Heated O2 Sensor in Modified Exhaust Write Up - Performance Forum

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Heated O2 Sensor in Modified Exhaust Write Up
Saturday, March 10, 2007 2:04 PM
I am running a turbocharged 2.4L with 2.5" exhaust no cat and straight through Magnaflow muffler on a 2002 Cavalier. The car takes about 10 minutes to warm up enough to go into closed loop. When the car goes into closed loop when it is cold it sounds like it wants to stall. The engine rpms go down to about 800 and then it catches itself. I have watched on a scanner what it is doing. As soon as it enters closed loop the Short Term Fuel Trims drop down to about -20 which is causing the problem and slowly climbs back up to the normal -4 to +4. Also if I go and take off without letting the car fully warm up it will hesitate in between shifts. Even with it fully warm it will hesitate a tiny little bit between shifts. The cause for this is the O2 sensor. When you modify an exhaust to make it flow better the O2 sensor does not reach the temperature it needs to. I have spent lots of money on buying the OEM O2 Sensors and this still did not fix it.

The solution to this problem is to install a Heated 4-wire O2 sensor in place of the stock 2-wire O2 Sensor.

This will work for anyone who is running a modified exhaust either N/A or Boosted.

I went out and bought a Universal Bosch 4-wire O2 Sensor Part # 15729 and wired it up. This cost me about $60 at the local parts store. You have to cut the factory O2 Sensor wires and use the plug off of it. The black wire on the new sensor is the signal wire. This gets attached to the Black wire on the factory sensor plug that you have cut off the sensor. The Gray wire on the new sensor gets attached to the gray wire on the factory sensor plug that you cut off the factory sensor. Now you must locate the plug for the rear O2 Sensor after the cat. There will be 2 brown wires on the harness side of the plug. On the other side of the plug these wires turn into 1 black and 1 brown. There is no polarity on these wires. Now you must attach both of the white wires from the new sensor to the 2 brown wires (I chose not to tap into the wires on the sensor side of the plug because it is a $170 sensor from GM).

I noticed a huge difference in thew way the fuel trims were acting right after the installation. They are so much closer and faster now. The car goes into Closed loop in under a minute when it is cold from sitting over night. And there is no more hesitation between shifts.



Edited 1 time(s). Last edited Saturday, March 10, 2007 2:05 PM



Re: Heated O2 Sensor in Modified Exhaust Write Up
Saturday, March 10, 2007 2:36 PM
Nice info man.. Ill keep an eye on this thread if I have any problems after we start the car next week for the first time with boost.











~2014 New Z under the knife, same heart different body~
______________________
WHITECAVY no more
2012 numbers - 4SPD AUTOMATIC!!
328 HP
306 TQ
Re: Heated O2 Sensor in Modified Exhaust Write Up
Sunday, March 11, 2007 4:20 PM
DCStang67 wrote:

The black wire on the new sensor is the signal wire. This gets attached to the Black wire on the factory sensor plug that you have cut off the sensor. The Gray wire on the new sensor gets attached to the gray wire on the factory sensor plug that you cut off the factory sensor.


Umm..your factory sensor is a two wire? Mine is only a one and the one wire is purple. But from the sounds of it the black wire is the signal, so it would be the purple on mine and what would the grey wire go to?

The one I bought is for a 98 GP GTP, and the four colors I have are also black, grey, and two whites but I cant find anywhere telling what each one is. I know there is supposed to be a power, a ground, and a high and low signal but I'm not sure which is which, anyone know?



Re: Heated O2 Sensor in Modified Exhaust Write Up
Sunday, March 11, 2007 4:36 PM
I was thinking about doing this.

Let me see if i am reading this right.
So you bought a self heating o2 sensor, hooked the 2 wires up to the original plug and then used the same power wires from the 2nd sensor behind the cat?

Do you have to use those wires or will any power source that turns on with the PCM work?

PSN ID: Phatchance249

Re: Heated O2 Sensor in Modified Exhaust Write Up
Sunday, March 11, 2007 5:44 PM
Nice right up. I have been thinking of doing this and exactly the same way (except for using a Ecotec heated O2 sensor).

