my new rebuild engine idles at 4k rpms (throttle cable not even attached so its not that)

what on earth is causing this?

what can i adjust? powerfc? throttle position sensor? timing?

 

what the hell vacumm leak? did you check the throttle plate, sounds like maybe its stuck open a bit.

 

I don't know where the vacuum leak would come from. everything looks how it should be, nothing is missing to my knowledge.

myself I'm outta ideas of how or where to look to solve this

 

It's gotta be some sort of massive vacuum leak. Is it possible for the IAC valve to get stuck open?

You haven't messed with the PFC since the last motor was running, I assume?

 

I suppose its possible. Try plugging up the IAC and see what happens.

 

IAC valve = ?

I don't understand acronyms

 

if I let the engine run the RPMs creep past 5,000 without the throttle body even being open

and no i have not touched the ecu since last time it ran. the ecu sat in the car for 19 months while i have been fixing the motor

 

Idle air control. It's mounted on the upper intake manifold and has a coolant line running to the throttle body.

Also, now that I think about it, if you still have the AWS (accelerated warmup system), try disconnecting it. It should be on the underside of the UIM. I'm guessing it's been removed, though, since you have a Greddy TB elbow if I remember right.

 

this is what i have

 

when i uplug the TPS this is what the pfc reads

 

I deleted the iac and the secondary throttle plates, so that isn't the issue. Did you put the correct injectors in the primary rail, should be the 750 iirc

 

thanks, yeah I had the injectors serviced and put the correct injectors in the correct place

 

If we are certain that the throttle plates aren't the issue, and the IAC has been deleted, I think we can conclude some things.

First of all, this system is MAP based rather than MAF correct? Setup like a FD?

Considering this, there must be a vacuum leak somewhere past the the throttle plates. Can you snap pictures of the rest of the intake?

 

Another thought. Can you pressurize the intake? That would show a leak real quick.

 

Yes it is map based, basically fd electronics and power fc on a S5 T2

 

thanks guys

i will snap pics later tonight of the intake, not sure how I would pressurise the intake, any suggestions ?

 

the only way I could think of of would be to use some sort of a rubber cap on the intercooler piping near the throttle body. Then send compressed air in through a vacuum port.

 

You'd have to block off the engine side of the manifold, too.

 

while it's running shoot all the gasket areas with brake cleaner if the idle goes down some you've found where the vacuum leak is.

 

Do you have the square gaskets on the injectors? It looks like a double o-ring. They go on the engine end of the injectors, around the pintle caps.

 

not sure what a square gasket is or if I have it or not, does this picture show it?
I know i installed the injectors with the little baffle piece that drops into the center iron which helps atomise the fuel/air. I know the injectors had new o ring type seals replaced when i had them serviced.

 

Sure you don't have something stuck in the throttle body like a zip tie? Otherwise are you sure you have all lines post throttle body connected properly? Should the lines be rubber, they are not cracked or broken? Finally, are you sure you have your map sensor connected properly?

Best of luck!