HX: no lean burn, no code, no shift light
 

Hey all,

Been a lurker for a while, I wanted to run this by and see if anyone else had this issue with their HX.

The problem: the car stumbles when getting going or at low throttle, will sometimes stall, wont attempt lean burn, and the shift light is intermittent. However WHEN then shift light is working, you can get it into lean burn.
There are no check engine codes or pending codes(although on cold days it throws a valve lift insufficient code). the EGR trap is clear, the EGR valve is operating as it should, and the FSM tests are all conclusive to a healthy EGR system.

Background:
The car is a 1997 civic HX with an S40 transmission from a 2000 HX (originally it had an S20), it recently had a D16Y7 block donor replacement and head rebuild, I trust the head rebuild, and the Y7 block has the same compression (higher deck height, lower piston dish) as the Y5. It doesn't knock and when it sometimes does leanburn it holds it steady.
There is also a brand new L2H2 wide band sensor in it.
Basically, the engine feels solid, and I dont feel the block is the cause of this issue.

I've read some interesting information on here about a sensor on the clutch pedal that tells the ECU when you've pressed the clutch and can cause the ECU to think the clutch is pressed constantly, I've also read that wide band circuit can short out, or that the ECU just keeps the EGR open constantly in really cold weather.

If anyone has any ideas or has dealt with this let me know, thanks!

fixed the shift light. the clutch sensor switch was indeed not pressed in. fixed this with a rubber pad i had sitting around.

lean burn engages now, shift light works.

now its stumbling worse when getting going. im going to take a timing light to it.