TchargedLS1TA

iTrader: (9)

Im trying to figure out where this vacuum leak is using some carb cleaner, but cant pinpoint where it is, if I even have one. The car has a 234 cam in it on a 115lsa with PRC stg 1 heads. Its pulling anywhere between 8-12 inches of vacuum while its surging and the needle is also going apeshit.
Like I said it surges pretty bad and has a hanging idle when driving.
I dont know what else to look for. Is there an easier way to check for a vacuum leak?

eallanboggs

iTrader: (1)

smoke machine

chpmnsws6

iTrader: (70)

Is the cam Dot to Dot? that will cause needle fluctuations more then a vacuum leak. Do a leakdown test to make sureall the intake/exhaust are sealing. An intake valve thats not opening/closing like the rest will also cause a fluctuation.

ssheets

iTrader: (1)

I had a similar problem. Turns out I forgot to torque the throttle body down. My idle was hanging pver 3k rpm at times. I kept looking for vacuum leaks and dumped an entire can of starting fluid and carb cleaner all around the manifold and vacuumm lines. I didn't spray right on the TB cuase I figures it would just enter into the intake side. Well when I went to check all of the manifold bolts and then the TB I about chit when the three throttle body bolts were still only hand tight. Now the throttle body I just missed when I was assembing, but I was surprised when I checked the intake manifold bolts that I could get another turn on them after I had torqued them to spec on assembly. I likely overtightened them now since I was paranoid about vacuum leaks and trying to chase my tail for a week.

You can also plug off the PCV and Evap lines with vacuum plugs to eliminate them as leaks.

5.3LJimmy

iTrader: (10)

If your idle is surging the needle will fluctuate. Try unplugging the IAC valve to stop the surging then do a vacuum test. It sounds to me like you need to get a better tune for that cam.