I've searched and searched this. I'm hearing some people say it's supposed to be closed, and I've heard others say it's supposed to be slightly open. If it's the latter, then at what angle is it supposed to rest at? I'm wondering because during deceleration and idle, my engine seems to be running rough, I thought my closed throttle plate might be causing it to lean out a bit.

 

BTW, the engine is a B18a w/ a b16 mapped p75 (I know this will cause mixture probs too, that's just how the ecu was when I got it) in an eg.

 

it's supposed to be slightly open. if it's closed you would think it would be hard to start since your not getting any to no air to the motor so i would say slightly open. at least thats the way mine is set up and i have no problems.

 

Come to think of it, when I try to start it it'll die immediately the first few tries. Also when I shut it off, it sounds like it compressed air gets forced out somewhere. So any more info on this? Should I adjust the plate to 90 degrees for WOT, will that cause it to rest in the right position?

 

wot will shut the injectors off if its obd 2. is it? are you sure your mapping matches the B18? you should use the proper ecu. even if the butterfly flap is not open at all there is still a gap around it. my buddy had this issue on his B18C and we just adjusted the idle screw and bam no more idle issues. it would hardly idle or be idling at 4g's. so take a look at those

 

It's OBD1, I believe the block was originally OBD0 from a 90-91 DA because it didn't have a fan switch and has two electrical connectors on the back of the block that don't hook up to my OBD1 engine harness. But I changed everything over and it's OBD1 now. The ecu is an OBD1 P75, but it's been chipped and came with a B16 map already on it unfortunately. The car has ran fine since last February, but recently it seems to be running rough when I'm not giving it any gas... there's a vibration that can be felt through the steering wheel and pedals. I adjusted the screw a while ago and I have it idling pretty consistently at 700-800 rpms. It just seems to run rough when it's in idle range without gas being applied.

 

Just figured out the hissing noise when I shut the car off is air coming out my CAI...