Wideband Bosch LSU 4.2 versus 4.9
02-12-2016, 07:54 PM
#27
Re: Wideband Bosch LSU 4.2 versus 4.9
a lot of people are scared of extra connections but in reality the difference is negligible if the conection is proper.
if you think about it Honda has 4,5,6 connectors inline without any issues
maybe once you get into aerospace or 500000 high end home stereo systems then you start using a magnifying glass and a microscope to inspect your solders for defects in those situations it matters
but here I wouldn't worry about 3-4-5 connectors in one wire as long as they make a solid connection
I usually dip the wire in flux then crimp it and then solder it and shrink wrap
or take the sleeve off a butt connector crimp it and then shrink wrap it instead
sometimes luckis on my side and this time it was lol
I went to get some connectors and found a MTX-L gauge that someone left so I got that for free, but some idiot cut both harnesses off
so if anyone has a damaged MTX-L or the wires from it I will gladly accept them just tell me how much.
if you think about it Honda has 4,5,6 connectors inline without any issues
maybe once you get into aerospace or 500000 high end home stereo systems then you start using a magnifying glass and a microscope to inspect your solders for defects in those situations it matters
but here I wouldn't worry about 3-4-5 connectors in one wire as long as they make a solid connection
I usually dip the wire in flux then crimp it and then solder it and shrink wrap
or take the sleeve off a butt connector crimp it and then shrink wrap it instead
sometimes luckis on my side and this time it was lol
I went to get some connectors and found a MTX-L gauge that someone left so I got that for free, but some idiot cut both harnesses off
so if anyone has a damaged MTX-L or the wires from it I will gladly accept them just tell me how much.
Last edited by raverx3m; 02-12-2016 at 08:32 PM.
02-14-2016, 08:11 PM
#28
Re: Wideband Bosch LSU 4.2 versus 4.9
Ravex3m did not take it harsh at all. I was just pointing out that there are other reasons as well for the sensor fail. Not just the one you mentioned. The heating control of the sensor is very important.
Also on a side note m4xwellmurd3r just make sure you never leave the sensor off with the engine running. This will also kill a sensor.
Also on a side note m4xwellmurd3r just make sure you never leave the sensor off with the engine running. This will also kill a sensor.
02-22-2016, 11:56 PM
#30
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Re: Wideband Bosch LSU 4.2 versus 4.9
found a great article explaining why so many MTX-L units fail
How to id the sensor
Even with a LSU 4.2, the controller makes a big difference. Bosch sensors are not easy to fail even with a LSU 4.2, if controlled appropriately. Especially, LSU 4.9 is designed for more than 10 year life because it has to, for the vehicle life. It should not fail in short time, like a couple of years. Many OEM cars have been running with LSU 4.9 for years. Why so many aftermarket wideband systems have failed LSU sensors? Because many of them don't have a good heating control strategy. The number 1 failure mode of a LSU sensor is being heated up too fast or too earlier
NRTeam.org
The major difference between LSU 4.9 and 4.2 is that LSU 4.9 uses the reference pumping-current, while LSU 4.2 uses the reference air. What does this mean? Let's read this true story from the auto industries: when Bosch first designed a wideband oxygen sensor, a reference air cell was used to provide a reference of stoic AFR. The technology was to keep the pumping cell balanced with the reference air cell, by pumping the oxygen out of the pumping cell. The pumping current was the indication of the actual AFR in the exhaust gas. The bigger the pumping current, the more the oxygen in the exhaust, and vice versa. Therefore the reference air was vital to the accuracy of the sensor, because it was THE reference. It worked well in the lab, but not so good in the real life, because the environment around the sensor on a car was much worse. The reference air cell was susceptible to be contaminated by the exhaust gas, and / or other surrounding pollutions. Once the reference air was contaminated, the whole characteristics of the sensor were shifted to the low side. It was called "Characteristic Shifted Down", or CSD, in the industries. This was the biggest problem of LSU 4.2 that was used in some early OEM applications. And it caused the big quality issue to Bosch. To fix this problem, Bosch redesigned the LSU sensor, and came up with LSU 4.9 version. LSU 4.9 sensor completely got rid of the reference air. Instead, it used a reference pumping current which was equivalent to the stoic reference air, but without having any physical air in the cell. So the technology became: the actual pumping current was compared to the reference pumping current to maintain the balance. The actual pumping current was still the indication of the actaul AFR, but the reference was a calibrated electrical signal, and stayed same all the time, all the situations.
