Hi,
I am building a K20a2 (Euro Ep3 Type R) with a Rotrex Supercharger.

The SC setup was on a car, I removed it about 6 months ago and have just installed it onto a new car. On the old car it had a top mount intercooler. I have now fitted a FMIC.

The Setup is in this order: Air filter - Throttle Body - Super Charger - Intercooler - Inlet Manifold

The problem
When I start the car its idle fluctuates between 2000RPM and 1000RPM. If I remove the vacuum pipe from the map sensor then it will idle stably at 1000RPM but a little rough. (the map sensor is a 2.5Bar sensor)

I have tried altering the throttle response on the Hondata from one extreme to the other but it did not cure the problem.

I have checked all over for a vacuum leak but cant find one and guess because i can make the idle stable by removing the map sensor this isnt the problem.

Anyway hope someone can come up with an idea.

Thanks a lot

 

Have your IACV plugged in? with coolant lines to it? is it clean, or gunked up?