High Co In Ca...smog Help!!

[ParadiseMJ]

My old XJ, 90, 4.0, AW4...now my son's XJ...has been mostly sitting for the last year. Short trips, 'round town a bit, being started and run up to temp every week or so.

 

He had to register it, and get it smogged. Failed smog on CO.

 

Allowed measurment (passing) is 1.0

Measured amount 2.16 (failed) at idle.

Measured amount 2.90 at 2500 rpm (failed) "Gross Polluter" staus

 

So, now he has to take it to a Gross Polluter station to get it smogged and finally register it. It passed all the other tests with great numbers, vacuum, EGR, NoX, etc. all good.

 

My question: Would the Jeep virtually sitting for a year have an effect on the CO levels if he just started it, and then drove only about 2 miles to smog it without the thing ever getting really up to temp?

 

It starts, runs and drives like a champ, no sign of trouble, decent mileage. Would getting it out on the highway and "blowing it out" for a hundred or so miles solve my problem...or does high CO indicate a specific problem??

[JeffN]

Failure for High CO; CO is an indication of a Rich mixture. This is, too much fuel entering into the cylinders or not enough air. If a fuel injector is leaking into a cylinder, that cylinder will be running a richer fuel mixture causing it to run out of air and the flame burn out before the fuel is consumed properly. This is like turning off the vents on your charcoal grill and the fire goes out. The fuel is partially burned but, not all the way consumed. Engine temperature is a factor in how much of the fuel is burned. Cold engines cannot burn the fuel as well as an engine at operating temperature. A variety of sensors are used on the engine to match up the correct amount of fuel and air. Three major sensors report to the Engine Computer ( ECM) and have the biggest impact on allowing the computer to provide the right amount of fuel. The ECT or Engine Coolant temperature sensor reports the coolant temperature. The Mass Airflow Sensor, measures the amount of incoming air into the engine. The O2 or Oxygen Sensor, measures the oxygen content in the exhaust flow so the ECM can adjust the fuel mixture trying to stay at the 14.7 to 1 ratio. Depending on the fuel system your vehicle is running, a leaking Fuel Pressure Regulator diaphragm or Fuel Pressure Sensor out of calibration could be the cause. Oxygen sensors wear out over time. They generally fail towards the lean setting. You engine computer could be richening up the mixture to compensate.

[jimoshel]

We don't have smog tests in Pueblo. My lil bro in Aurora does. He flunked twice, then called me for suggestions.The hotter a engine is, the better chance it will have of passing. I suggested he experiment with placing different sizes of cardboard in front of his radiator until the temp needle would just touch the red zone. He did. He passed first time. Just a thought.

[randomguy310]

I had a friend in socal that would mix methonal , from a sprnt car or modified with his gas and it would burn cleaner for the test so he said but idk... he had a ratio like 5:1 but its been years