This is the fundamental difference between the LSU 4.2 and LSU 4.9.
LSU 4.9 gets rid of the reference air, and therefore gets rid of the biggest failure mode. As a result, LSU 4.9 has a long life and can maintain the accuracy throughout the life. Only since then, Bosch LSU sensors have been used widely in the auto industries.
Nowadays, all OEMs who use Bosch O2 sensors are using LSU 4.9. GM, Ford, and Chrysler all use LSU 4.9 now. If you check out the O2 sensors on your recently bought vehicles, cars/SUVs/Pickups, (since 2007 or later), on the exhaust manifolds, you will find out that they are all exclusively LSU 4.9. No more 4.2 sensors can you find on OEM vehicles.
Most aftermarket wideband controllers are still using LSU 4.2, mainly for low cost reasons. Bosch sells the LSU 4.2 to the aftermarket at a much lower price than LSU 4.9. Plus, many of those companies do not want to or are not able to adapt the new LSU 4.9 sensors. There is a big mis-understanding that LSU 4.9 is only for diesel engines, because it can measure very lean AFRs. That's not true. There is a diesel version of LSU 4.9, called LSU4.9D, mainly because of fuel and temperature difference. LSU 4.9 has been widely used with the gasoline engines. In fact, it is the most popular gasoline engine O2 sensor now, not only because it measures wide range of AFR, but also because it has the very good reliability, and high accuracy.
There are a few wideband controller companies in the aftermarket using LSU 4.9. But that does not mean all controllers using LSU 4.9 are equal. Even with the same LSU 4.9 sensor, the controller can make a big difference. Some wideband controllers are designed for AFR display only, and they are named as "wideband AFR gauges" instead of controllers. You can imagine that those wideband gauges do not have good accuracy and fast response rate because they are not designed for those purposes. Those gauges are more for good looking than for engine tuning purposes. For engine controls, the accuracy and response rate are the most critical characteristics of a wideband controller. One way to tell whether a wideband controller is good or not, is to see whether it can be used as a feedback device for the ECU. A feedback device must provide a real-time signal in the fast rate and high accuracy, even under dynamic situations. The requirements for a feedback device are much, much more than those for a gauge.
Even with a LSU 4.2, the controller makes a big difference. Bosch sensors are not easy to fail even with a LSU 4.2, if controlled appropriately. Especially, LSU 4.9 is designed for more than 10 year life because it has to, for the vehicle life. It should not fail in short time, like a couple of years. Many OEM cars have been running with LSU 4.9 for years. Why so many aftermarket wideband systems have failed LSU sensors? Because many of them don't have a good heating control strategy. The number 1 failure mode of a LSU sensor is being heated up too fast or too earlier. O2 sensors are made of ceramic materials, which can be damaged by severe thermal shocks, like condensations, liquid residuals, or just high heating power when it's still cold. A very careful heating strategy to detect the dew point and a close-loop sensor temperature control are vital for the life of the sensors. That's why the LSU sensor must be controlled in the context of engine controls. You may say, only those know engine controls can design a good wideband controller.