Quote:

Nice info man.. Ill keep an eye on this thread if I have any problems after we start the car next week for the first time with boost.


You have a 95-99 J. You have a 1 wire O2 sensor. He has a 2 wire (2000+) as wel I do. For you pre-2000 J's there is a kit for a heated O2 sensor. It has been posted before on here. It is like $70 (including the sensor) It plugs into your factory harness and then a ground and apower (I think).

Can you post pictures of this? Glad to see it is working. I really need to do this.



FU Tuning



Re: Heated O2 Sensor in Modified Exhaust Write Up
Sunday, March 11, 2007 8:50 PM
I did this two years ago when my cold startup blew chunks with the new turbo and downpipe... seems the stock sensor didn't like being 20 inches away from the head.

EnviouZ, I'm still looking for those diagrams for you.

I'm running the 4 wire GTP sensor... the car runs great and it stopped trying to stall at lights. A great mod.

-Chris-



-Sweetness-
-Turbocharged-
Slowly but surely may some day win this race...
Re: Heated O2 Sensor in Modified Exhaust Write Up
Sunday, March 11, 2007 10:04 PM
Yeah, I'm having that problem with my Cav. I would like to do this also, but I have a 1 wire O2 sensor. I found a retrofit kit from Caspers Electronics here: Kit

Anyone know exactly how it works? I'd rather save myself some money and make my own...Just need to know which wires go where.



2010 Subaru Impreza WRX Limited
1999 Cavalier Z24 Supercharged
1999 Grand AM SE (Beater Car)
1997 GMC Sierra
2007 Honda CBR 600RR
2005 Honda TRX450R
Re: Heated O2 Sensor in Modified Exhaust Write Up
Monday, March 12, 2007 12:53 AM
The reason I used a Bosch instead of a GM 4 wire is because of the price. GM 4 wire is $170 and Bosch universal 4 wire is only $60. and it comes with a watertight connector to splice the wires and instructions that tell you what wire does what.

It looks like you can use the same 4 wire sensor that I used. You hook up the black (signal) wire to your black wire on the original sensor harness. The gray wire (ground) goes to a ground source. One white wire (heater ground) either one goes to a ground source. The last white wire (heater power) hooks to a power wire switched on with the ignition. You can also tap into the second O2 sensor harness like I did for the heater ground and heater power. I found it easier that way because I didn't have to search for an ignition switched power wire. I have not tested this. I am only using the information that was on the paperwork that came with the new sensor.

The paperwork that came with the sensor says,

Black is the signal
2 white wires are heater wires (one switched positive with ignition, one ground)
Gray wire is ground



Re: Heated O2 Sensor in Modified Exhaust Write Up
Monday, March 12, 2007 4:30 AM
Luke Heier wrote:

Yeah, I'm having that problem with my Cav. I would like to do this also, but I have a 1 wire O2 sensor. I found a retrofit kit from Caspers Electronics here: Kit

Anyone know exactly how it works? I'd rather save myself some money and make my own...Just need to know which wires go where.


That is the kit, for the money I would go with it. You only have 2 wires to hook up.

Quote:

http://www.boomboombatteries.com/ProductDetails.asp?ProductCode=4200%5FBP


I found a Ecotec O2 locally for $70. Also a GTP O2 for about the same as well.



FU Tuning



Re: Heated O2 Sensor in Modified Exhaust Write Up
Monday, March 12, 2007 5:09 AM
It's best if you connect the ground (grey) wire from the sensor to the engine block. The ecm / pcm connection for "O2 sensor ground" is on the block, and connecting to the body or to the exhaust itself could introduce signal errors.

If you spend time playing around you can often find Delco heated O2 sensors from different applications for less $$. Generally the 2 differences are the length of the harness and the type of connector used.

hth
-->Slow
Re: Heated O2 Sensor in Modified Exhaust Write Up
Tuesday, March 20, 2007 10:50 AM
So is this mod for any after market exhaust? and someone said "it stops the stalling" by that do you mean when you step the clutch in at a stop sign the rpms drop and it sounds like the car is going to die?

