O2 Sensor Tuning - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Mertz · 11-10-2009, 12:04 PM

I installed a wideband (Standard SG-12) O2 sensor in my header to try to tune in my Q-jet. It warmed up fine but when I went for a drive it went to negative volts. It started out at -50mv then went up to -140mv at cruise after some more driving. If I put it under load it would go to 770mv and then drop back down to -140mv. Warmed up and in park in the driveway after the trip it went to 820mv and gradually dropped. I didn't waight to see how far it would drop. I rev'd it a little and it goes down to almost zero and climbs back up to 820 before dropping again.

The exhaust is good with no leaks. I have not been able to find a vacuum leak but I think that might be causing the problem. Anybody had this same experience?

Shon · 11-10-2009, 02:22 PM

This is a 5 wire Wideband O2?
what is being used to monitor the readings?
Was it calibrated?

PowerPro · 11-10-2009, 02:59 PM

not sure about the voltage reading at all. The last time i did that sort of tuning was on an Rx-7 and we just got an autometer guage and tuned it to green / a little orange (slightly rich is better than lean)

Ackattack · 11-10-2009, 03:37 PM

I have an LC-1 or LM-1, and I remember when I was installing it in my Corvette I read a lot of people having issues due to bad grounds.....that's what I'd check.

Mertz · 11-10-2009, 03:41 PM

It could be a ground. It seemed to work where ever I put it but it was never very substantial. The O2 sensor is a one wire non heated unit I got based on info on the net.

The correct leads are going to the O2. The positive red on the multimeter to the O2 and the black negative to the ground. It does register positive when it is rich.

Shon · 11-10-2009, 03:40 PM

X2 on the grounds but the negative numbers is what is odd, unless it is not set up right.

Shon · 11-10-2009, 03:44 PM

1 wire is not going to be a good tuning tool and is not a wideband.
that O2 sensor is only accurate at stoich (14.7ish) and that millivolt reading is right at .451
you need a good wideband.
I have used Innovate and now using AEM. The innovate is good but grounds are an issue. and I was trying to get something to use in a variety of vehicles so I went with the AEM unit ($225 shipped) and it's much easier to deal with.

Mertz · 11-10-2009, 04:42 PM

It is my understanding that this is a wideband sensor. It only has one wire because it is not heated. I get voltage readings from -140mv to 1100mv.

Shon · 11-10-2009, 04:51 PM

you have a narrowband O2.

http://www.widebando2sensor.com/pages/Wideband-o2-FAQ

Mertz · 11-10-2009, 11:57 PM

This actually a Bosch 11027 that they gave me when I asked for a SG-12. Are all one wire O2 sensors narrowband? What would be the cheapest wideband I can get to make this work?

Jim_PA · 11-11-2009, 01:03 AM

You either want the Bosch 17053 or Bosch 17014

I think the only difference between the 2 is cable length (from my online research anyway...)

Amazon.com: Bosch 17014 Oxygen Sensor, OE Type...

Shon · 11-11-2009, 08:42 AM

Jim is right, you need a different O2 but you also need to have the equipment to read the sensor.
what are you using now???

Mertz · 11-11-2009, 11:56 AM

I am using a multimeter to record voltage from which I can go to my chart and see what the air/fuel ratio is. 450mv is about 14.7:1, 950 mv is about 12.5 and 250mv is about 15.5 and others in between. I figure idle and cruise should be at about 500 with WOT about 12.5.

Shon · 11-11-2009, 12:00 PM

450mv is right, those other numbers are shots in the dark b/c that sensor is only accurate at stoich.

Jim_PA · 11-11-2009, 05:35 PM

Just get one of these:

$125 with a sensor.

http://14point7.com/Widebands/JAW_1_041/JAW_1_041.htm

11-10-2009, 12:04 PM	#1
Mertz Registered User Join Date: Aug 2007 Location: Reardan, WA Posts: 132	O2 Sensor Tuning I installed a wideband (Standard SG-12) O2 sensor in my header to try to tune in my Q-jet. It warmed up fine but when I went for a drive it went to negative volts. It started out at -50mv then went up to -140mv at cruise after some more driving. If I put it under load it would go to 770mv and then drop back down to -140mv. Warmed up and in park in the driveway after the trip it went to 820mv and gradually dropped. I didn't waight to see how far it would drop. I rev'd it a little and it goes down to almost zero and climbs back up to 820 before dropping again. The exhaust is good with no leaks. I have not been able to find a vacuum leak but I think that might be causing the problem. Anybody had this same experience?

