Expert: Mike Evans - 10/23/2010

Question
hi i have a 83 Ford bronco with a veriable venturi carberator on it and the smog problem is that at idle it runs way to rich. someone i know says it might be the map sensor or the computer.  

Answer
    The most likely electrical fault would be a bad coolant temp sensor.  A bad CTS causes the EECIV computer to run as though it were cold and just started, i.e. rich.  The other possibility is the carburetor itself.  Variable venturi carburetors are actually quite simple in operation, but very difficult to get adjusted properly.  Many folks will try to fit a model 2150 two-barrel carb and manifold in place of the VV carb.  If you can find a mechanic who knows his VV carbs he can probably fix it without a whole lot of fuss.  Touble is, most of those guys are retired.