High Idle after installing new turbo

[NickSJ]

Last night I installed a TE44 and Poston 3" 2pc downpipe (ported stock elbow), with a new oil line, drainback gasket, and composite 3-bolt turbo-to-header gasket.

I fired it up, and the idle in park/neutral was 2400 rpm, in reverse/drive was about 1200 rpm. Waited for about 20-30 seconds to see if it would drop down to normal, then shut it off. The only obvious leak (smoke) was maybe not a leak at all - just at the downpipe joint near the elbow, where I had put some ultra copper sealant.

I'm running a Thrasher, which normally idles at 650 rpm in drive. Also running an LS1 MAF and Translator. Also have a ScanMaster. I checked around underhood, I didn't see any obvious things (like vacuum lines unhooked, etc.)

The only thing I can think of is that I cracked the vacuum elbow which connects to actuator / turbo. Would a vacuum leak at this point, cause this?

Any ideas? Thanks,

Befuddled,
:fragez:

[jmidolo]

Things to check, see if you cracked the Y hose, most likely that's the case since they get brittle with age. #2 check to see that you didn't leave any gap or fold in the hose that attaches the MAF pipe to the inlet bell of the turbo. Make sure there's no leaks there or if you took off the uppipe too, check there. I'm betting it's the Y hose.

[Eric Marshall]

Did you have the battery disconnected? The IAC may need to reset itself. Usually just turning the car off and restarting it will fix it.

[NickSJ]

Thanks for the tips.

Battery was never disconnected, but I'll check IAC connector in case it came unplugged when I removed up pipe.

Did shut off and restart once, for another 20 seconds or so.

[HairDrier]

Did you remember to put the vacuum line back on the actuator?

Sometimes the vacuum tips off the solenoid bust off, maybe one is cracked?

[NickSJ]

Got it. Found the IAC connector unplugged, must have knocked it when removing up pipe. Car runs great now, that TE44 sure can melt those Nittos.

Thanks for the help.