Toyota Supra 2jzge code 25 engine lean, o2 sensors one normal one black any help
What is your question?
Need help/advice Toyota Supra 1993 ge
I'll keep the story short
. Blew head gasket and warped head, replaced both and also replaced spark plugs and leads and the car runs perfect no leaking and doesn't miss or any power loss
. Check engine light with code 25 engine running lean happens each time I drive it and warms up and each time I turn the car off and turn the car on again and start driving for about a minute or so the code comes back on but still no missing or no power loss
. Cleaned the o2 sensors overnight in petrol then drove the car for about an hour to get replacement o2 sensors. Removed the old o2 sensors and one is black while the other looks normal. Drove it home and took the new o2 sensors out to check em and the same problem one looks normal and the other one is black.
. Still getting the running lean code so decided to check all vacuum lines for air leaks and did not discover any leaks
Just hunting for some advice please because I'm close to hitting the wall and running out of ideas
What makes this problem better or worse?
No change with performance or anything
How long has your 1993 Toyota Supra had this problem?
RepairPal Certified shops can diagnose and repair your 1993 Toyota Supra. They provide transparent pricing with a minimum 12-month or 12,000-mile warranty on repairs and services.
Hello,
You are getting a black O2 sensor because the O2 sensors are running in a closed loop, demanding more fuel to correct for the lean running conditions, and the catalytic converter is burning the excess fuel.
I would point to one of two things. The mass airflow sensor reading and the fuel pressure.
Did you install aftermarket/high flow heads?
Did you install a turbo?
Does the car have an aftermarket air intake?
Any other ads-ons for the engine?
Something you can try for vacuum leaks is to put water in a squirt bottle and spray around the engine while the engine is running. Little by little.
If there is a vacuum leak, it will suck up the water, and the engine will sound a little different.
If you did not replace the o-rings for the injectors, I would start there.
Cheers there's nothing aftermarket on it, I've checked for vacuum leaks and there is none I could find, but reinstalling the fuel rail and injectors I did not replace the o rings on the injectors they are the same
Ya, they could have a small leak. Remember, vacuum leaks can occur anywhere that you have suction created by the pistons. Brake booster, valve cover, dipstick, etc.
Also, you might just have a vacuum leak that only exists on the ECM. If the mass airflow sensor is sending battery voltage back to the engine control module, it will certainly report that the engine is receiving tons of air.
Last, don't forget that the intake tube between the mass airflow sensor and throttle body has to be sealed as well, otherwise unmetered air is getting in.
Cheers I'll replace the o rings and replace the tube that attaches to the intake and see what happens , I've checked for vacuum leaks at every vacuum line , every gasket and join on both intake side and exhaust side I haven't discovered any leaks but will go over again and check break booster , dip stick valve covers
Cheers there's nothing aftermarket on it, I've checked for vacuum leaks and there is none I could find, but reinstalling the fuel rail and injectors I did not replace the o rings on the injectors they are the same
Ya, they could have a small leak. Remember, vacuum leaks can occur anywhere that you have suction created by the pistons. Brake booster, valve cover, dipstick, etc. Also, you might just have a vacuum leak that only exists on the ECM. If the mass airflow sensor is sending battery voltage back to the engine control module, it will certainly report that the engine is receiving tons of air. Last, don't forget that the intake tube between the mass airflow sensor and throttle body has to be sealed as well, otherwise unmetered air is getting in.
Cheers I'll replace the o rings and replace the tube that attaches to the intake and see what happens , I've checked for vacuum leaks at every vacuum line , every gasket and join on both intake side and exhaust side I haven't discovered any leaks but will go over again and check break booster , dip stick valve covers