Re: Heated O2 Sensor in Modified Exhaust Write Up
Tuesday, March 20, 2007 12:39 PM
Kevin wrote:

So is this mod for any after market exhaust? and someone said "it stops the stalling" by that do you mean when you step the clutch in at a stop sign the rpms drop and it sounds like the car is going to die?


This is not a fix you that problem you speak of.



FU Tuning



Re: Heated O2 Sensor in Modified Exhaust Write Up
Tuesday, March 20, 2007 1:02 PM
Do all O2 sensors give the same signal, or voltage output, so that the computer understands it, or do they vary? I am thinking about buying the Universal Bosch 4-wire O2 Sensor Part # 15729 for my Cav, but I have the 1 wire setup. I want to make sure that it will work before I go hacking up harnesses and wires, and such. I would buy the retrofit kit I mentioned before in this thread, but all it looks like is a sensor, with a custom harness made for easy plug and play. I don't mind wiring it myself, especially if it will save me $40.



2010 Subaru Impreza WRX Limited
1999 Cavalier Z24 Supercharged
1999 Grand AM SE (Beater Car)
1997 GMC Sierra
2007 Honda CBR 600RR
2005 Honda TRX450R
Re: Heated O2 Sensor in Modified Exhaust Write Up
Tuesday, March 20, 2007 4:47 PM
Maybe not this thread, but I vote a write up with pictures makes a sticky...just a thought.
Re: Heated O2 Sensor in Modified Exhaust Write Up
Saturday, March 24, 2007 2:58 PM
Well what do you do if you have a turbo motor and want to run wideband O2 for the best tuning, does anyone make a heated wideband O2?


2000 Z24 5spd header & catback for now.
Re: Heated O2 Sensor in Modified Exhaust Write Up
Saturday, March 24, 2007 6:31 PM
Luke Heier wrote:

Yeah, I'm having that problem with my Cav. I would like to do this also, but I have a 1 wire O2 sensor. I found a retrofit kit from Caspers Electronics here: Kit

Anyone know exactly how it works? I'd rather save myself some money and make my own...Just need to know which wires go where.



I've been running this kit for a year now. I like it, easy installation, and no more cold start issues!



Car is for Sale!Supercharger kit is for sale!
Re: Heated O2 Sensor in Modified Exhaust Write Up
Sunday, March 25, 2007 5:04 PM
I am going to do this tomorrow or the next day, depends if its in stock when I go tomorrow and I just have one question.

Quote:

Now you must attach both of the white wires from the new sensor to the 2 brown wires.


Does it matter which white wire goes to which brown wire? Am I correct in assuming you soldered all the connections you made? Or did you connect them some other way?


Quote:

(I chose not to tap into the wires on the sensor side of the plug because it is a $170 sensor from GM)

Wouldn't replacing the harness be more expensive? It looks easier to do the harness side anyway, the wires are right there.

Sorry for all the detail questions. I just like to know all I can about something before I get into it.

Shawn M.

PSN ID: Phatchance249

Re: Heated O2 Sensor in Modified Exhaust Write Up
Sunday, March 25, 2007 9:10 PM
okay i think this is exactly what is going on with my setup. I noticed it right after i upgraded to my full 2.5" and changed the sensors to bosch ones. The car will usually die when i put in the clutch especially if i don't even get to shift out of first and have to stop its almost a guarantee. I read in another post they said theres stopped when they switched back to ac delco sensors. How far away do you guys have your o2 sensor mounted from the turbo outlet downpipe flange? Sweet. I can't wait to get this issue figured out it really irritates me. lol.


~Boost. Its what's for dinner!~

Re: Heated O2 Sensor in Modified Exhaust Write Up
Monday, March 26, 2007 1:02 AM
Shawn McKenzie wrote:

I am going to do this tomorrow or the next day, depends if its in stock when I go tomorrow and I just have one question.

Quote:

Now you must attach both of the white wires from the new sensor to the 2 brown wires.


