Guys, I'm about had it with this engine. Here's the back story.
I have a 2001 Legacy B4 with a single turbo (vf28) swap and Apexi FC commander ECU.
I recently blew the motor (EJ208), and found a replacement (EJ206) from an auto B4. It saw it run for a few minutes from the junked car it came from, so as far as I know it was a good motor when it was pulled.
I pulled the parts off the busted motor, and put them on the new motor to include the oil cooler, oil lines, turbo, fuel lines, injectors, inlet and wiring harness. I did not use the manifold because it was dirty and had shrapnel in it.
I installed a new pressure plate, friction disc, bearings and had the flywheel resurfaced.
I put in new NGK spark plugs, used the coil to spark plug packs from the new engine.
The timing belt was inspected and the water pump was swapped from the bad motor, along withe some of the timing belt pulleys that were better than the junk yard motor. The timing was set by a trusted Subaru enthusiast.
I've also installed two catch cans, one between the crank vent and the inlet, and the other between the two rocker vents and the inlet.
After all of this, the car idles terribly. It may have a miss as well. It runs great under boost, and all things appear normal under load. Even the A/F meter shows rich under boost, but at idle it is off the charts lean. There are also random pops once the motor warms up at idle. A buddy said it may be a backfire. It's not loud, just a dull thud here and there.
Also, the O2 sensor (three wire) is not working. I've tried the original from the bust motor, a friends "working" sensor and one from a Nissan. The last one actually has voltage according to the FC commander, but it stays around 0.06-0.18, and as the car warms up the voltage slowly drops. Under load the voltage looks more normal going back and forth between 0.1 and ~0.7.
I'm also going through gas like it's going out of style, like less than 100 kilometers per tank!
Tonight I cleaned up the MAF, but that did not change anything. I checked the spark plugs and replaced the coil packs from the busted engine. The plugs all looked the same, black around the top of the threads, white ceramic and not wet or otherwise dirty.
I'm running out of ideas here. I have a new O2 sensor on the way in the mail.
Does anyone think that a working O2 sensor will solve the rough idle, or is there more going on that I need to address? Why would the A/F meter (calibrated) show lean at idle when I can smell the extra fuel in the exhaust and have terrible gas mileage?
Last edited by sub4ru; 11-03-2012 at 10:22 AM..