BOV leaking... Affecting boost gauge reading.
 

I've finally gotten around to installing my electric Prosport boost gauge. I've not ever had a boost gauge before this one. (So, I kind of don't know what to expect.) - It is an older gauge, so there isn't any sort of elevation adjustment. I don't think that is the issue, though.

At idle the gauge is seeing 20 inHg. When I rev the engine, the gauge sees 5 inHg at most. Even at 6-7k RPMs. No boost. I've not yet driven with the gauge. I was just wanting to see how it functioned...

I found out the BOV is leaking. (Surprise!) - Anyway, I feel that it may have something to do with the car not building boost. I'm most likely going to remove the BOV tomorrow and see how the gauge functions then.

Anyone have any input?

Well, you won't get any boost in neutral anyways, the engine needs some resistance to make enough exhaust to give you boost. Same on all my three turbo cars.

As for my readings, I don't have InHG, but I have another kind of reading which I THINK is divided by ten to your, and I have -0.6 to -0.8 vacuum, with the gauge going to -1.0. My boost goes to 0,7 bar (it should), but without working boost solenoid I get 0.4-0.5 bar. Without the wastegate actuator hose I get 0.9-1.2 bar. 1 bar is 14.4 psi I think.

It's possible the BOV leaking would cause a hard time building boost. Not likely, but possible. I have a knockoff Greddy Type RS that I know leaks at idle (standalone don't care :) ) but it seals just fine under boost. In fact, most BOV's that I know of seal better under boost than at idle. The type RS valve has springs inside that you can adjust. It's difficult to get it just right, but eventually you can get it to a point to where it'll blow off as necessary, but won't leak at idle. It's a sweet spot that's hard to get, but it's achievable.

By the way... if your boost gauge is hooked up to manifold vacuum/pressure, then the BOV has jack to do with the boost gauge reading. There's a throttle plate in the way.

Ah, alright. That's kind of the answer I was looking for. I wasn't sure if that was the case or not.

Yeah, I've got a knock-off BOV that I received in a bulk trade. It is adjustable, so perhaps I'll mess with that a bit.

I have the boost sender, for the boost gauge, on it's own nipple I've tapped on the ACV block-off plate. The BOV and pressure sensor are on the same nipple.


Thanks for the replies. I'll mess with this a bit today/tonight.