Does it matter which white wire goes to which brown wire? Am I correct in assuming you soldered all the connections you made? Or did you connect them some other way?

I t does not matter as long as both the white wires are connected to both brown wires. I stripped about 1/4" of the insulation off of the brown wires without cutting the wire, poked an awl through the wire to make a hole then strip about 1/2" of the ends of the white wires and thread it through the hole like threading a needle, then wrap it around until there is no more wire left, then solder the joints, brush on some liquid electrical tape and wrap with regular electrical tape.

Quote:

(I chose not to tap into the wires on the sensor side of the plug because it is a $170 sensor from GM)

Wouldn't replacing the harness be more expensive? It looks easier to do the harness side anyway, the wires are right there.

I find that the wires on the harness are easier to strip and work with than the wires on the O2.

Sorry for all the detail questions. I just like to know all I can about something before I get into it.

Shawn M.



I have my o2 sensor about 6" from the turbo outlet, just because its easier to get to.






Re: Heated O2 Sensor in Modified Exhaust Write Up
Monday, March 26, 2007 5:39 AM
Dale Young wrote:

Well what do you do if you have a turbo motor and want to run wideband O2 for the best tuning, does anyone make a heated wideband O2?


I know the AEM UEGO O2 sensor is heated, I'm not sure about others but I'd imagine its a common trend in the market.
Re: Heated O2 Sensor in Modified Exhaust Write Up
Monday, March 26, 2007 1:49 PM
So the reason for this problem is the downstream o2 not reaching the appropriate operating temperature? If this is the case wouldn't an o2 simulator fix the problem? I will probably end up doing the bosch 4 wire mod and pray that it stops the problem. I will measure how far my primary o2 is away from the turbo later tonight.


~Boost. Its what's for dinner!~


Re: Heated O2 Sensor in Modified Exhaust Write Up
Monday, March 26, 2007 2:32 PM
This is for the 1st O2 sensor, the one at the collection point on the header. The down stream one after the cat is already 4 wire.

I bought mine today but I have to wait for the car to cool down. Kinda ironic, the CEL of the O2 sensor went off today as I was driving around. Now I am a little hesitant to go through with this.

PSN ID: Phatchance249

Re: Heated O2 Sensor in Modified Exhaust Write Up
Monday, March 26, 2007 7:10 PM
You can't put an O2 simulator on the pre cat sensor it makes the fuel corrections. the post O2 sensor can be simulated....I've got the post simulated and it works great.
Re: Heated O2 Sensor in Modified Exhaust Write Up
Tuesday, March 27, 2007 8:54 AM
So you would be using the first o2 to be read for the heat for the second o2 since the second one isn't get up to temperature? Would somebody mind making a diagram in like paint for me. I think I am going to attempt this today but I am more visual. From what I have gathered you hook up the black and gray to its original sensor location with the plug and then take the two white wires and attach one each to the two brown wires from the second o2 senosr? This will be the white wires if I have already got a bosch sensor installed for the second o2 right. Sorry for all the questions I just want to make sure I understand what this mod is doing and how before I do it. Thanks all and great write up. I am almost thinking STICKY!


~Boost. Its what's for dinner!~

Re: Heated O2 Sensor in Modified Exhaust Write Up
Tuesday, March 27, 2007 9:56 AM
Here is my attempt to explain it, not sure if I understand what your saying.

The first o2 is what this is fixing. That sensor doesn't get up to temp in the new locations b/c of headers or a turbo conversion or whatever.
You buy a self heating (4 wire) universal o2 sensor.
Take out the first o2 on your car.
Cut the sensor off with enough wire left so it reaches the harness plug.
Attach the two wires that you just cut to the corrisponding two wires on the new plug.
Then find where the second (rear) o2 sensor connects to the engine harness.
There should be two wires that are colored the same, tan / brown.
Connect the two remaining wires, should be same color, on your new sensor with the tan / brown wires on the harness right after the plug for the second o2.

All of this was on the instructions that came with my sensor. Its pretty strait forward. You don't really have to connect into the second o2, just an ignition power source and a ground.

PSN ID: Phatchance249

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