What is the expected vacuum reading at idle?

[rb6freak]

Originally Posted by qtwre

Interesting that you mention fuel trims because I find my idle is always reading in the -20s. That means it's pulling fuel, right? While a vacuum leak would be causing it to add fuel? Is -20 a lot?

Here is a short Ecutek log in case you or anyone else is interested in taking a look. My issue is that once the car is warm, when I disengage the clutch (press the pedal) while in motion, it keeps the RPMs at around 2k (sometimes it bounces instead.) Sometimes it even propels me in gear with no throttle at 2k rather than slowing to idle. This persists until I put the transmission in neutral and re-engage the clutch. It will then idle nicely so long as it's spinning the input shaft.

So this log is of me moving slowly in a parking lot, then the clutch pedal is pressed and I'm rolling for a few seconds, then stopping.

I'm going to have my mechanic check for a vacuum leak tomorrow because I can't find one by eye and poking around.

This is with a stock fuelling system and AVO turbo.

I briefly reviewed your log. Now I'm no expert so take my findings with a grain of salt. You're log doesn't appear to be a vacuum leak. You're fuel trims would be in the positives at idle, much higher than what you see. I suspect its your tune.

What I suggest is you talk with your tuner if you find no mechanical problems. If this is a base map, I suggest you drive straight to a tuner or find someone who will remotely tune (etune).

[xwd]

-19 to -20inHG is what I read taken right off the brake booster line on an AEM failsafe.

[King Tut]

Originally Posted by Sportsguy83

PSI is not equal to inHg which is what most gauges read.

Idle should be -18 to -21 inHg.

This. I believe the issue is the OP's tune.

[woode]

Interesting.

When I first turbo'd my car I was seeing -21 to -22, now I see -18 to -19 generally. When it's really hot and I have been driving for a while it might pull -20.

I have been attributing it to starting to wear down the piston rings, although it seems it is still doing alright maybe compared to others.

[qtwre]

I had a vacuum leak test done yesterday by my mechanic. He pressurized the intake tract with smoke. There was a tiny leak at a fitting on my catch can but it didn't change my bigger problem.

I'm working with my tuner to diagnose it remotely. Hey, at least we all know what a good vacuum reading is supposed to be now. Searching didn't come up with anything so this will help people of the future.

[Kris86]

Originally Posted by qtwre

I had a vacuum leak test done yesterday by my mechanic. He pressurized the intake tract with smoke. There was a tiny leak at a fitting on my catch can but it didn't change my bigger problem.

I'm working with my tuner to diagnose it remotely. Hey, at least we all know what a good vacuum reading is supposed to be now. Searching didn't come up with anything so this will help people of the future.

What ended up causing the vacuum leak?

[guybo]

Is there a Torque Pro PID for vacuum?