throttle bodies pressure

andygtir

Member
does anyone know what the pressure behind the throttle bodies should be at idle?

i assume you check it by attaching a pressure guage to the pipes above each butterfly valve, would a mechanical boost guage do the trick?

does this have to be done only when hot? as my idle is very lumpy at the mo when warmed up (rises and drops constantly between 1600 & 1200rpm) but its ok when cold so would be easier to check then.

any hep welcome :wink:
 
A

AJ4

Guest
Do you mean engine side of the throttle or inlet side ? There should be vacuum on the engine side and ambient or small vaccum on the inlet side.
 

ram5ay

Member
The pipes above each butterfly valve are for balancing the throttle bodies iirc, you would fit four identical gauges like for balancing carbs, and adjust the small screws so they all read the same. Think the general vacuum pressure isn't so important as this will vary depending on engine spec and condition etc.
 
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