Hi Scotty,
I've recently had some issues with my 2013 Corolla. First of all, as I use it for Uber as well as personal driving, I have 260 K original engine and transmission with all regular maintenance. About a month ago, I had the check engine go off and thr car started to sputter and such. Cannot remember the code, but ended up replacing plugs, coils, and the number 4 injector. A fweek or so ago, check engine came on again and told it was the upper 02 sensor needing replaced. Car backfired last night and check engine light flashed fir a min. Codes were p219a and po304. My mechanic says both 02 sensors need replaced as well as a fuel filter. Also said since I burn a quart of oil every 750 miles (a out a week's time) says the valves and piston rings are wearing out and suggest a compression test. No manor leaks. Not overheating. Runs fine makes no strange noises. What are your thoughts? Ideas and suggestions? Thanks.
Well if you're burning that much oil you may be fighting a losing battle. However it would be worth changing the PCV valve before declaring the engine worn out unless a compression and/or leakdown test has been performed confirming that diagnosis.
What are the O2 sensor outputs? That will tell you if they're actually bad. For that matter is there anything in the live data or freeze frame data that looks suspicious?
Here's information about the P219a code and possible causes:
https://obd2pros.com/dtc-codes/p219a/
(Probably the P0304 is a symptom of whatever is causing the P219a.)
I'm planning to do a compression and cinder head leak test next week to rule it out ot not. I'm not sure of the 02 outputs. My mechanic says it's the upward sensor. I've read some stories where people drove on bad 02 sensors for years and after replacing them, they started running rough despite a computer reset. I'm not sure what to say about it?
A properly functioning upstream O2 sensor is required for the fuel injection system to maintain the correct air/fuel mixture. If that O2 sensor is bad the engine won't run right. (The downstream sensor only checks on the catalyst and doesn't affect the way the engine runs.)
What would be normal compression numbers when the engine is tested? I read no lower than 130 psi and should be at least 160 to around 200
Thanks
What would be normal compression numbers when the engine is tested? I read no lower than 130 psi and should be at least 160 to around 200
If compression is supposed to be 160-200 and you're seeing as low as 130 there's a problem. Are the compression readings at least reasonably even? The general rule of thumb is all cylinders should be within 10% of each other. (The actual compression specification should be in the shop manual.)
Hi, Continued saga. Compression test was done and no concerns there. Car has been running fine since until today when the check engine started blinking and engine sputtered and stuttered for a minute or so. Pulled over and turned the car off. Started it up and no more check engine light and ran fine. Took it to mechanic who said the old cylinder 4 code misfire read but nothing new. Plugs, wires, and injector fine. Says front 02 sensor is not the culprit, but possibly the ECU is starting to malfunction. Nev had one of those go out. Any ideas or opjnjons?
Have you gone through the troubleshooting section of the site FAQ? There are many things that can cause misfires.
My mechanic claims they have done all the troubleshooting and think maybe the ECU is malfunctioning and sending bad signals which causes a misfire. He has rest the check engine light to see it goes off and will rescan it then. I know some myself on auto mechanics and diagnostics, but no expert. I appreciate what you do to help.