PPE vs. Sikky and CEL and HP
#16
PPE: Thanks for chiming in an explaining what's really going on. For not too technical car guys like me, it seemed to make perfect sense at the time.
Having said that, I do have to agree with zojirushi that the fuel economy seemed to drop a little and it's not my right foot either (the novelty has worn off. Now I just drive around normally again). I do believe the car runs a little richer than stock.
Another thing, after replacing the AF sensor, the codes reset by themselves. BUT, the very next day, the codes are back again!!! Same bank 2 sensor 1!!! Now what to do.... any suggestions?
Having said that, I do have to agree with zojirushi that the fuel economy seemed to drop a little and it's not my right foot either (the novelty has worn off. Now I just drive around normally again). I do believe the car runs a little richer than stock.
Another thing, after replacing the AF sensor, the codes reset by themselves. BUT, the very next day, the codes are back again!!! Same bank 2 sensor 1!!! Now what to do.... any suggestions?
Can you email me your exact codes to sales@ppeengineering.com and I will take a look and respond.
#17
Removing the catalytic converters will increase the exhaust smell and can cause carbon buildup on the tips/bumper.
#18
Tech Info Resource
iTrader: (2)
There are four A/F devices in the exhaust stream. Two are wideband planar devices - these are your primary O2 sensors for A/F control. The other two are narrowband sensors only capable of monitoring the catalytic converter's efficiency decline over the years. One pair monitors cylinders 1, 3, 5, and 7; the other pair monitors cylinders 2, 4, 6, and 8.
The methodology Toyota uses to monitor the secondary sensors is far more complex than it used to be in the early days of closed loop feedback. They run a routine during normal operation where the program intentionally runs rich/lean to ensure all the sensors are working. If they fail to respond during this test cycle, a soft DTC is set. If it fails repeatedly, a hard DTC is set and the MIL illuminates. This is why it surely isn't some simple resistor or capacitor making the ECM think everything is OK. Honestly, I'm pretty amazed all the guys running headers don't have issues with MILs, it speaks a lot to the cleverness of what both PPE and Sikky have done to get past this.
Doc - the sensors need to be a few things - first, they need to be installed correctly. That means with the right tools and using the factory torque requirements. Second, they need to have free air available. They ALL work only because one side of the sensor is exposed to ambient air. If the holes are clogged or blocked, or someone got oil or antiseize or some other pollutant in the air vents on the sensors, they will fail. Absolutely 100% of the time, FAIL. This also means if they get water splashed on them, you've got problems. Third, there are multiple codes for failure. If the heater circuit goes bad, it sets a code. If the A/F ratio does not meet the expected value in the table in the ECM, it sets a code. If there is an open or a short in the circuits (yes, there are multiple circuits because you have a heater and either one or two zirconium devices measuring what's going on) you set a code.
Troubleshooting starts with finding out exactly which code(s) is(are) set.
Claiming one or the other header "runs rich" is pretty unlikely unless there is a fatal flaw in where the primary wideband sensor is installed. I didn't see anything like that on either header design.
There are PLENTY of other differences impacting Caymandiver's runs vs. yours. You don't even run the same fuel - there are 200 different local fuel standards for gasoline in the US alone. So, it's just about impossible to draw the conclusions you are from the data we have. Too many other possibilities exist.
Finally, it is impossible for the secondary O2 to impact A/F ratios in any way, so it is impossible for the different SIM designs to be responsible for what you are observing. It's definitely something else.
The methodology Toyota uses to monitor the secondary sensors is far more complex than it used to be in the early days of closed loop feedback. They run a routine during normal operation where the program intentionally runs rich/lean to ensure all the sensors are working. If they fail to respond during this test cycle, a soft DTC is set. If it fails repeatedly, a hard DTC is set and the MIL illuminates. This is why it surely isn't some simple resistor or capacitor making the ECM think everything is OK. Honestly, I'm pretty amazed all the guys running headers don't have issues with MILs, it speaks a lot to the cleverness of what both PPE and Sikky have done to get past this.
Originally Posted by TIS
1. Active Air Fuel Ratio Control
The ECM usually performs air fuel ratio feedback control so that the air fuel ratio sensor output indicates a near stoichiometric air fuel level. This vehicle includes active air fuel ratio control in addition to regular air fuel ratio control. The ECM performs active air fuel ratio control to detect any deterioration in the three-way catalytic converter and heated oxygen sensor malfunctions (refer to the diagram below).
Active air fuel ratio control is performed for approximately 15 to 20 seconds while driving with a warm engine. During active air fuel ratio control, the air fuel ratio is forcibly regulated to become lean or rich by the ECM. If the ECM detects a malfunction, a DTC is set.
The ECM usually performs air fuel ratio feedback control so that the air fuel ratio sensor output indicates a near stoichiometric air fuel level. This vehicle includes active air fuel ratio control in addition to regular air fuel ratio control. The ECM performs active air fuel ratio control to detect any deterioration in the three-way catalytic converter and heated oxygen sensor malfunctions (refer to the diagram below).
Active air fuel ratio control is performed for approximately 15 to 20 seconds while driving with a warm engine. During active air fuel ratio control, the air fuel ratio is forcibly regulated to become lean or rich by the ECM. If the ECM detects a malfunction, a DTC is set.
Troubleshooting starts with finding out exactly which code(s) is(are) set.
Claiming one or the other header "runs rich" is pretty unlikely unless there is a fatal flaw in where the primary wideband sensor is installed. I didn't see anything like that on either header design.
There are PLENTY of other differences impacting Caymandiver's runs vs. yours. You don't even run the same fuel - there are 200 different local fuel standards for gasoline in the US alone. So, it's just about impossible to draw the conclusions you are from the data we have. Too many other possibilities exist.
Finally, it is impossible for the secondary O2 to impact A/F ratios in any way, so it is impossible for the different SIM designs to be responsible for what you are observing. It's definitely something else.
Last edited by lobuxracer; 03-18-14 at 09:25 PM.
#20
11 Second Club
Thread Starter
After replacing the A/F sensor with a brand new A/F sensor all was fine until last week. Got another CEL... but that one went away the next day. If it comes back, I'm going to change the extension. We'll see...
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