raised vacuum reading?

[otofmyway6]

Hey everyone
so heres hte story...i used to boost fine and idle at 18inHg and decelerate at about 22inHg...now i idle at 16 and decelerate at 20...what could have caused this? it just changed one random day. Thanks
Andy

 

[RossY]

I would probably say that you have a boost leak somewhere. If you want to fix it then build a leak down tester to find the leak. Directions can be found at http://www.vfaq.com/mods/ICtester.html.

 

[IHeartTurbo]

Just to clarify, that's not a leak down tester, that's a boost leak tester. A leak down tester applies compressed air directly into the cylinders to find the culprit causing lower compression numbers (i.e. piston rings, intake valves, exhaust valves, head gasket).

 

[Defiant]

Check you cam belt timing.

It's not an intake leak, because vacuum is only between the valve seats and the back side of the throttle plate.

Also check the line going to the gauge. Look for a kink.

 

[Matts95TSiAWD]

wow mine sits at 15in

has since i bought it, is that super bad?

 

[RossY]

Just to clarify, that's not a leak down tester, that's a boost leak tester. A leak down tester applies compressed air directly into the cylinders to find the culprit causing lower compression numbers (i.e. piston rings, intake valves, exhaust valves, head gasket).

bah..details details, the link clarified it for him

 

[JiveMasterT]

wow mine sits at 15in

has since i bought it, is that super bad?

some days mine sits at 15in and sometimes at 20. it depends on the weather and if the car is warmed up or not.