How to id the sensor
Even with a LSU 4.2, the controller makes a big difference. Bosch sensors are not easy to fail even with a LSU 4.2, if controlled appropriately. Especially, LSU 4.9 is designed for more than 10 year life because it has to, for the vehicle life. It should not fail in short time, like a couple of years. Many OEM cars have been running with LSU 4.9 for years. Why so many aftermarket wideband systems have failed LSU sensors? Because many of them don't have a good heating control strategy. The number 1 failure mode of a LSU sensor is being heated up too fast or too earlier
NRTeam.org
The major difference between LSU 4.9 and 4.2 is that LSU 4.9 uses the reference pumping-current, while LSU 4.2 uses the reference air. What does this mean? Let's read this true story from the auto industries: when Bosch first designed a wideband oxygen sensor, a reference air cell was used to provide a reference of stoic AFR. The technology was to keep the pumping cell balanced with the reference air cell, by pumping the oxygen out of the pumping cell. The pumping current was the indication of the actual AFR in the exhaust gas. The bigger the pumping current, the more the oxygen in the exhaust, and vice versa. Therefore the reference air was vital to the accuracy of the sensor, because it was THE reference. It worked well in the lab, but not so good in the real life, because the environment around the sensor on a car was much worse. The reference air cell was susceptible to be contaminated by the exhaust gas, and / or other surrounding pollutions. Once the reference air was contaminated, the whole characteristics of the sensor were shifted to the low side. It was called "Characteristic Shifted Down", or CSD, in the industries. This was the biggest problem of LSU 4.2 that was used in some early OEM applications. And it caused the big quality issue to Bosch. To fix this problem, Bosch redesigned the LSU sensor, and came up with LSU 4.9 version. LSU 4.9 sensor completely got rid of the reference air. Instead, it used a reference pumping current which was equivalent to the stoic reference air, but without having any physical air in the cell. So the technology became: the actual pumping current was compared to the reference pumping current to maintain the balance. The actual pumping current was still the indication of the actaul AFR, but the reference was a calibrated electrical signal, and stayed same all the time, all the situations.
This is the fundamental difference between the LSU 4.2 and LSU 4.9.
LSU 4.9 gets rid of the reference air, and therefore gets rid of the biggest failure mode. As a result, LSU 4.9 has a long life and can maintain the accuracy throughout the life. Only since then, Bosch LSU sensors have been used widely in the auto industries.
Nowadays, all OEMs who use Bosch O2 sensors are using LSU 4.9. GM, Ford, and Chrysler all use LSU 4.9 now. If you check out the O2 sensors on your recently bought vehicles, cars/SUVs/Pickups, (since 2007 or later), on the exhaust manifolds, you will find out that they are all exclusively LSU 4.9. No more 4.2 sensors can you find on OEM vehicles.
Most aftermarket wideband controllers are still using LSU 4.2, mainly for low cost reasons. Bosch sells the LSU 4.2 to the aftermarket at a much lower price than LSU 4.9. Plus, many of those companies do not want to or are not able to adapt the new LSU 4.9 sensors. There is a big mis-understanding that LSU 4.9 is only for diesel engines, because it can measure very lean AFRs. That's not true. There is a diesel version of LSU 4.9, called LSU4.9D, mainly because of fuel and temperature difference. LSU 4.9 has been widely used with the gasoline engines. In fact, it is the most popular gasoline engine O2 sensor now, not only because it measures wide range of AFR, but also because it has the very good reliability, and high accuracy.
There are a few wideband controller companies in the aftermarket using LSU 4.9. But that does not mean all controllers using LSU 4.9 are equal. Even with the same LSU 4.9 sensor, the controller can make a big difference. Some wideband controllers are designed for AFR display only, and they are named as "wideband AFR gauges" instead of controllers. You can imagine that those wideband gauges do not have good accuracy and fast response rate because they are not designed for those purposes. Those gauges are more for good looking than for engine tuning purposes. For engine controls, the accuracy and response rate are the most critical characteristics of a wideband controller. One way to tell whether a wideband controller is good or not, is to see whether it can be used as a feedback device for the ECU. A feedback device must provide a real-time signal in the fast rate and high accuracy, even under dynamic situations. The requirements for a feedback device are much, much more than those for a gauge.
