68FBODY

The reason I ask is because my boost gauge is only reading 10psi vacuum. That seems low, is that normal (T into the fpr)? My boost sounds normal though, spike around 21 and by redline its at 16psi.

Skylineracer

iTrader: (21)

well mine is 20 for vacuum, odd that its 10

abdizzle

iTrader: (6)

Do you have Cam's? If not you have a leak.

BluEVOIX

iTrader: (69)

At vacuum with stock cams my IX is hovering right around 17-18. I am using VEI systems digital boost gauge. When they first came out back when I had an SRT-4 it was tested to be very accurate.

I have my boost/vacuum source T'd from the line connecting from the throttle body to the Diverter valve.

Either there is some sort of vacuum leak on the line, your boost gauge is melfunctioning and/or your boost gauge is not measuring vacuum in different Hg. I forgot the different readings if their in Hg in^2 or Hg cm^2 etc...

Also if you have cams it will lower your idle vacuum as well.

whoflungpoo

iTrader: (2)

yeah, I've got a built motor with comp 280 cams and still manage to pull 15 to 16 in/hg at 850 rpm

jyndrus90

iTrader: (3)

18-19 but my idle seems to be at 950 idk why

68FBODY

If i had a vacuum leak though wouldn't that effect the boost psi, since pressure would be escaping from the leak?

def1

iTrader: (6)

what elevation are you at? If your at high elevation your vacuum will be lower. Mine is right around 11 but I have cams. I think when it was stock it was at like 14

68FBODY

25ft above sea level, super low. so its deff. not that. I also don't think I have cams, although I did buy it used, but from the mitsu dealer

def1

iTrader: (6)

Get carb cleaner and run your car. have someone look at your vacuum gauge. Spray the carb cleaner over all the vacuum hoses. If the vacuum goes up then you have a leak. If the vacuum stays the same then you don't have a leak. You could also have damaged valves or other things causing low vacuum but I think you would have other problems with the car.

MitsuBeastly

need help... bought my car used... and its an 03... know it has idle issues allready being an 03... no vacuum leaks. forge bov, 9 turbo, full 3", no cat, injen intake w/ uicp and licp...
but everytime i have the a/c on, the car dies at lights... or vibrates harshly...
also, everytime i rev it and let off it drops down to ab 600 rpm's and goes back up
my JestR tune ended up being ab 10.2 to 1 afr's and it shouldve been leaner...
i live in Louisiana, center of the state, idk what the elevation is... i think ab 50-100ft above...
my idle vacuum at ab 950 is 18-19
being read with an HKS EVC 5

bump on this thread!!! info helps, dont wana pull my valve cover for nothing

lelek

iTrader: (4)

if the car runs with no issue i think it may be bad boost gauge

jl240

What was the issue I have the same problem ?? Wtf

escodotcarter

iTrader: (16)

^^^^ super old thread bump lol