Question about 1993 Ford F150 SuperCab

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1993 f150 5.0 HO2S always lean ? how to fix it, the truck has been dualed and has no cat

No cats with true duals saying heated O2 sensor always lean

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1 Answer

You can not have any vehicle without Cats

First it is against federal laws to remove them

Second you can not be accepted for inspection

Those 2 you know about

You should also know the purpose of the oxygen sensors

They are for fuel injector pulse or fuel trim corrections

So if you have no Cats you have no need for the O2 Sensors
& they can not function & your screwed.

You also can not go to dual exhaust with only one bank being
monitored by only one O2

How did all that get by you?

Posted on Jan 21, 2013

  • Brandon Miller
    Brandon Miller Jan 23, 2013

    its before the cat so, the cat has nothing to do with it



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Posted on Jan 02, 2017

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SOURCE: I Had a p1131 code replaced o2 sensor before cat

vacuum leak in PVC line or clogged PVC. its a leak after the map sensor. o2 sensor is correcting for a lean condition so its adding fuel to your car when the o2 sensor detects the extra air.

Posted on Jul 24, 2010

  • 272 Answers

SOURCE: Car Running lean o2 sensor is fine.

Most likely your MAF sensor is dirty. It is a very delicate wire that reads airflow in your intake and tells the fuel distribution system how much time to open the injectors. Here's a link to some Ford ones so you know what you are looking for.

They can be cleaned, here's a general how too. If you google MAF Sensor clean you'll find videos and lots of helpful hints! Just make sure you remove the sensor from the vehicle and allow it to fully dry before replacing it.
Mass airflow sensors constantly measure the amount of air entering the intake manifold. This lets the engine management computer know how much gasoline to inject into the cylinders for proper combustion. Hot-wire-type sensors, like you have, work by keeping a short piece of wire or film at a constant, elevated temperature. An electrical current is applied to the wire to maintain its temperature; the amount of current necessary to maintain the temperature is proportional to the mass of cool air flowing past it. Sounds complicated, but there are no moving parts and the response rate is very fast. So far, so good.
Eventually, dirt and oily film bake onto the wire, insulating it from the cooler air--and when the engine management computer sees a value for air mass that's too far out of range, it sets an error code. Periodically, there's a cleaning cycle during which the wire is heated to a very high temperature right after engine shutdown. This burns off deposits.
When this cleaning cycle fails to remove all of the contaminants, you're supposed to replace the MAF sensor. According to almost every manufacturer, it's not recommended or even possible to clean the delicate wires. Of course, they're selling those sensors, so their motivation might be suspect. Next time, I'd try cleaning it first--what do you have to lose? I used to use aerosol carb cleaner, but CRC MAF Sensor Cleaner is new and less prone to dissolving other components in the MAF sensor. Do yourself a favor and remove the MAF sensor from the vehicle before attempting to clean it. Also, I'd make sure the air filter housing, air filter and all associated ducting are intact, clean inside and not leaking dirt. This will keep you from needing to clean or replace the MAF sensor anytime soon.

Posted on Jun 03, 2009

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1 Answer

On a Volkswagen Beetle 1999 2.0 is the first cylinder considered upstream or Downstream when replacing the O2 sensor I'm getting a error code reading of P0171 system too lean (Bank 1)

code p 0171 refers to system too lean bank 1=== causes ---intake /exhaust leak---AIR system--MAF/VAF sensor---fuel pressure/pump---injector/s---heated oxygen (HO2S) sensor
the HO2S is the unit that controls the mixture and is located in the exhaust manifold / pipe before the cat converter

the oxygen (O2S) is just like a final trim and reads the cat converter operation and is located after the cat converter

bank one is closest to the fire wall

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Which O2 sensor is needed for The code P1135 tOYOTA aVALON 2002

code p 0035 refers to heated oxygen sensor(HO2S)--LH front ---heater circuit malfunction===causes ---wiring--HO2S--air induction system---fuel pressure ----injector/s---ECM
heated oxygen sensors are always located in the exhaust manifold/pipe before the cat converter
they control the fuel/air ratio parameters for the ECM to get best burn of the mixture
Oxygen sensor (O2) is always after the cat converter and sets the parameters for the cat burn off

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the back manifold ( closest to the fire wall) is bank l
there are not 2 x O2 sensors up stream
they are heated oxygen sensors (HO2S) and are in the manifold or exhaust pipe before the cat converter
The 2 x O2 sensors are after the cat converter in the exhaust pipe
so bank 1 sensor 1 is a HO2S sensor
there is a difference in the sensors as the HO2S report exhaust gas conditions to the ECM for fuel /air adjustments , have 4 wires and are heated to read the gas correctly
the after cat converter sensors ar O2 sensors and report on the cat converter action to further adjust the air /fuel mix in the ECM

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DTC 2274 02 Sensor stuck on lean bank 1 Sensor 3. Does anyone know what sensor is 3. Is that the one on the exhaust manifold.