Even with a LSU 4.2, the controller makes a big difference. Bosch sensors are not easy to fail even with a LSU 4.2, if controlled appropriately. Especially, LSU 4.9 is designed for more than 10 year life because it has to, for the vehicle life. It should not fail in short time, like a couple of years. Many OEM cars have been running with LSU 4.9 for years. Why so many aftermarket wideband systems have failed LSU sensors? Because many of them don't have a good heating control strategy. The number 1 failure mode of a LSU sensor is being heated up too fast or too earlier. O2 sensors are made of ceramic materials, which can be damaged by severe thermal shocks, like condensations, liquid residuals, or just high heating power when it's still cold. A very careful heating strategy to detect the dew point and a close-loop sensor temperature control are vital for the life of the sensors. That's why the LSU sensor must be controlled in the context of engine controls. You may say, only those know engine controls can design a good wideband controller.
In a clean engine bay; no exhaust leaks and no oil/fuel/fluid spraying around, the 4.2 should offer similar life to the 4.9.
The 4.2 is affected by elevation as the reference cell uses atmospheric free air as a reference. At high altitudes the amount of O2 molecules per volume is less so that results in richer readings. In low altitudes the 4.2 sensor will tend to read more lean. The 4.9 sensor should not have this problem, I have not confirmed this experimentally yet, but based on what I know and what I read this should be the case.
For me personally, I am mostly indifferent to 4.2 vs 4.9, on a performance tuned engine; the sensor's performance will usually be compromised by carbon buildup in the sample chamber way before the reference cell contamination of the 4.2 sensor comes into play. With that said, I would be willing to pay ~$20 premium for a 4.9 sensor over a 4.2 sensor, which is basically what the price delta between the 4.2 and 4.9 is on online shops are right now. Anymore than ~$20 and I would probably stick with a 4.2, of course this assumes you have a controller that can work with both the 4.2 and 4.9. For controller + sensor, again I would only be willing to pay around $20 extra, there is no/minimal cost difference between designing a 4.2 controller vs 4.9 controller, so the price difference would be due to the value of the sensor.
REgards,
Alan To
02-29-2016, 11:50 AM
#31
Re: Wideband Bosch LSU 4.2 versus 4.9
another one bites the dust.
my brand new sensor just went out after only a week of driving on a stock type-r motor that is not running too rich or too lean is wired properly and calibrated again
5 minutes later it slowly creeps to 22.1afr and stays there
I belive that the problem is the gauge itself. it could be a defective circuit or just badly designed controller that doesn't do a good job at the only job it needs to do...
since the people who keep having issues continue having issues with multiple sensors this leads me to belive that the early kits had a faulty design and maybe were fixed later and innovate kept it quiet.
because I don't see how tis lsu4.9 last only a week in a good running motor I didn't even go over 7000 rpm in this yet.
time to switch to different controller like many people on other forums suggested doing after they went through 3-4 sensors and then had no issues with another brand controller
my brand new sensor just went out after only a week of driving on a stock type-r motor that is not running too rich or too lean is wired properly and calibrated again
5 minutes later it slowly creeps to 22.1afr and stays there
I belive that the problem is the gauge itself. it could be a defective circuit or just badly designed controller that doesn't do a good job at the only job it needs to do...
since the people who keep having issues continue having issues with multiple sensors this leads me to belive that the early kits had a faulty design and maybe were fixed later and innovate kept it quiet.
because I don't see how tis lsu4.9 last only a week in a good running motor I didn't even go over 7000 rpm in this yet.
time to switch to different controller like many people on other forums suggested doing after they went through 3-4 sensors and then had no issues with another brand controller
Last edited by raverx3m; 02-29-2016 at 12:14 PM.
02-29-2016, 02:36 PM
#32
03-10-2016, 01:56 AM
#34
Honda-Tech Member
Re: Wideband Bosch LSU 4.2 versus 4.9
Glad my plx came with 4.9 :-)
Only had it in the car a few weeks but I love it so far. Seems solid. Love the ttl output and daisy chaiming of other sensors.
Only had it in the car a few weeks but I love it so far. Seems solid. Love the ttl output and daisy chaiming of other sensors.
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