or carb cleaner, but check that the black 2 pin plug is connected firstly.

 

The SAD is affected by 2 things, heat transfer from the Thermostat housing or water housing that its attached to, as well as a heating element (hence the 12v supply)

 

It doesn't have a direct control over any extra fuelling, it just allows additional air to be drawn in by the engine, which is metered by the AFM, hence the raised idle.

[Tom Fenton 1,548]

Check that it is getting a 12v power feed, the disc inside which rotates does so using a bi-mettalic spring that is heat sensitive. The SAD receives heat from conduction as it is bolted up against the thermostat housing, and also receives heat from a small heater coil inside, powered from the electrical plug on the back. If either the heater coil is bust, or it is not getting any power, this could explain why it takes so long to slow the idle speed down.

 

To test it take it off the car and give it a good clean out. Then connect a 12v and an earth to the pins on the elec plug, and look through the SAD. You should be able to watch the disc move round until the hole is blocked off, within a couple of minutes. If nothing happens with it off the car and 12v connected then the heater coil is knackered and you will need another SAD.

[Fox 3]

Fantastic guys!

 

I'll whip it off and check tonight.

 

Is the two pin 12v feed fed from the ECU then? Under what conditions does it supply the 12v feed, so I can check its powering up ok?

[welshpug 1,666]

its just an ignition switched 12v feed from the tachymetric relay, wire 18 which splits to 48 (SAD) 18A (AFM) 9 (ECU) 37 38 40 and 41 (Injectors)

Edited September 2, 2008 by welshpug

[Project205 0]

Hi,

 

I am interested to know when the power reaches the SAD plug, is it as soon as the car is started?

 

I have the idle problem whereby you start the car and it barely ticks over, then once warm it is fine. Having tested the SAD off the car - with 12v pluged in and seeing the hole dissapear as it should, I took it that it is working. I then went on to clean out all hoses, throttle body, purchase new ECU temperature sensor, checked oil filler neck for bolt etc etc!

 

So I may try replacing the SAD as it is the last thing that can be wrong (I think, hope!). Before I do so, if I connect a volt meter up to the plug, will it produce a read out immediately (with engine running) or after a short period (few minutes)?

 

Assuming the SAD is receving power, could the thermostat inside be broken - it is not detecting/reacting to a change in temperature? I am slightly at odds as to how it opperates with electricity and heat. When we say heat, do we mean that generated by the electricity supply to the SAD or that conducted as a result of being stationed next to the thermostat housing?

 

Sorry, lots of silly questions I know but someone has got to ask them!

 

Thanks again.

[skanny 0]

Hi,

 

I am interested to know when the power reaches the SAD plug, is it as soon as the car is started?

 

I have the idle problem whereby you start the car and it barely ticks over, then once warm it is fine. Having tested the SAD off the car - with 12v pluged in and seeing the hole dissapear as it should, I took it that it is working. I then went on to clean out all hoses, throttle body, purchase new ECU temperature sensor, checked oil filler neck for bolt etc etc!

 

So I may try replacing the SAD as it is the last thing that can be wrong (I think, hope!). Before I do so, if I connect a volt meter up to the plug, will it produce a read out immediately (with engine running) or after a short period (few minutes)?

 

Assuming the SAD is receving power, could the thermostat inside be broken - it is not detecting/reacting to a change in temperature? I am slightly at odds as to how it opperates with electricity and heat. When we say heat, do we mean that generated by the electricity supply to the SAD or that conducted as a result of being stationed next to the thermostat housing?

 

Sorry, lots of silly questions I know but someone has got to ask them!

 

Thanks again.

 

I dont know how long it takes for the car to send the +12V to the SAD heating element but from what i have read there is a heating element inside the unit which along with the conduction of heat from the engine coolant passing nearby will result in actuating the bimetallic spring (not thermostat)and closing off the hole inside the unit.

if you have tested the unit off the car and it closed over then there is nothing wrong with the bi metallic spring.