Installed boost gauge, low vaccuum.

[pgt892]

Ok well I got the vaccuum hose in today that I needed so I installed my boost gauge. I follwed the instructions to the T and when I started up the car and took it for a spin the lowest vaccuum reading was 12 in. Hg. It was boosting properly at 7psi but I am worried about the low vaccuum reading. I searched on this topic and found the normal range to be around 18-20 in. Hg. Running a vaccuum this low I would imagine that I have a leak somewhere but I checked the FPR line, the BOV line and the unused carbon canister line and all were on tight or capped off. Could anyone point me in the direction of where to look for the problem. Thanks, Alex.

[Luke]

Are you saying that the vacuum only reads 12 whether you're driving or at idle? It should sit at 17-18 at idle and mine normally hits 20-21 when i let go of the throttle while driving.

When I installed my boost gauge, i had kinked the nylon tube when i put it in the gauge pod. That was messing up my vacuum mostly and sometimes it didn't show full boost. I would double check the vacuum line all the way back.

[ItzGenX]

I've found that different boost reading devices read different amounts. When I had my Blitz SBC ID-III installed, it read anywhere from 18-23 in vacuum. I then took out my Blitz boost controller and installed a Greddy Profec E-01. It now reads 8-12 in vacuum without anything else changed except the two devices.

[Cyberkreig]

My e-01 also reads low vac. Always has, but the car runs and idles fine so *shrug*.

[nismostate]

that's weird. that just tells me that boost gauges are BS. does that mean 10 psi might be more or less?

[UsedToOwn240SX]

Hey Alex,

I'm the guy who has s13 w/ redtop in Westfield. I have a compression tester if you want to check your compression. I also have a home made boost leak tester. Give me a call if you still have my number of drop me an email at [email protected].

UsedToOwn240SX

[chickentendah]

The most UNobvious cause to low idle can be your timing. For the longest time last summer, I had an unstable idle, low vacuum @ idle (around 12-15 In. Hg), and lack of power. I double checked all my piping and vacuum hosing. They were fine. I then guessed that it was a pinhole leak somewhere. After putting on my FMIC kit, I found out I was wrong. The problems were still there.

Later, I found out that it was the TIMING the whole frigging time!

[pgt892]

How did you set the timing correctly. I was just going to use the Phase 2 CAS way of doing it. http://www.store.yahoo.com/pha....html

[chickentendah]

I had a friend do it for me. He told me that he went exactly by the Nissan Factory Service Manual procedure.

[Phax]

A vacuum leak can occur anywhere in the piping. When I noticed that my vacuum crept down from -22 to -18, I eventually chased the leak down to the piping going into the SMIC.