P1259 CEL on after engine swap. 2000 Accord LX

Re

 

Recently I had to swap out my USDM engine for a JDM one after one of
the cylinders gave out on my old engine. The swap went fine but there
is a problem with the VTEC after the swap. The VTEC does not kick in
at all and there is a loss of power.

I reset the CEL light but it comes on as soon as you turn on the car.
I think the VTEC is suppose to kick in at 4000 RPMs if I'm not
mistaken. I checked the connections and the solenoid and everything
seems fine but the oil pressure switch (the green one) was missing
from the JDM engine, there was only a bolt plugging the hole. So I
took the OPS from the old engine but it was banged up and the prongs
were misaligned. I'm still getting the same CEL as soon as I turn the
key.

Would it be wise to buy an OPS from autozone, the aftermarket ones and
try that? or any other ideas..possibly the solenoid itself is bad?

 

P1259 means the oil pressure is low in the VTEC circuit. If the switch is
missing or "banged up", the ECM will be fooled into thinking the pressure
is low and will refuse to activate the VTEC.

Do you mean the MIL illuminates as soon as the key is turned to "II", or
does it come on _after_ the engine starts?

 

Is this a V6 or a 4?

And was the oil pump removed in the replacement engine?

 

The light comes on as soon as it is placed in the "II" position.

It is a 4 cyl engine.

I don't believe the oil pump was removed.