SAD issues

[Richie-Van-GTi 74 2 Cars]

How well does the SAD close off? Mine still passes a lot of air but the plate looks closed inside when hot. Literally can wind the throttle bypass full closed and throttle stop fully back and it idles at 1100. Pulled the pipe off the sad and there is a stack of air going through it.

[Tom Fenton 1,561]

It should shut so it passes next to nothing. Clamp the hose going to or from it and see what the idle speed does. When working properly and you clamp the hose, there should be no change in the engine speed (assuming fully warm). 

[Leslie green 124]

I noticed mine was the same  throttle screw fully closed and butterfly closed and still 1100 rpm , will need to check once I get mot over. 

[Thijs_Rallye 89 4 Cars]

If there is no change to the idle RPM after clamping the hose as Tom suggested, check for air leaks at injectors / seal surface of intake manifold and most importantly all oil breather and fillers hoses.

[Richie-Van-GTi 74 2 Cars]

On 4/4/2025 at 8:49 AM, Tom Fenton said:

It should shut so it passes next to nothing. Clamp the hose going to or from it and see what the idle speed does. When working properly and you clamp the hose, there should be no change in the engine speed (assuming fully warm). 

Half hour of heater on and heated the housing to scalding and I can still blow through it easily, no split pipes etc. it is reduced from fully open but certainly not a struggle by any means. Tried adjusting it both ways and no difference, knackered???

6 hours ago, Thijs_Rallye said:

If there is no change to the idle RPM after clamping the hose as Tom suggested, check for air leaks at injectors / seal surface of intake manifold and most importantly all oil breather and fillers hoses.

No difference when blocking hoses either but can't find any splits etc, seems like the oil breather just passes through the cap and gauze to the elbow on the other side if the throttle body though, normal??

[Thijs_Rallye 89 4 Cars]

There is a breather hose that runs from the top of the valve cover to the T at the bottom of the oil filler hose, oil filler hose should also be free of splits and are often hard to see without removing them imo. Then there is a breather hose that runs from the bottom of the engine block to the side of the oil filler "pot" or however it is called. Another item often overlooked is the bolt that bolts the oil filler pot to the intake manifold. A pin hole is enough to throw off your idle so look closely.