Motor, ECU, and Trans: JDM B18C-R/S21 Trans/P73 JDM ITR ECU.

Twice now after the swap I have experienced this problem with my car. The first time was after I hosed out my engine bay, the second (today) while it was pouring rain out. I feel like water is the culprit...

The car runs and drives fine, all the gears engage nicely, but the RPMs don't fall when the clutch is pressed. I would have taken a video but the rain was really bad today. After the rain slowed the problem ceased. I did hit some large puddles, nothing gigantic though.

Example: Cruising at 3500 RPMs in 5th. Stop light coming. Clutch gets pressed in and the RPMs stay at 3500. Then you shift into 1st after the stop and the car goes back down to 800-900 and shifts through the RPMs without dropping, only increasing. Kind of like an automatic transmission...but no RPM drop.

Side notes: The car has died on cold start up 3 times since swap (around a month ago). Gets up to about 1500RPMs then just drops. It can be saved by a light tap on the gas. After the times that it has dies, the second start gives no issues. No CEL.

 

See if you can lift the peddle with your foot from the back if you can and they drop throttle cable is too tight or throttle body is dirty and sticking

 

^^this

should be a little play in the throttle cable.
I think its 1/2" of play but i might be wrong..

1/2" meaning 1/4" each direction


Then again, When its cool out or raining, mine does the same thing.. Idles a little higher as fuel trims are beng adjusted for the cooler air coming in.

 

clean your MAF sensor

 

To do that, he would have to buy and install one. Then make it so the ECU can run/understand it. Then he'd have to clean it.

 

You either have a sticky throttle flap, or a frayed/sticking cable. Clean it with throttle body cleaner/carb cleaner and a rag.

Adjust the throttle cable so it has a little slack.

Brake cleaner is not throttle body or carb cleaner.

 

Sorry, MAP sensor.

lol

 

^lol yes. Not a bad idea to clean the MAP and its port with throttle body or carb cleaner and CAREFUL poking with a paper clip.