[Ginger_Extract]

Hey All, been trying to track down an errant boost leak, and I was hoping y'all could help me, since I'm having a bit of a brain fart.

I've been using this helpful N54T thread about 30FF and finding boost leaks: http://www.n54tech.com/forums/showthread.php?t=13114

Background: N54, 6MT cat. The car has been slow to come onto boost, i.e. can barely make 10psi by 4500rpm, even on E40 blend/Map5 JB4 and was constantly under-target in the logs and generally felt like a dog.

Tested the diverter valves, found that they were leaking above 10psi in one and ~15 in the other, okay. I replaced with a new CP and Tial BOV.

The car feels better, comes on to boost a bit smoother and is able to make more peak boost, but is still under target except for a brief window from ~6000-7000rpm, ha. Interesting, on initially tip in, the car is always right on target for boost, but about half a second into the pull, the car gets heavy throttle closures and goes back to being way under target boost.

Here is where I need your help, and where I am at present.
Tonight, I resumed vacuum testing components on the car, but my brain is a bit frazzled and I can't process the information I found.

In the N54T thread, they say the following:

"Vacuum to Wastegate solenoids
Follow hose from the top a canister to a solenoid. Remove hose at the solenoid and connect vacuum gauge. Start car, gauge should read about 26” Hg at idle. Don’t know acceptable limits but if it’s much lower than 26” trace ALL hoses all the way back to vacuum pump (behind oil filter). Replace leaking or pinched hose.
Reconnect the hose and repeat the vacuum test on remaining solenoid. "

Preface: I'm using a space piece of tubing to do all of my testing below. This line is tested leak free.

- Okay, so I do this, and both boost solenoids are only drawing ~15-16" vacuum. The rear solenoid's numbers are erratic and kind of bounce around while the front one stays at 16" when the car is on.

Again, using the same piece of test tubing, I hooked my vacuum gauge up to the vacuum canisters, i.e. the last source of vacuum before the boost solenoids, and they both have no problem putting out 27" of vacuum.

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Does this mean that both of the boost solenoids are out of whack/dying, or am I doing this wrong?
My next course of action is to put a vacuum pump (the trusty MityVac) on the "in" nipple of the solenoid and the vacuum gauge on the "out" nipple and test leak down. Alternatively, can I jam the voltmeter into solenoid and test voltage? If so, please advise on figures I should be seeing.

I'm all for second thoughts and opinions. My brain isn't processing this information, so I'm getting a bit flustered. Thanks!

[Sgop335]

Each solenoid is measured separately by removing thr bridge between them and connecting gage to the tee while plugging the other tee.

At idle around 14-17 in vacuum. Important thing what they measure on throttle. This can only be done with a helper looking at the gage while driving.

Full throttle esp. 3rd gear and up, solenoids go to 21in stay ther for a little and drop to about 10 or more. If they dont shhot to 21 on wot it is not functioning properly.

[muncie21]

you're on the right track. Figure out if it's the vacuum line or the actual boost solenoids now.