EJ25 2000 subaru engine swap issues.

DavidHenry · September 10, 2015

My 2000 Subaru outback engine locked up at 2:00 in the morning at 75 MPH
going south on I-35 close to Dallas, Texas.
All four wheels stopped turning...I had the clutch in within seconds but not
before I nearly had a heart attack. Lucky I had a manual transmission.

I brought the car home to San Antonio on a trailer.

In the next few weeks I found another EJ25 engine at a local Pick and
Pull that was in a 2001 Legacy sedan with an automatic transmission.

Upon taking the engine home I removed the oil pan and heads and checked and

cleaned everything. Replacing seals and timing belt, spark plugs, spark plug
wires, head gaskets, and clutch. .

I used my original fly wheel and intake manifold and all engine wiring.

When I started it I had a bad miss. #3 was not firing even though it had

plenty of spark and compression. And it was sucking fuel. I had to keep it
ABOVE 2000 rpm to keep it running well enough to go around the block.

I spent several days testing everything. It had an engine code of 340 and

341. Cam shaft sensor error so I at first thought I had made a mistake in the
valve timing when I changed the belt. But after I double checked it I could not
find a problem.

I changed the sensor, made no difference. I checked the circuit for continuity.

All was ok in the wiring, I checked and electro cleaned the wiring harness connectors.
Still no improvement.

Finely I took it to a well respected speed shop that is here in the city for

a diagnostic evaluation as half of the cars they modify are Subaru’s.

After half a day driving the tech crazy they gave up and suggested I must

have mechanical problems in the left head #3 and 4...

I took it home and started studying everything I could find on the web and

talking to every Subaru Tech I could find...and then I heard a story about
someone else who had this problem...Seems that Subaru uses a different cam
sprocket for the cars with manual transmissions then they do for ones with
automatic transmissions. Different number and position of the magnets embedded
in the back of the sprocket. I removed the one from my old engine and it had
two magnets about 90 degrees apart. I removed the one from this replacement
engine that had previously been in the car with the automatic transmission and
it had seven!

I changed the sprocket and replaced the timing belt and the engine started

and ran on all cylinders and stopped guzzling fuel.

Ran smooth and sweet.

The computer, Engine Control Unit (ECU) for the Subaru with the manual
transmission is programmed differently than the one for the automatic
transmission.

I had read many posts about engine swaps but no one in any of these posts

have mentioned this very important piece of information.

And the timing sprocket on the crankshaft is different also. The one for the

manual transmission has many teeth while the one for the automatic has only
six.

So any of you who are contemplating swapping engines take note and check

your driver’s side cam sprocket and your crankshaft sprocket before you
spend a week and a lot of money chasing this problem.

AdventureSubaru · September 10, 2015

It's been talked about a few times on here, but the more people are reminded the better. The general rule is to just keep the cam and crank sprockets to match the car as you go. Sorry it took so much frustration to discover that but glad you've got the car back on the road again.