I'm working on a '95 4Runner 3.0 automatic that is driving me nuts.
It came in because it failed emissions. The report was showing around 4% on CO and 350 on HC (passing is 1.2% CO and 220 HC).
I stuck my tester in the tailpipe and I'm getting 13% CO and 2500 HC! This is ten times the allowable amounts.
There is no engine light on. The engine runs fairly smooth, doesn't seem to have any misfires.
I tapped into the O2 sensor wire and the sensor was moving very slowly from about .3v to .85v. Given that this engine was running crazy rich that seemed odd. I installed a new sensor and now getting a steady .99v reading. So now I have a working O2 but still running rich.
Some things I've tried:
- unplugging the connector at the cold start injector - made no difference in emissions readings.
- I checked to see if the cold start injector was leaking - no.
- I pulled off vacuum lines to create a leak to see if my readings leaned out, which they certainly should have given the engine was sucking so much air it barely ran - made no difference in readings at all.
- I plugged my tester into another car just to make sure it wasn't messed up - other car tested normal.
- Fuel pressure reading showed about 49psi., spec is 38-44, so I suspected a bad regulator. Also, the fuel pressure regulator would not hold vacuum, although it did not seem to be leaking into the vacuum line. I replaced it and that has made no difference.
- I unplugged the 3 injectors that can be reached without removing the intake one by one and this made no difference in emissions readings at all.
- I tapped into the coolant sensor wire and it seems to be working, but I'm not 100% sure what the voltage should be when the car is warmed up.
- I tapped into the air flow meter wire and it too seems to be working (about 2v at idle), but again I'm not positive what it should read at idle.
Any ideas?
One more thing: The transmission (automatic - 4x4) will not shift out of first gear. I doubt this was an issue when the car came in, I'm sure it would have been brought up. Any ideas on what could have caused this? I've had my hands all over and around the intake manifold, is there something around there that could have come disconnected? I can't find anything.
If you read all this, thank you, and I truly appreciate any help you can give.
It came in because it failed emissions. The report was showing around 4% on CO and 350 on HC (passing is 1.2% CO and 220 HC).
I stuck my tester in the tailpipe and I'm getting 13% CO and 2500 HC! This is ten times the allowable amounts.
There is no engine light on. The engine runs fairly smooth, doesn't seem to have any misfires.
I tapped into the O2 sensor wire and the sensor was moving very slowly from about .3v to .85v. Given that this engine was running crazy rich that seemed odd. I installed a new sensor and now getting a steady .99v reading. So now I have a working O2 but still running rich.
Some things I've tried:
- unplugging the connector at the cold start injector - made no difference in emissions readings.
- I checked to see if the cold start injector was leaking - no.
- I pulled off vacuum lines to create a leak to see if my readings leaned out, which they certainly should have given the engine was sucking so much air it barely ran - made no difference in readings at all.
- I plugged my tester into another car just to make sure it wasn't messed up - other car tested normal.
- Fuel pressure reading showed about 49psi., spec is 38-44, so I suspected a bad regulator. Also, the fuel pressure regulator would not hold vacuum, although it did not seem to be leaking into the vacuum line. I replaced it and that has made no difference.
- I unplugged the 3 injectors that can be reached without removing the intake one by one and this made no difference in emissions readings at all.
- I tapped into the coolant sensor wire and it seems to be working, but I'm not 100% sure what the voltage should be when the car is warmed up.
- I tapped into the air flow meter wire and it too seems to be working (about 2v at idle), but again I'm not positive what it should read at idle.
Any ideas?
One more thing: The transmission (automatic - 4x4) will not shift out of first gear. I doubt this was an issue when the car came in, I'm sure it would have been brought up. Any ideas on what could have caused this? I've had my hands all over and around the intake manifold, is there something around there that could have come disconnected? I can't find anything.
If you read all this, thank you, and I truly appreciate any help you can give.
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