Surging Idle and Coolant?
 

Ok, in continuation with the other threads I have on the rebuild I did for my brothers EP3 (K20A3). We now have it started, broken in, and currently no CEL's. There is a consistent surging idle once it does get somewhat warmed up between 1K and 2K that is pretty rapid. Now it has led me to believe it is air in the cooling system. Everytime we jack it up and pull the cap off, the coolant slowly will drop in the radiator fill neck, as if the air pockets are coming out. That is with the engine off too! What bothers me, is I am almost through my 2nd gallon, and according to alldata, the overhaul coolant capacity should be 1.4 gallons. I cant see any leaks present. And there does not appear to be a bunch of white smoke as if the car is burning coolant somehow. There is some white smoke when we start it, but that just appears to be the exhaust from being somewhat cold outside now.

Any ideas where it could be going? Going outside now to see if maybe the heater core could be leaking into the interior?

Re: Surging Idle and Coolant?
 

So after running it jacked up in the air for a few minutes, the CEL came on for the PCV system malfuntion and idle system malfunction/IACV malfunction. Not sure if that could be because of the varying idle if in fact the coolant is to blame.

Re: Surging Idle and Coolant?
 

Another update. I tried driving for a few minutes. Coolant level is still dropping, but not burning or leaking. Then I tried the idle relearn procedure after I got the car warmed up. Reset the ECU, let it idle for 10 minutes (and by idling I mean the surging up and down), and then shutting it off for 20 seconds, then letting it idle for 5 more minutes. After about 1 minute of the 5 minutes for the second idle, it pegged it self at 2K rpms, almost like it was hitting a rev limiter, but it allowed me to go past it, and as soon as I let off, it drops down to 2K rpms again and sounds like it is hitting a rev limiter.

CEL came back on when it did that for the same IACV and PCV deal.

Please any help would be great!

Re: Surging Idle and Coolant?
 

I haven't kept up with your other threads, so I apologize if you've already mentioned this. Did you try cleaning the IACV? Is the PCV functioning correctly? Sounds like you might have a vacuum leak too.

Re: Surging Idle and Coolant?
 

Ever find the problem? I have the same issue with an ep3 I just did.

Re: Surging Idle and Coolant?
 

could be and air pocket! IF theres no/little coolant getting through the coolant lines to the IACV it will surge like that. That being said make sure you reconnected the coolant lines in the proper order.

When bleeding the system make sure you turn the heaters on full blast,jack up the front end, also using a spill free funnel will help LOTS!

Luck