O2 sensor slow response fix
Thread Starter
Staging Lane
Joined: Jul 2002
Posts: 58
Likes: 0
From: englishtown n.j.
O2 sensor slow response fix problem: slow O2 sensor reponse with headers installed.
I had a good tune, street cam/head setup and long tube headers with high flow cats. I ran with the PO133, PO153 codes for a year and a half. New O2 sensors (Bosch 13111) did not fix it. My O2 heater circuit was working and fuse was never blown. Checked all relative ground connection (they looked great). No exhaust leaks.
I did not want to spend time revising the tune to fix this and I was due for the NJ inspection.
Heres what worked for me.
If you examine the bosch 13111 O2 sensor it has 3 very small slots in the protective cover over the sensor. These slots are how the exhaust reaches the sensor. Someone had reported better results with Denso O2's. I noticed that they had small holes in the cover instead of these small slots.
I drilled 6 small holes about 0.10 dia. in pairs, in the protective cover between the slots. See pics You must not drill to deep and damage the sensor. I used a drill press, set the stop on it and just broke thru the protective cover.
Installed the new modded sensors and
all is good.
Cleared the computer, ran thru the GM computer ready requirements and I have not had a code or drivability issue since (approx. 500 miles to date).
I don't know how long the sensors will last. But I am good for two years or until I make a new major mod (or the sensor dies).
Give it a try
I had a good tune, street cam/head setup and long tube headers with high flow cats. I ran with the PO133, PO153 codes for a year and a half. New O2 sensors (Bosch 13111) did not fix it. My O2 heater circuit was working and fuse was never blown. Checked all relative ground connection (they looked great). No exhaust leaks.
I did not want to spend time revising the tune to fix this and I was due for the NJ inspection.
Heres what worked for me.
If you examine the bosch 13111 O2 sensor it has 3 very small slots in the protective cover over the sensor. These slots are how the exhaust reaches the sensor. Someone had reported better results with Denso O2's. I noticed that they had small holes in the cover instead of these small slots.
I drilled 6 small holes about 0.10 dia. in pairs, in the protective cover between the slots. See pics You must not drill to deep and damage the sensor. I used a drill press, set the stop on it and just broke thru the protective cover.
Installed the new modded sensors and
all is good.Cleared the computer, ran thru the GM computer ready requirements and I have not had a code or drivability issue since (approx. 500 miles to date).
I don't know how long the sensors will last. But I am good for two years or until I make a new major mod (or the sensor dies).
Give it a try
Thread Starter
Staging Lane
Joined: Jul 2002
Posts: 58
Likes: 0
From: englishtown n.j.
sorry but I don't have any scanning equipment.
It would have been nice to know the before and after.
I did also notice an improvement in cold engine characteristics
ex. below 150 deg coolant temp. I had some hunting for idle as the car came to a stop. When hot this was not there.
It would have been nice to know the before and after.
I did also notice an improvement in cold engine characteristics
ex. below 150 deg coolant temp. I had some hunting for idle as the car came to a stop. When hot this was not there.
Originally Posted by mr. Jones
I did also notice an improvement in cold engine characteristics
ex. below 150 deg coolant temp. I had some hunting for idle as the car came to a stop. When hot this was not there.
ex. below 150 deg coolant temp. I had some hunting for idle as the car came to a stop. When hot this was not there.
Without a drill press what would you suggest?
A Dremel with cutoff discs could slot it finely, a
hacksaw or triangle file by hand. I'd go for the
power tool though, and plenty of shop air to get
rid of metallic residues.
hacksaw or triangle file by hand. I'd go for the
power tool though, and plenty of shop air to get
rid of metallic residues.
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Thread Starter
Staging Lane
Joined: Jul 2002
Posts: 58
Likes: 0
From: englishtown n.j.
Yea the dremel tool should work. just be carful not to cut deep.
I had been following a post here on the bosch O2's with no solutions.
I figured all I had to loose was $80 for a sensor and a little time.
I had been following a post here on the bosch O2's with no solutions.
I figured all I had to loose was $80 for a sensor and a little time.
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Originally Posted by jimmyblue
Good thinking, seems like this will let more heat in to fight
the heat losses through the body. Could you see any
changes to the switching waveforms after doing this?
the heat losses through the body. Could you see any
changes to the switching waveforms after doing this?
However, with non heated sensors, which rely on the exhaust to stay warm, opening the baffles will let more heat into the switching component.
Nevertheless, I will give it it a shot. This problem has been tormenting me ever since the LT's went in.
Thanks for sharing, Mr Jones!
Last edited by ShevrolayZ28; Nov 25, 2006 at 08:46 PM.
If this fixes the slow switching it may put credence to the theory that the problem is that the gases flow past too quickly to be sampled (Assuming that opening up the baffles allows more gas to get into the sensor.), rather than it being a lack-of-sufficient-heat issue.
Thread Starter
Staging Lane
Joined: Jul 2002
Posts: 58
Likes: 0
From: englishtown n.j.
Please post your results.
can anyone post a scan of before and after sensor switching?
can anyone also verify the acuracy or change in air/fuel ratio with a modded sensor.
Thanks
can anyone post a scan of before and after sensor switching?
can anyone also verify the acuracy or change in air/fuel ratio with a modded sensor.
Thanks
Originally Posted by mr. Jones
Please post your results.
can anyone post a scan of before and after sensor switching?
can anyone also verify the acuracy or change in air/fuel ratio with a modded sensor.
Thanks
can anyone post a scan of before and after sensor switching?
can anyone also verify the acuracy or change in air/fuel ratio with a modded sensor.
Thanks
The switching codes seem to be the first thing to
gripe.
With the heated sensor you have the potential for
heat loss to the gas, but I believe more significant
is the conduction loss to the header wall through
the sensor body. The gas heat has to overcome
this, it's evident that the heater power alone can't.
A higher flux of low-grade heat can make up for
the lesser temperature, from cooling, of the gas
if the problem is heat conduction away from the
element.
At least, that's the way I see it and the results
shown so far seem to bear it out.
gripe.
With the heated sensor you have the potential for
heat loss to the gas, but I believe more significant
is the conduction loss to the header wall through
the sensor body. The gas heat has to overcome
this, it's evident that the heater power alone can't.
A higher flux of low-grade heat can make up for
the lesser temperature, from cooling, of the gas
if the problem is heat conduction away from the
element.
At least, that's the way I see it and the results
shown so far seem to bear it out.
I wonder if this would cure a low voltage code that has me puzzled, I installed brand new Vette Bosch O2's but cannot get rid of this low voltage, bank 1 sensor 1. Think it's worth a try?
my car throughs the p1153 slow switch codes for both banks often during the winter....after reading this thread I went and compared the "factory" O2 sensor to the "auto-zone" bosch unit.....the factory unit has 8 slots compared to 3 on the autozone part, not to mention the housing/tip of the factory unit is much larger also! I plan on going back with the dealership on the O2's next go-around.
Originally Posted by gi8e7oi825
Hmm... I like this idea! I will try it with a dremel & vacuum cleaner. If I screw up, I'll take the rear O2s to a local machine shop and run widebands in their place.
Originally Posted by mr. Jones
Please post your results.
can anyone post a scan of before and after sensor switching?
can anyone also verify the acuracy or change in air/fuel ratio with a modded sensor.
Thanks
can anyone post a scan of before and after sensor switching?
can anyone also verify the acuracy or change in air/fuel ratio with a modded sensor.
Thanks