So i just installed a megan underdrive pulley and now my idle is slightly jumpy

it happens consistently and sometimes dips below 500 rpms even with no components running. The only thing i can think of is that since the idle control valve is run by voltage received from the ecu, is the underdrive pulley not getting the valve enough voltage to function correctly?

edit: could this also be the timing? as i changed the timing belt and water pump at the same time, so if my timing is off like 2 degrees could that be causing a weird idle?

 

After the belt/pump swap, did you check to be sure your motor was mechanically timed correctly? Then, after warming up the car andsetting idle, did you set the ingnition timing with a light?

 

I did not do so, it didn't even cross my mind... so even though the engine could be timed correctly if the ignition is slightly off the spark's not arriving at the correct time?

 

Budd, I got the same problem. I didnt even change the pulley, I put a CAI in and I think thats part of the problem. The car isnt programmed to notice these types of upgrades and takes time to break in. I changed my gas to Ultimate and it seemed to stop. Then I changed to Premium and it was doing it again. So try changing to the best gasoline and see what happens. To be honest I thought my car was riding a lot smoother, so give that a try also

 

^Aren't you supposed to be running Premium in your Si?

at any rate, changing fuels isn't going to help.


bp4131017 - You've got to make sure that you lined everything up correctly when you put the new belt and pump in. Then from there set your idle, then set your ignition timing. If you've still got the idle issues, try bleeding/filling the coolant.

 

Yes, im pretty sure. But it doesnt seem to be running as well with the premium than with regular. The gas miledge seems to be terrible for some reason, maybe its just in my head. But i used ultimate and it was running great I had no problems.