O2 Sensor Wiring

[32valvZ]

Tried on the other forum... no replies... Anyone know if this is ok?
Thanks, John

I will need to lengthen my O2 sensors wiring harness due to adding headers. I have some old O2 sensors. Can I just cut the wires from the old ones and solder them together to get the length I need. Obviously, the wire gauge is the same, so the voltage through them should be consistent. Is this ok to do?

[Jagdpanzer]

I switched to NTK 21003 which have longer pigtails than stock O2 sensors and work great. $28.89 at Rockauto

[32valvZ]

I switched to NTK 21003 which have longer pigtails than stock O2 sensors and work great. $28.89 at Rockauto

So I would guess lengthening them on my own would be ok...

[Hib Halverson]

I wouldn't splice O2S harnesses. This from the Corvette Service Manual:

The heated oxygen sensor uses a permanently attached pigtail and connector. This pigtail should not be removed from the oxygen sensor. Damage or removal of the pigtail or connector could affect proper operation of the heated oxygen sensor.

From a GM service information source other than the Corvette FSM:

Do not repair the wiring, the connector or the terminals. Replace the oxygen sensor if the pigtail wiring, the terminals or the connector is damaged. Proper oxygen sensor operation requires an external air reference. This external air reference is obtained by way of the oxygen sensor signal and heater wires. Any attempt to repair the wires, the connectors or the terminals results in the obstruction of the air reference and degrades the oxygen sensor performance

Here's your solution:
I switched to NTK 21003 which have longer pigtails than stock O2 sensors and work great. $28.89 at Rockauto

[32valvZ]

Ok, got those ordered... Thanks guys..:cheers:

[Paul Workman]

I wouldn't splice O2S harnesses. This from the Corvette Service Manual:



From a GM service information source other than the Corvette FSM:



Here's your solution:

Well, w/ all due respect to you, Hib, I beg to differ with that particular GM source to the extent of warning against splicing the pigtails disrupting the function of the sensor. :blahblah:

In their defense, when considering the range of potential DIY'er talent, it is safer for the 'official GM documentation' to avoid the entire question of liability by simply recommending nothing be done to any part of the car except (maybe) changing/adding oil.[-X

That said, when it comes to manipulating the sensor and inserting an extension, anyone with the equipment and ability to solder can do it w/o issues. I know first hand what will and what will not cause the O2 to fail: splicing in a section of wire to extend the length WILL NOT impede the sensor AS LONG AS THE SPLICE DOES NOT IMPEDE THE AIR FLOW WHERE THE WIRES ENTER THE SENSOR.

If you cut the wires leaving enough length so that soldering and shrink wrapping (i.e., weatherproofing) leaves the original wires entering the top of the sensor intact, there's NO PROBLEM. But, close off the wire entry with any kind of sealant or grime and then the sensor will fail. FACT!

NOTE: I extended my pigtails to ~ 18-20" long (passenger side) by splicing in a section between the sensor and the Weather Pack (https://www.delcity.net/productsearch?search=Weather+pack+connectors&x=13&y=13&it=) connector, allowing me to relocate the O2 to the side of the SW header collector (for ease of access).

The O2s have been there for 30k+ miles through torrential rains and and snow and survived bottoming out on a muddy hillside. They still work good as the day they were installed. That tiny space between the wires where they enter the O2 sensor is sacred to the O2's survival. If it gets blocked with anything, then the sensor cannot sample the atmosphere (air) which is essential to its operation.

[Jagdpanzer]

Here is a photo of the the NTK
8141


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[Karl]

I have to agree with Paul. I have extended o2 sensors without issues.

Also those NGK sensors are on eBay new for $14 each with free shipping.

[32valvZ]

ok, so there is no possible way that sensor wiring above will even remotely work.... Im looking at 18-20 inches too short on the passenger side. :cry:

[Jagdpanzer]

Bummer, the wiring harness on your car must have be different than on my 94.
Tell you what, the other day while digging through my parts stash I came across this 20” O2 extension I had picked up from Ron Woods many moons ago. You’re welcome to it if it’s what you need.8153


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[32valvZ]

Outstanding... that looks like what I need. Ill double check the distance again in the morning.... just came in from the garage.... kinda tired. Thank you very much for your gracious offer!
:cheers:

[Young1]

I cut the wires off a bad oxygen sensor then got a quick pack on eBay and installed it. I put the extension on the right-hand side which is a terrible design by GM to simply change the sensor out. Next time won't be a problem.

[32valvZ]

I cut the wires off a bad oxygen sensor then got a quick pack on eBay and installed it. I put the extension on the right-hand side which is a terrible design by GM to simply change the sensor out. Next time won't be a problem.

I gave that a thought... I actually cut the wires from a bad one and mocked it up.... still about 10-12" short... The connection behind the motor mount is just stupid!! If I could get that un-done from behind there, I might get some length out of it....

[Young1]

Yes it is stupid. That was pre-assembled before they drop the motor in on the assembly line. Just take out that 45° angle brace and some other pieces in there and you can get to it more easily. Without some disassembly it's impossible to get that thing unlatched. I have stock manifolds by the way.


