01fxst

Heya guys. The 383 is finally together and we fired it up today for the first time. She fired up and seems to be running well except the idle is high. She should idle at 875, but is idling around 1500 - 1600 RPM. The map sensor reading with the engine off is .99 and with the engine running is between .3 and .35. We assumed a vaccum leak, but all the hoses are new, we've checked and rechecked them (and again). We've sprayed brake cleaner around the intake with no change. What else could cause a high idle like this?

Details:
95 Z28 M6
Golen street/strip 383 shortblock
Ported stock heads and intake (stock valves)
Stock throttle body (until I can get an ASM unit)
42 lb injectors
stock fuel pressure regulator
Comp Cams XFI cam
Long tube headers
emissions deleted
K&N FIPK
Stock MAF
PCMforless tune

Other than the idle she is running well, no leaks, no smoke, fires right up. What else am I missing?

.Rick

ss.slp.ls1

iTrader: (36)

You could try and remove and clean/replace your IAC valve.
Did you check the intake elbow for tears?

Green3spd

iTrader: (7)

^^^vacuums?

01fxst

I'll check that this afternoon. Elbow should not be a problem since I have a trickflow, but I should check the rubber boots that connect the elbow to the MAF and the throttle body.

hitmanws6

iTrader: (20)

how long was it sitting? my 353 did exactly what yours was doing. turns out there was some rust built up in the coil in the TB. It was causing it to stay open a little at idle. It went away after 2-3 days

Green3spd

iTrader: (7)

figure it out..?

01fxst

We didn't get a chance to work on it yesterday. The throttle blades are closing all the way. We need to check the IAC. Also we're going to keep looking for vacuum leaks. Maybe the throttle body gasket, or the block off plates on the back of the intake.

I changed out the IAC last summer to try and resolving a stalling issue. That didn't fix the problem, so I kept the original IAC. We'll probably try putting it back in. Turns out the stalling last summer was the oil warming up, thinning out and since the bearings were trashed the friction would bog down the motor and stall it out. We fixed that problem by calling Golen. On a side note, Chad is an awsome guy to work with. I HIGHLY recommend Golen for anyone who needs their services.

01fxst

Got it figured out. It was a bad IAC. Took the throttle body off and plugged in the IAC. Turned on the ignition and the pin on one moved, on the other did not. Put the working one in and fired it up and she rumbles. Now we just need to get her broken in, then off to get dyno tuned. Thanks for the help guys.