My engine check light went off and i notice that my MPH gauge stop functioning, as well as the idle is at 1000rpm rather then the 500rpm. Any idea of the problem? Can the speedo cable give off a check light? Thanks

 

The speedo itself not working will not give you a check light but vtec will not kick in. You will only see a check light if you drive the car and rev past the vtec point so that might be why you are getting one. Get that speedo fix and you should be good. By the way, you should not be idling at 500rpm.

 

thanks, i have a 91 DA b18a1 btw

 

Just another input from experience...
That's not 100% true, when my alternator was going out and when my secondary 02 wires were melting on the pipping and grounding out, my speedo wasn't working but vtec was still kicking in.


But since you're talking about your DA then yah, he's right, 99% of the time, when speedo doesn't work, vtec doesn't kick in.