Hi, I have a 91 hatch std wit a poor man's type r motor and a obd1 p28 tuned ecm. I just went threw my motor and trans. the speedo cable snapped and the cel light is on before I crank the engine. No vtec, 1-2 gear the two step kicks in down the road. my question is does the ecm see a signal from the odometer for vtec not to work cause of no speed? Or Maby in limp mode? I jumpered the two pins and the cel light stays solid?

 

Someone has to be knowledgable on here!

 

It doesn't look for a signal from the odometer, but it does look for one from the speedometer.
The ECU needs to detect speed, rpm, oil pressure, and engine temp before it will engage vtec.
Limp mode will also take you out of vtec operation.

Solid CEL is usually a faulty ECU. Odd that you are throwing that code since the engine is running... sort of. Doesn't sound right.

 

sounds like you are jumping the wrong connector...the one is for timing, and then there is a wire you need to ground to blink codes on the dash. mine is yellow, depends on your conversion harness.

 

K thanks. I'll look more into that yellow wire and after I replace the speedo cable!

 

Not sure what harness would have 2 individual sets of wires for this, but the single pin on the ECU that performs both of these functions is D4
When D4 is grounded, it retrieves CEL codes and disables ignition advance.