P0130, low MPG, and a rogue vacuum hose

[Davidadav]

Hi all,

I have a 1997 Limited (stock, no lift, 265/75 R16s) and have been troubleshooting a variety of annoyances, including a P0130 and low gas mileage (getting around 11). I replaced both the front and rear O2 sensors with the recommended Denso parts (234-4154 and 234-4162), and saw no improvement. If anything, my MPG seems to be slightly worse, but it may be in my head. I’ve cleaned the MAF sensor as well.

What I found strange was that the O2 sensors did not look like the sensors shown in every O2 sensor pic I’ve seen (stole a pic off the web, as I didn’t think to snap a pic of mine):




One had a longer cable, as expected, but both looked like the picture above, rather than having the longer 1” sensor tube.

Since replacing these, I’m consistently seeing a P0130, which got me checking my vacuum hoses. Strangely enough, I found a hose in my engine compartment, not connected to anything, and for the life of me, cannot figure out where it goes. It could be a prior mechanic replaced the hose and accidentally dropped the old one, or…? Does anyone know where this one should go?




My next step, assuming this is an old hose and not one that somehow fell out, is to check for leaks. My engine is running fine, no misfires, strange noise, etc. Acceleration is loud and sluggish, but…it’s a stock 4Runner.

Any ideas?

Thank you.


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[Bad Luck]

Hi all,

I have a 1997 Limited (stock, no lift, 265/75 R16s) and have been troubleshooting a variety of annoyances, including a P0130 and low gas mileage (getting around 11). I replaced both the front and rear O2 sensors with the recommended Denso parts (234-4154 and 234-4162), and saw no improvement. If anything, my MPG seems to be slightly worse, but it may be in my head. I’ve cleaned the MAF sensor as well.

What I found strange was that the O2 sensors did not look like the sensors shown in every O2 sensor pic I’ve seen (stole a pic off the web, as I didn’t think to snap a pic of mine):



One had a longer cable, as expected, but both looked like the picture above, rather than having the longer 1” sensor tube.

Since replacing these, I’m consistently seeing a P0130, which got me checking my vacuum hoses. Strangely enough, I found a hose in my engine compartment, not connected to anything, and for the life of me, cannot figure out where it goes. It could be a prior mechanic replaced the hose and accidentally dropped the old one, or…? Does anyone know where this one should go?




My next step, assuming this is an old hose and not one that somehow fell out, is to check for leaks. My engine is running fine, no misfires, strange noise, etc. Acceleration is loud and sluggish, but…it’s a stock 4Runner.

Any ideas?

Thank you.

P0130 dtc is for bank 1 sensor 1 oxygen sensor circuit. For our vehicles we only have one bank so this code is for the upstream oxygen sensor (air/fuel sensor) circuit. It's a circuit code not a performance code so i would be checking circuit continuity and voltages. If you are unfamiliar with circuit testing I would recommend taking it to a knowledgeable mechanic.

EDIT: Where did you get the denso sensors from? Are you 2wd or 4wd?

 

[Davidadav]

P0130 dtc is for bank 1 sensor 1 oxygen sensor circuit. For our vehicles we only have one bank so this code is for the upstream oxygen sensor (air/fuel sensor) circuit. It's a circuit code not a performance code so i would be checking circuit continuity and voltages. If you are unfamiliar with circuit testing I would recommend taking it to a knowledgeable mechanic.

EDIT: Where did you get the denso sensors from? Are you 2wd or 4wd?

Thank you, and good shout. I will check continuity and voltage to see if it checks out.

I purchased the Denso sensors off of Amazon (eek). I’m an automatic 4WD V6.


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[Bad Luck]

Thank you, and good shout. I will check continuity and voltage to see if it checks out.

I purchased the Denso sensors off of Amazon (eek). I’m an automatic 4WD V6.


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That's the correct sensor part numbers for 4wd. I've gotten counterfeit Denso on Amazon and eBay before so I try to stick with more reputable sellers like summit racing. If you still have your old sensor you might try swapping it back in and see if your code goes away. There could be an issue with your new sensor wiring which you may be able to find by comparing resistance readings between new and old sensors.

 

[Davidadav]

That's the correct sensor part numbers for 4wd. I've gotten counterfeit Denso on Amazon and eBay before so I try to stick with more reputable sellers like summit racing. If you still have your old sensor you might try swapping it back in and see if your code goes away. There could be an issue with your new sensor wiring which you may be able to find by comparing resistance readings between new and old sensors.

Nice. Thank you for confirming. I really appreciate the info!

Just curious, any thoughts on the vacuum hose?


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[Bad Luck]

Nice. Thank you for confirming. I really appreciate the info!

Just curious, any thoughts on the vacuum hose?


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You're welcome. The size makes me think it may have something to do with the charcoal canister/evap stuff on the driver side of the engine bay

 

[Davidadav]

Excellent - thanks. Well, I know what I’m doing when I’m done with work for the day!


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[19963.4lsr5]

Put your scanner on it and watch the O2 sensor voltage and how it behaves.

From a cold start the pull-up resistor should maintain something like .6v. As the sensor warms up from the heater and exhaust temp the voltage will start to shift up towards the rich end. As soon As the pcm sees a valid O2 reading it will go closed loop.

Watch your voltage and the closed loop monitor. It sounds like your staying open loop. And that isn’t good for your engine oil.

You can easily gas your oil driving a lot in fuel enrichment mode.


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[Davidadav]

Interesting. Well, I picked up a new Denso 234-4162 and the difference is noticeable. The error is gone, my instant MPG is noticeably higher (watching my Ultra Gauge), and after a number of long drives around town I’m seeing a significantly higher average MPG. Looks like I got either a defective of counterfeit sensor.

Still no idea where that hose came from, but my initial problem seems to be resolved.

Regarding staying open loop, according to my Ultra Gauge I’m staying closed loop, so I think I’m good there. Looks like a bad sensor…

Thanks again for the feedback and advice!


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