Response by OEM ECU if see misfires? -Faulty Crankshaft Speed Fluctuation Sensor(CKP)
 

1999 JDM Ferio Vi
D15B2 - 3Stage Vtec: 12v below 2500RPM, 16V -> 5800RPM, Vtec above 5800RPM
130ps.

Had a Faulty Crankshaft Speed Fluctuation (CKP) signal due to wires catching off alternator belt and getting frayed.
Fixed this wiring yesterday.
Disconnected battery, pulled ECU fuse, hit brake pedal(call it superstition), reconnected all - then started and left to idle to normal temp, turned off(to allow to "learn" idle correctly).
Then started again and drove.


A quick drive after fixing it - pretty sure it feels and sounds happier high in the revs and pulls better there. Still dont "hear" Vtec engaging, but its a low mileage engine with standard airbox/exhaust, and it does pull well high in the revs so I'm not worried there. I "think" its a little smoother/more responsive lower in the revs also but this could be placebo and the CKP was only throwing intermittently.

This is my daily driver though so my main concern is actually fuel economy, which I always thought could have been higher.


I'm wondering what the programmed response by the OEM ECU would have been to seeing misfires? From what I read, this is what it would think if there is a problem with the CKP.
- Fueling adjustments?
- "Limp" mode? some stuff I read about the CKP said the car should run like a dog if its not working, but my car ran reasonably ok. My recent commute is only 10mins and under 30mph so wasn't really pushing it.

For reference, this is the CKP:
http://ww2.justanswer.com/uploads/di...023201_cfk.pdf