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Old 07-19-2012, 01:11 PM   #1
SENZA PARI
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Member#: 300779
Join Date: Nov 2011
Location: Oshkosh, WI
Vehicle:
'09 Subaru Forester
Blackout

Default New engine installed - now 17-20 mpg :-(

Last month the oil pump in my '09 Forester (Premium, non-turbo) seized in the middle of a few hour long drive home... and of course the motor blew.
I replaced the motor with a newly built OEM motor. Everything is as it was stock, with the exception of the EGR port on the driver's side head being plugged.
Before the motor swap I was getting around 30 mpg in the summer, up to 36 if I hyper-miled it. It is lowered with the roof racks removed, intake, exhaust. The check engine light was usually always on due to the exhaust, however this has never effected mileage, other than improving it.

After the swap I had a fuel leak due to a bad injector O-ring, and at the time I was getting 18-20 mpg's, which seemed to make sense considering the amount of fuel being sprayed out (mind you I drove it like this for maybe only 15 miles before realizing I had a leaek).
I replaced the O-ring and the leak was fixed... however the car still gets 18-20 mpg's at best.

I took the car in to have the codes checked... the results were:

400 EGR FLOW
O2 SENSOR ONE BANK ONE

I personally did not look at the readout but this is what the technician told me.

I ordered a new upstream 02 sensor, however the plug does not clip into the factory engine plug, so I'm awaiting a new one. I've read that a bad O2 sensor can cause the ECU to dump fuel.... so it's possible.

The only other difference I can think of is the EGR being blocked off. The EGR port on the back of the head is plugged... this is how the new motor came. So I capped off the intake manifold as well.
I'm assuming this is where I'm getting the EGR flow code. The question is, would this cause the ECU to dump extra fuel? I've read that it can, and also that it shouldn't effect anything.... so I'm not sure.

As I've had the check-engine light on due to the exhaust for about 2.5 years now without any effect in mileage, I'm thinking the EGR is the problem...

Does anyone have any ideas? As is I don't even want to drive the car it's so bad:-/ Any help would be immensely appreciated.
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Last edited by SENZA PARI; 07-19-2012 at 02:25 PM.
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Old 07-19-2012, 02:16 PM   #2
RaceFaceXC
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How is the performance? If it's a dog in the low rpms but feels like it picks up in the top half or so of the rev range then I would bet an o2 fixes it.

Is the engine factory new? What model is it?
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Old 07-19-2012, 02:25 PM   #3
SENZA PARI
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Member#: 300779
Join Date: Nov 2011
Location: Oshkosh, WI
Vehicle:
'09 Subaru Forester
Blackout

Default

A quick update: After visually looking all around the motor I also found the following issues, which may be a factor.

Neither PCV line was connected back up at the valve covers:


IMAG0187 by SENZA PARI #1, on Flickr


IMAG0188 by SENZA PARI #1, on Flickr

This wasn't connected either:


IMAG0189 by SENZA PARI #1, on Flickr

And this guy was simply left hanging in the rear of the motor, connected to nothing other than the wiring harness plug:


IMAG0191 by SENZA PARI #1, on Flickr

This unit hooks up above the open fitting (shown above) and then turns 90 and into the stock airbox, which has been long gone. So, this gets hooked back up as it was, but what about the two vents on the valve covers?

Last edited by SENZA PARI; 07-19-2012 at 03:42 PM.
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Old 07-19-2012, 02:29 PM   #4
SENZA PARI
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Join Date: Nov 2011
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Quote:
Originally Posted by RaceFaceXC View Post
How is the performance? If it's a dog in the low rpms but feels like it picks up in the top half or so of the rev range then I would bet an o2 fixes it.

Is the engine factory new? What model is it?
Sorry about that, I had it all in there originally but must have left it out when editing. The engine is a newly built reman engine (all new OEM components other than the block) from SSI out of Michigan. It is the stock 2.5 SOHC, non-turbo. The only difference I'm aware of is the plugged EGR port on the head.

The performance is actually better than I remember it ever being. It pulls harder throughout the entire rpm range, especially down low.
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Old 07-19-2012, 11:24 PM   #5
RaceFaceXC
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2007 No YELLING
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those valve cover vents are part of the PCV system. So is that white sensor. the valve cover vents should go to the intake system after the MAF sensor and before the TB so that it does not waste or re count already metered air in addition to re-combusting blow by and oil vapor. the half black, half white sensor should have a hose connected to the MAF and another to the intake manifold IIRC. the white side connects to the IM, the black side to the PCV valve. The PCV valve should be on the aft facing side of the crank case, to the right side of the case halves split.
*Note: one part of the black side of that sensor assembly is just a mounting lug and no hose connects to it. You can verify this by looking inside of it with a light and see that it is blocked off
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