Have an 05 EVO VIII that came with Injen intercooler piping with the stock old dirty EVO intercooler. Last night I installed a new larger intercooler on it and kept that same Injen piping. It used to run perfect but now the second I turn the car on it revs to 5,000RPMs on it's own and won't stop! I assume its a boost leak somewhere but I had one before on the left elbow hose coming out of the intercooler and into the piping next to the ACD pump but last time the car didn't over rev on its own. It would just sputter and rev limit itself around 2,500RPMs just before the turbo would spool and I basically needed to run turbo-less until I fixed it. Now its over revving? I don't get it.

Possibilities:

Vacuum/boost leak?
IACV sensor loose or dirty?
TP sensor loose or dirty?
Air leak in throttle body gasket?
I did have a good tune before but now I need another one?
(^Those are possibilities I just researched online^)

Someone please help! I'm out a car!

 

How long have you let it rev for until you turned it off?
Was the battery disconnected while you were swapping out the intercooler?

((BTW you posted this thread three times.))

 

Battery was not disconnected. I didn't need to remove anything but the hood latch assembly. Started up fine, did a quick 1st gear pull in the parking lot (nothing crazy), and then it started revving really high on its own, I got scared lol, and I shut it off. I turned it on and off 3 times after that same thing kept happening but immediately this time.

 

Did you work around the throttle body? Maybe a cable tuck? Check to make sure the tb is opening/closing with out resistance. Then boost leak and check maf/wires.

 

If u did Tune before u swapped out the Ic ur gonna need anther tune

 

^^ +1

I would start looking at the throttle area first. Retrace all the areas you were working around and see if anything obvious looks wrong. I usually start to jump to more complicated conclusions when it almost always ends up being something simple. Interested to see what you find out.

 

happend to me when i installed just a stupid short ram intake. i did what you did and same thing happend to me i thought i had a POS of a car i was mad. I disconnected the negative and that unplugged the electronic connectors to the TB and connected again. Went into the cab and put my foot on the break for about 5 minutes. Connected the cable again and it fired up right. could be the problem i do think u need a tune if u went from a small intercooler to a big one but if u just swapped same size i dont see it being much of an airflow problem just a little different and it confused the ecu but still tune is always a must if u change a clamp ( that was a joke about the clamp haha )

 

Pull off piping at TB and check the plate itself. Maybe coupler/clamp/something stuck there. Happened to me on 3000gt on a test drive even. Coupler stuck on the TB causes erratic idle and boost.