O2 sensors are the ones after the cat converter
As they are wired differently to HO2S sensors ( before the cat converter) the ECM knows which sensor is doing the reporting
with a bank 1 reading you should have a v6 or v8 engine in nwhich there will be 4 sensors -- 2 HO2S ( before the cat converter ) and 2 O2 sensors after the cat converter

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1 Answer

What are the probable causes of DTC P1283?

code p1283 refers to heated oxygen sensor(HO2S) bank 2--lean mixture ===causes ---HO2S---fuel pressure --injectors---intake air leak
the HO2S sensor is the one immediately in the exhaust manifold or before the cat converter ---you have changed the wrong unit and that is why there has been no change ( on a v 6 bank 2 is the bank at the grill side )
both the HO2S and the O2 sensor report on the air /fuel mixture to the ECM which makes the changes so it would be true to say that .
check all vacuum hoses for cracks or loose and check the vent controls hoses as well as any leak there will alter the mixture ratio and make it difficult for the ECM to maintain correct air/fuel ratio

Aug 09, 2015 | 2005 Infiniti G35

1 Answer

How many o2 sensore are on the 99 bravado? I replaced the o2 sensor before the cat converter, now code says bank one( before cat.) needs replacing. are there 4?

the sensor before the cat is NOT an O2 sensor but a HO2S sensor ( two different sensors with different operations). If this is a V6 engine there are 4 sensors -- 2 --HO2S sensors before the cats --one for each bank cat and 2 O2 sensors after the cats.
The fault code would have spelt out the correct sensor for replacing

Jan 24, 2015 | 1999 Oldsmobile Bravada

1 Answer

O2 sensor?

O2 sensors are always after the cat converter and HO2S sensors are always before the cat converter.
p0135 refers to heated oxygen sensor(HO2S) 1 bank 1-heater control--circuit malfunction
If it is a straight 6 cylinder engine with 2 cat converters it will be the sensor before the cat converter that connects to the manifold from pistons 1.2.3
If it is a V6 it will be the sensor that is in front of the cat converter that connects to the rear bank pistons 1.2.3. Use the special socket when removing/replacing the sensors to prevent wiring damage

Apr 23, 2014 | 2004 Chevrolet Silverado 2500HD

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I have an 05 Avalanche 5.3, I want to remove Cats and true dual the truck with a pair of MagnaFlow 44's, what problems if any will I run into and is the a kit out there to trick the O2's?...

couple of things you might want to consider
its against the law
cats don't affect performance
the O2 sensors don't know or care about the cats
if you want a true dual exhaust have it built with dual cats installed

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My 2000 Toyo. Tacoma Prerunner TRD V6, truck Failed smog due to the part #3 Functional Computer Tests due to an erased MIL. But had passed the Visual Inspection, and Emissions. So i bought a Code reader...

there are 2 sensors in the system
one is a heated oxygen sensor (HO2S) in the exhaust manifold / pipe before the cat converter that reports the exhaust gas composition to the ECM so that fuel/ air ratios can be adjusted
if that one is faulty it is most likely the reason for running lean or rich
the second sensor is the oxygen sensor (O2) which is after the cat converter and reads the results of the cat converter cleaning the exhaust
you may have to replace both the sensors to get a clearance or replace the cat converter as well as the HO2S unit

Jun 02, 2017 | 2000 Toyota Tacoma PreRunner

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My 1999 Sonoma with the 4.3 is having power/acceleration problems. I get four fault codes that will flag my check engine light on occasion they are, P0171, P0174, P0151, and P0154. I have changed the...

probably changed the wrong sensors
The units you should have replaced are the heated oxygen sensors in the exhaust manifold before the cat converters (HO2S)
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