[Davo86]

Hi guys

Today I tried to delete my pcv valve and reroute the blow by through a catch can and back to the sump. When I started the car it idled really high. I assume that the ecu is tuned to have the extra gasses coming into the intake and that is why it ran rough? Is there a way to get around the pcv valve? I have a turbo manifold and Haltech ecu going in soon and I would rather the pcv outlet didn't vent into the intake manifold.

Thanks

[tanshi]

I doubt it would be venting enoughto make a difference.

even if it does, when you run a new ecu you should be able to tune out that difference

[fordem]

My first question is do you understand how the PCV system works?

Assuming you have MPI there will be two hoses connecting the cam cover to the intake, the first before the throttle body and after the air flow meter, and the second after the throttle body and the PCV valve will be in the second hose - the first hose forces all air flow through the PCV system to be metered by the air flow meter.

When you "deleted" the PCV valve, how did you "re-route the blow by through the catch can and back to the sump"? There are four connections - two hoses, two ends each - which did you disconnect, which did you connect to what, which did you plug?

The PCV valve controls air flow from the cam cover into the intake based on intake vacuum - high intake vacuum (engine at idle) results in low flow through the valve, low intake vacuum (engine under load) results in high flow through the valve - removal of the PCV valve without somehow restricting the airflow at idle will result in high idle speed because of the additional airflow.

[Davo86]

Yes it's Mpfi. I used a 12mm brass fitting to replace the valve and ran it to a catch can and then ran the oil return line from the catch can back to the block. I am also running the other line from the valve cover through a second catch can in the same manner. I was experiencing a lot of blow by with oil pushing out from the valve cover gasket. I think I will replace the pcv for now and wait until i install the new ecu until I delete it.

Thanks

[Davo86]

I plugged the intake manifold pcv inlet and I didn't need to plug the one on the pipe side of the throttle body as it had a dodgy install into a silicone tube. I just replaced the tube. The engine is a baleno g16 b and it had all been done pretty roughly.

[fordem]

I still have no clue how the plumbing was altered ...

With EFI engines, high idle speed is usually the result of a vacuum leak allowing air flow into the intake, bypassing the throttle plate and/or idle air control system - the ECU is going to see this in two places, the O2 sensor, which will cause it to add fuel to compensate for the lean mixture, which is what prevents the engine from stalling out and allows the rpms to increase, and the ECU will see that RPM increase and try to reduce it using the idle air controls.

Quote:

I used a 12mm brass fitting to replace the valve and ran it to a catch can and then ran the oil return line from the catch can back to the block.

I believe the PCV valve sits in the cam cover (most do), so it would appear that you removed it, ran a hose to a catch can and then "back to the block" - except it never went to the block originally, so how can you run it back to the block? Or do you mean back to the cam cover? If it was back to the cam cover, how does it vent the excess blowby.

Quote:

I plugged the intake manifold pcv inlet

This is where the air would get in, so if it's plugged why would the idle increase?

Quote:

I am also running the other line from the valve cover through a second catch can in the same manner

Presumably this is the line that connects to the intake between the air flow meter and the throttle body - so this now runs to a catch can and back to the block? Did you add to connections to the block somewhere?