Vacuum leak driving my insane
Vacuum leak driving my insane 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?
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?
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.
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.
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.
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.
