Wife 06 Pontiac Torrent which is the same as a Chevy Equinox has started what I call running rich. I hate to say it but I work on heavy equip but don't have the time or tech knowledge to get at my own cars. The check engine light was on so I took it to my trusted car guy and they ran all the tests. Said the code was for "misfire" and with high miles on plugs-car has 100k, plugs had 60k, they put in plugs, two weeks later problem still there but NO light. It runs great! Exhaust smells like a stuck choke not rotten eggy and every few hot starts it starts like its flooded. Took it back they ran all tests three times, cleaned the throttle plate?, and put two techs on it. Still smells and starts hard now and then. Mileage has dropped off also. Fuel filter is in tank. And still no light on.
- Thread starter redtom
- Start date
Bryan inIowa
Member
Thats a tough one unless it's in front of you . Too many variables to just start tossing out guesses. Did they look at fuel trims ? Coul dhave dripping injector or fuel regulator leaking . A MOTORVAC injector cleaning maydo it some good.
Some thing to check is the breather tube from the air intake to the back valve cover. They come loose from the valve cover and cause a lean code. PCM think lean and richs the fuel up. Also check the pcv elbo at the pcv valve. They get soft. Any thing else you need a scaner to see. Check mass air flow sensor? hope this helps David
MarkB_MI
Well-known Member
- Location
- Motown USA
"Running rich" and "no check engine light" doesn't compute. If it's truly running rich, it's running open loop, which should certainly set the check engine light, and show up on a scan. Did you happen to check and see if the light turns on when you first turn the key? Removing the bulb is a surefire way to clear a check engine light. Your mechanic did SOMETHING to fix the check engine light, and I don't think changing the spark plugs had any effect on your problem.
Bryan inIowa
Member
Lot of drivability concerns will not set a code.
Dave Sherburne NY
Well-known Member
Why don't you ask "Skeeter". I listen to his show every week on the internet, any day I can fit it in. You can Email your question to him too.
Texas car doctor
Texas car doctor
MarkB_MI
Well-known Member
- Location
- Motown USA
Yes, he cleared the codes, but if it's running open loop it should reset them. Either it's running rich and open loop or it's running closed loop. There ain't no in-between.
MarkB_MI
Well-known Member
- Location
- Motown USA
Sorry Russ, but you do not understand the meaning of "closed loop".
Bryan inIowa
Member
Open loop refers to engine running on limited fuel and ingnition strategys . Codes will only set if hard failure @ bad connection , no voltage etc. Closed loop , computer takes total control of fuel and ignition. Codes can set anytime sensor sees reading out of parameter. However,can have several drive concerns without tripping code.
MarkB_MI
Well-known Member
- Location
- Motown USA
Close. "closed loop" is an ancient control systems term that predates electronic engine controls by fifty years or more. It refers to the presence of a feedback loop in a system. Mechanical engine governors are one example of a feedback loop. That is, the output of a system is fed back, inverted, to the system's input.
There are many feedback loops in a modern engine control system, but the main one is the oxygen sensor. The O2 sensor detects the presence of oxygen in the exhaust, and the ECM increases or decreases the amount of fuel to achieve the desired air/fuel ratio. By definition, if there is unburned fuel in the exhaust, the feedback loop is broken and the engine is running open loop. (I'm not convinced this is the case here. It could be that it's not running rich at all.)
There are many feedback loops in a modern engine control system, but the main one is the oxygen sensor. The O2 sensor detects the presence of oxygen in the exhaust, and the ECM increases or decreases the amount of fuel to achieve the desired air/fuel ratio. By definition, if there is unburned fuel in the exhaust, the feedback loop is broken and the engine is running open loop. (I'm not convinced this is the case here. It could be that it's not running rich at all.)
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