So I just finished my B20Z swap and finally got it running, sort of. It stays running when it's warming up, but it's not the smoothest idle. Once it's warm the idle is super low (barely turning to 500 rpm) and there is a slight fluctuation (200 rpm) Nothing like the IAC surge. Then it will all of sudden idle at 1K for 10secs or so, and die. It revs fine, seems to have normal power, etc. I have to keep my foot on the gas to keep it running and it will die as soon as I'm off the gas.
If I unplug the MAP sensor, it runs fine. I know that is sending it into open loop.

Computer and Harness are from my '94 Integra LS and were running the B18B1 in the EG perfectly fine.

Swapped the MAP sensor from the old B18

FITV has been deleted, just like on the B18

Timing has been set

O2 sensor was a new Denso last year. Have not tried unplugging this yet.

MAP sensor plug is correct, because it comes from the car, not the harness.

Using B20Z IM and TB

I'm going to continue to check things today, but figured I'd ask the larger community here for any tips they had. TIA

 

What box are you using?

 

What do you mean with box?

I've found unplugging the MAP and starting the car is the only way to make the car run right. Checked for a clogged port for the MAP and it was perfectly clean. I'm running out of ideas. Nothing else makes a difference.

 

Is the check engine light on otherwise?

 

With everything plugged in the check engine light is off, and it idles at around 400 rpm when warm. Then it will recover for 10-20 secs and then drop out and try to die.

 

bump

 

no one has a clue huh?

 

i mean what ecu are you using?

 

P75 I was using with the last engine. also swapped in a PR4 I use for testing to make sure something wasnt wrong with the ecu, but didnt change anything.

 

Have you tried scanning for codes just in case?

 

Only time the check engine light comes on is when something is unplugged. Otherwise when the service connector is jumped, the light is solid. I checked all the wiring for the MAP and it checked out.
Could a vacuum leak cause a low, rough idle? Usually that causes a high idle.