11-10-2009, 02:22 PM	#2
Shon Registered User Join Date: Sep 2005 Location: sc Posts: 1,203	Re: O2 Sensor Tuning This is a 5 wire Wideband O2? what is being used to monitor the readings? Was it calibrated? __________________ 71 Cheyenne C10 LWB cam'd 6.0/T56 Swap

11-10-2009, 02:59 PM	#3
PowerPro Registered User Join Date: Sep 2009 Location: Spokane, WA Posts: 68	Re: O2 Sensor Tuning not sure about the voltage reading at all. The last time i did that sort of tuning was on an Rx-7 and we just got an autometer guage and tuned it to green / a little orange (slightly rich is better than lean) __________________ 1970 C20 LWB Fleetside with a 472 Caddy engine! TH400 Restoration in progress 07 Yamaha 650 V-Star Custom 83 Honda V-45 Magna

11-10-2009, 03:37 PM	#4
Ackattack Senior Member Join Date: Aug 2002 Location: Valley Center KS Posts: 3,525	Re: O2 Sensor Tuning I have an LC-1 or LM-1, and I remember when I was installing it in my Corvette I read a lot of people having issues due to bad grounds.....that's what I'd check. __________________ Project Bruiser: 68 Pro-Touring C-10 5.3L / 4L60E Project Ironhide: 97 GMC Crew Cab 4x4 Cummins SOLD: '69 GMC 1/2T SWB TBI'd: Project No Buck Assembly Manual Index Sign up Thread!!! Factory Service Manual Index

11-10-2009, 03:41 PM	#5
Mertz Registered User Join Date: Aug 2007 Location: Reardan, WA Posts: 132	Re: O2 Sensor Tuning It could be a ground. It seemed to work where ever I put it but it was never very substantial. The O2 sensor is a one wire non heated unit I got based on info on the net. The correct leads are going to the O2. The positive red on the multimeter to the O2 and the black negative to the ground. It does register positive when it is rich. Last edited by Mertz; 11-10-2009 at 03:43 PM.

11-10-2009, 03:40 PM	#6
Shon Registered User Join Date: Sep 2005 Location: sc Posts: 1,203	Re: O2 Sensor Tuning X2 on the grounds but the negative numbers is what is odd, unless it is not set up right. __________________ 71 Cheyenne C10 LWB cam'd 6.0/T56 Swap

11-10-2009, 03:44 PM	#7
Shon Registered User Join Date: Sep 2005 Location: sc Posts: 1,203	Re: O2 Sensor Tuning 1 wire is not going to be a good tuning tool and is not a wideband. that O2 sensor is only accurate at stoich (14.7ish) and that millivolt reading is right at .451 you need a good wideband. I have used Innovate and now using AEM. The innovate is good but grounds are an issue. and I was trying to get something to use in a variety of vehicles so I went with the AEM unit ($225 shipped) and it's much easier to deal with. __________________ 71 Cheyenne C10 LWB cam'd 6.0/T56 Swap Last edited by Shon; 11-10-2009 at 03:50 PM.

11-10-2009, 04:42 PM	#8
Mertz Registered User Join Date: Aug 2007 Location: Reardan, WA Posts: 132	Re: O2 Sensor Tuning It is my understanding that this is a wideband sensor. It only has one wire because it is not heated. I get voltage readings from -140mv to 1100mv.

11-10-2009, 04:51 PM	#9
Shon Registered User Join Date: Sep 2005 Location: sc Posts: 1,203	Re: O2 Sensor Tuning you have a narrowband O2. http://www.widebando2sensor.com/pages/Wideband-o2-FAQ __________________ 71 Cheyenne C10 LWB cam'd 6.0/T56 Swap

11-10-2009, 11:57 PM	#10
Mertz Registered User Join Date: Aug 2007 Location: Reardan, WA Posts: 132	Re: O2 Sensor Tuning This actually a Bosch 11027 that they gave me when I asked for a SG-12. Are all one wire O2 sensors narrowband? What would be the cheapest wideband I can get to make this work?

11-11-2009, 01:03 AM	#11
Jim_PA Registered User Join Date: May 2005 Location: PA Posts: 2,696	Re: O2 Sensor Tuning You either want the Bosch 17053 or Bosch 17014 I think the only difference between the 2 is cable length (from my online research anyway...) Amazon.com: Bosch 17014 Oxygen Sensor, OE Type... Last edited by Jim_PA; 11-11-2009 at 01:05 AM.

11-11-2009, 08:42 AM	#12
Shon Registered User Join Date: Sep 2005 Location: sc Posts: 1,203	Re: O2 Sensor Tuning Jim is right, you need a different O2 but you also need to have the equipment to read the sensor. what are you using now??? __________________ 71 Cheyenne C10 LWB cam'd 6.0/T56 Swap

11-11-2009, 11:56 AM	#13
Mertz Registered User Join Date: Aug 2007 Location: Reardan, WA Posts: 132	Re: O2 Sensor Tuning I am using a multimeter to record voltage from which I can go to my chart and see what the air/fuel ratio is. 450mv is about 14.7:1, 950 mv is about 12.5 and 250mv is about 15.5 and others in between. I figure idle and cruise should be at about 500 with WOT about 12.5.

11-11-2009, 12:00 PM	#14
Shon Registered User Join Date: Sep 2005 Location: sc Posts: 1,203	Re: O2 Sensor Tuning 450mv is right, those other numbers are shots in the dark b/c that sensor is only accurate at stoich. __________________ 71 Cheyenne C10 LWB cam'd 6.0/T56 Swap

11-11-2009, 05:35 PM	#15
Jim_PA Registered User Join Date: May 2005 Location: PA Posts: 2,696	Re: O2 Sensor Tuning Just get one of these: $125 with a sensor. http://14point7.com/Widebands/JAW_1_041/JAW_1_041.htm Last edited by Jim_PA; 11-11-2009 at 05:35 PM.



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