Can't get emission ready
My '13 volt has been an emissions nightmare since I got it with a 100K miles (now @ 197K). When I bought it the car's comprehensive mpg calculated to be 32 and was predominantly ICE driven (10K miles on electric) . Historically, it would get emissions ready after some work; changing oxygen sensors, spark plugs, replaced the Cat with a used one on ebay (that was dumb, I know), seafoam, BG MOA oil treatment, air filter, etc.
But this year, it will not get Cat + oxy sensor ready. OBDII codes present: o2 sensor low voltages, delayed response, 420 catalyst underperforming. The same codes actually with both the original CAT and the used one I bought on ebay. But recently I tried something totally different.
The car always idled bad if the hood was up and running. Sounded a lot like misfires and engine jerks, similar to bad gas. Fine at higher revs with the foot on the pedal idling. Exhaust smell would always find its way into the cabin when stationary and it smelled a little rich. Even if recirculation was on with a charcoal cabin air filter, you always smelled exhaust fumes while stationary. I completely dismantled the intake up the engine block, trying to suffocate the engine to failure at each component to rule out leaks. It wasn't until I got to the throttle body that the engine came close to failure. I took out the intake manifold (very difficult to pull out of the engine compartment), inspected it for damage, and noticed buildup around intake openings on the block. Cleaned the block, replaced the gasket on both the block and between the throttle body and the manifold.
Of note, the intake manifold had traces of engine oil in it and engine oil came out of the exhaust pipe, which I'm guessing was due to the vacuum while pushing the oxygen starved engine to failure. Cleaned carbon buildup off the engine block's intake, used plastic safe spray for the mass airflow and cleaned the injectors with it. The engine smoked for a couple of minutes but has been idling a lot better. Hardly kicks anymore and the mpgs are around 35 - 40 depending on the air temp. But it still will not make the Cat/O2sen ready for emissions testing. I've disconnected the battery, drove it hard in mountain mode on the interstate. The next thing I'm going to try is swapping out the downstream O2 with an used one I replaced earlier to see if it makes a difference.
I have a strange theory that it might an electric problem. When I graph the O2 sensor voltages, both up/downstream, the upstream voltage is strange compared to the downstream. It constantly drops out and jumps back up like there is a problem with the circuit. I've changed the upstream sensor and it's still the same. There is also a high pitch whine through the speakers when power is being generated by the ICE, which has been there since I got it. Needless to say, this has driven me up the wall. Maybe a ground has come off. It had some body work and there may have been a ground that wasn't reattached. I'll have to look through the service manual and see. I was hoping this intake work would be the final fix for my emission woes.
This is scattered logic but any support, direction, suggestions are welcomed. Thank you in advance.
“When we love, we always strive to become better than we are. When we strive to become better than we are, everything around us becomes better too.”
― Paulo Coelho, The Alchemist
My '13 volt has been an emissions nightmare since I got it with a 100K miles (now @ 197K). When I bought it the car's comprehensive mpg calculated to be 32 and was predominantly ICE driven (10K miles on electric) . Historically, it would get emissions ready after some work; changing oxygen sensors, spark plugs, replaced the Cat with a used one on ebay (that was dumb, I know), seafoam, BG MOA oil treatment, air filter, etc.
But this year, it will not get Cat + oxy sensor ready. OBDII codes present: o2 sensor low voltages, delayed response, 420 catalyst underperforming. The same codes actually with both the original CAT and the used one I bought on ebay. But recently I tried something totally different.
The car always idled bad if the hood was up and running. Sounded a lot like misfires and engine jerks, similar to bad gas. Fine at higher revs with the foot on the pedal idling. Exhaust smell would always find its way into the cabin when stationary and it smelled a little rich. Even if recirculation was on with a charcoal cabin air filter, you always smelled exhaust fumes while stationary. I completely dismantled the intake up the engine block, trying to suffocate the engine to failure at each component to rule out leaks. It wasn't until I got to the throttle body that the engine came close to failure. I took out the intake manifold (very difficult to pull out of the engine compartment), inspected it for damage, and noticed buildup around intake openings on the block. Cleaned the block, replaced the gasket on both the block and between the throttle body and the manifold.
Of note, the intake manifold had traces of engine oil in it and engine oil came out of the exhaust pipe, which I'm guessing was due to the vacuum while pushing the oxygen starved engine to failure. Cleaned carbon buildup off the engine block's intake, used plastic safe spray for the mass airflow and cleaned the injectors with it. The engine smoked for a couple of minutes but has been idling a lot better. Hardly kicks anymore and the mpgs are around 35 - 40 depending on the air temp. But it still will not make the Cat/O2sen ready for emissions testing. I've disconnected the battery, drove it hard in mountain mode on the interstate. The next thing I'm going to try is swapping out the downstream O2 with an used one I replaced earlier to see if it makes a difference.
I have a strange theory that it might an electric problem. When I graph the O2 sensor voltages, both up/downstream, the upstream voltage is strange compared to the downstream. It constantly drops out and jumps back up like there is a problem with the circuit. I've changed the upstream sensor and it's still the same. There is also a high pitch whine through the speakers when power is being generated by the ICE, which has been there since I got it. Needless to say, this has driven me up the wall. Maybe a ground has come off. It had some body work and there may have been a ground that wasn't reattached. I'll have to look through the service manual and see. I was hoping this intake work would be the final fix for my emission woes.
This is scattered logic but any support, direction, suggestions are welcomed. Thank you in advance.
“When we love, we always strive to become better than we are. When we strive to become better than we are, everything around us becomes better too.”
― Paulo Coelho, The Alchemist
