I just got my engine installed and we started her up for a second and she idled at about 2000 rpm's and then starts racing between about 2000 and 3000. And its throwing the check engine light. Now too things that might be affecting such things...

I bypassed that thing on the bottom of the TB (LS TB), cause I heard that just runs coolant through your throttle body to keep it from freezing, so the hoses go straight from the engine block to that sensor on the back of the TB.

Next I still have the fuel pressure at what it was before the swap (~38 psi) but now have 290cc injectors instead of the original 240cc ones, could this be running so rich it is surging, or does the engine not even look at this until it warms up?

BTW its a b20b with ls head and 12:1 pistons and 62404 cams.

Tommorow I'll look at the spark plugs to see how they look, and I'll recheck all the vaccuum lines and check the OBD code.

Thanks,
David

 

you might have a vacuum hose that is open, that might be why it is going up and down. I doubt the injectors would do it, not at idle, they arent that much bigger than stock.