cbaumy34

Anyone know why my sensor light goes on and the car revs higher when I turn my heater to the off position? Please advise!

pnoyslimm

sensor light? the square display on the cluster panel?

my guess on high idle(revs higher) you must have some type of vacuum leak air/coolant or both.

NismoPick

Year and model (turbo / n/a) is helpful info...

The sensor light is for the O2 sensor factory check. It's always been OFF until now? Any other lights come on?

I'd start with getting your alternator & battery load checked at your local parts store.

cbaumy34

Its an 82 na and yea its been off since iv owned it. Today is the first time I fired up after storing it all winter.

Gonzo

Idle issue is vacuum leak for sure but the sensor light had to be on before unless you've been messing around with the wiring under the passenger side dash. The sensor light was programmed from the factory to come on at 30,000 miles to have you get the emissions system checked at the dealer. The FSM says to disconnect the green wire with the yellow stripe under the right side dash to turn it off.

cbaumy34

That would make sense in the light I re-conected that wire when I was installing my new carpet. So I will disconnect it tonight and confirm it stay off. Any pointers on vaccum leak finding?

NismoPick

So the light doesn't "go on" when you rev... it's always on, right?
Because you made it sound like it only comes on when you rev the engine (clear description helps for a proper diagnosis).

And for vacuum leaks, well... start by checking all the vacuum lines and intake boots to make sure they are secure, tight, and not cracked.

You can also spray brake cleaner along the intake hoses & listen for a change in RPMs (gets messy).

cbaumy34

The sensor light goes on when I turn my car heater to the all position simultaneously when the heater is turned off the idle starts to rise. Sorry for the poor description. Let me know if that makes more sense.

icice9

is it the heater or it could be the AC compressor. when the AC is turned on the compressor pulley is engaged causing the idle to go down just a little bit. and when turned off the idle rises..

Gonzo

Didn't think of A/C compressor. Icice may be more right in the idle issue.
Myself, I'd try plugging off the vacuum lines to the A/C and see if it still does it. As for locating the leak if that's what it is... a needle nose pliers to pinch off lines at various spots while it's acting up may help. Start at the intake and work your way to the controller, etc. Pinching off the line will cause the idle to return to normal. When you reach a spot that doesn't you know it's in that last section of hose or component. I don't recommend carb cleaner as most people would use. That's old school/shade tree crap and not very safe.
And if needle nose pliers crack a hose.... it NEEDED replaced anyways.

mrprofile

The idle is supposed to go up when the A/C is turned on, to adjust for the added load to the engine

cbaumy34

Well the sensor light is gone after disconnecting the wire .. Now I just need to have some time to find the vac leak. Hopefully next weekend.

PredatorZ

If you suspect a vacuum leak, and your vacuum lines are looking old and brittle, go get yourself about 15 feet of vacuum line and start replacing pieces one at a time. If just the ends have cracking, and the rest of the rubber looks nice and pliable, then just trim off the cracked / brittle ends, there's usually enough slack to allow for that. Might replace the PCV valve too, just for fun. Its ultra cheap. Might have your coil tested too, if its going bad it can cause issues similar to what you have.