Very quick question about possible boost leak?

[giovanniv]

Ok so I am kinda worried about he vac when the car is like at idle. It stays around 23-26ish 90% of the time. Is it just because I have a boost leak? Is it bad to have more vac then normal which is around 20ish? Thanks

 

[habitatguy187]

A boost leak will actually lower vac reading if anything. I've never heard of anyone's vac being that high at idle, highest I've heard of is 20, with 18 being the norm. What's your boost gauge read with the car off? I would check it first, because I can't think of anything that would cause this mechanically with the engine.

 

[giovanniv]

It reads right below 0 but it's just a hair below it. I'm not sure either why it is doing that. So I'm not losing any boost obviously since its below what its supposed to be at right?

 

[habitatguy187]

So I'm not losing any boost obviously since its below what its supposed to be at right?

No not necessarily, it just means that the boost leak isn't past the throttle plate. A wiseman once explained it to me like this:

"Before the TB it's a boost leak, after the throttle body it's a boost leak and a vacuum leak."

 

[steve]

It stays around 23-26ish 90% of the time.

I suspect your gauge is off.

 

[zhjiln]

23-26 in HG is really wierd numbers for idle ..

the average is about 17-21 in HG ... what brand is your boost gauge ? and is it hooked up from you FPR solenoid or the intake manifold nipple ?

 

[nightracer91]

If it is below 0 with the car off, then it is going to be that far below all the time. Example. If it is 4 inHg below 0 it will read 4 inHg lower when at idle (24 inHg instead of 20 inHg) and 2 psi lower under boost (14 psi instead of 16 psi) I suspect your gauge is off.

 

[giovanniv]

It probably is just off a little then cause it sits like right under 0.

 

[HaZ]

thats odd my vac always reads 10 on idle I thought that was the norm

 

[habitatguy187]

thats odd my vac always reads 10 on idle I thought that was the norm

, you have vacuum leaks, it should read -18.

OP, you need to swap out that gauge with another one and see what's up, trusting that gauge is like trusting the stock one, a big no no

 

[steve]

thats odd my vac always reads 10 on idle I thought that was the norm

Although being at 5000 ft has an impact on your normal vacuum I think 10 in hg is still too low. Do you have cams in your car? That can also lower the normal idle vacuum depending on how they are adjusted. So can badly timed stock cams.