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[32valvZ]

Bummer, the wiring harness on your car must have be different than on my 94.
Tell you what, the other day while digging through my parts stash I came across this 20” O2 extension I had picked up from Ron Woods many moons ago. You’re welcome to it if it’s what you need.8153


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Ok, remeasured... That would work fine. Ill PM you.
Thanks again!:cheers:

[32valvZ]

So I got both the left and right side headers installed today and of the 32 bolts, I got 29 in. I used a combination of the factory bolts and shorter allen head bolts I had from many years ago when doing the headers on my 92 Z. Pays to be a pack rat sometimes....:o

[32valvZ]

More Pics
On the last one, not really sure how to decipher the numbers on the block, or what they mean....

[WARP TEN]

More Pics
On the last one, not really sure how to decipher the numbers on the block, or what they mean....

The number your photographed is 10ZSH X00625 0006.

The 10ZSH is a Mercury Marine tracking number for a 1990 engine with A/C. The X0 idesignates the build year 1990. The 062 is the month and day, June 25. The 0006 shows it is the 6th build of the day. The car serial number is found in another spot, on a block at the back of the block on the passenger side up near the valve cover. It will show something like this: 1S5 800409 (from a 95 #409) along with some other numbers. The "800409" is the car's serial number. OK I cheated--It's all on the ZR-1 Net Registry home site under "Information/General/VIN Numbers". --Bob

[32valvZ]

Awesome...thanks Bob!

[WARP TEN]

Here are a couple of pics showing where the VIN shows up on the engine. It is on the vertical block just behind the rear cylinder in the engine picture. The numbers in the other picture are a bit hard to read but it shows #409's proper engine number. Of course it is quite easy to read these numbers when the block is out of the car! --Bob

[32valvZ]

After much wrestling with the o2 sensor jumper I got from Phil... I finally got it in... man this sucked.... wound up getting it clipped together with the harness through the front of the engine cradle... came loose from the keeper.. Then had to get a wire hangar fish it through and pull it back to the rear of the engine... Sure was hard squeezing my arm down between the upped rad hose and AC pressure line... Good grief... well, using a tapped boss on the side of the engine and a stud that used to keep the heat shield for the cat, its all up and in place...Thats enough for one night for this ole man...

Thanks again Phil.

[32valvZ]

Got the headers done and everything wrapped up for now. Put it together without the cats.... Ill need to bring them to an exhaust shop along with a new X pipe to get welded up proper. Sounds really good and I can feel an increase in torque and better throttle response. I have a total of around $850. in it before getting a new X pipe and taking it to the shop to weld it up.

I appreciate everyone's help and suggestions.

[Hib Halverson]

Well, w/ all due respect to you, Hib, I beg to differ with that particular GM source to the extent of warning against splicing the pigtails disrupting the function of the sensor. :blahblah:

In their defense, when considering the range of potential DIY'er talent, it is safer for the 'official GM documentation' to avoid the entire question of liability by simply recommending nothing be done to any part of the car except (maybe) changing/adding oil.[-X

That said, when it comes to manipulating the sensor and inserting an extension, anyone with the equipment and ability to solder can do it w/o issues. I know first hand what will and what will not cause the O2 to fail: splicing in a section of wire to extend the length WILL NOT impede the sensor AS LONG AS THE SPLICE DOES NOT IMPEDE THE AIR FLOW WHERE THE WIRES ENTER THE SENSOR.

If you cut the wires leaving enough length so that soldering and shrink wrapping (i.e., weatherproofing) leaves the original wires entering the top of the sensor intact, there's NO PROBLEM. But, close off the wire entry with any kind of sealant or grime and then the sensor will fail. FACT!
NOTE: I extended my pigtails to ~ 18-20" long (passenger side) by splicing in a section between the sensor and the Weather Pack (https://www.delcity.net/productsearch?search=Weather+pack+connectors&x=13&y=13&it=) connector, allowing me to relocate the O2 to the side of the SW header collector (for ease of access).

The O2s have been there for 30k+ miles through torrential rains and and snow and survived bottoming out on a muddy hillside. They still work good as the day they were installed. That tiny space between the wires where they enter the O2 sensor is sacred to the O2's survival. If it gets blocked with anything, then the sensor cannot sample the atmosphere (air) which is essential to its operation.

I apologize for posting FSM information. The people at GM who wrote it must have no idea of what DIYs can do in the real world.[-X

Splice away, people.:thumbsup:

[32valvZ]

I apologize for posting FSM information. The people at GM who wrote it must have no idea of what DIYs can do in the real world.[-X

Splice away, people.:thumbsup:

Hey man, take it easy... I believe Paul was just saying he did it and it worked out for him... and a few guys on the other forum have done the same thing with no issues either.

No one doubts the engineers at GM knew/know their stuff... Its just sometimes the factory doesnt want anything messed with by Joe Public... ESPECIALLY where federal emissions were/are involved.

That said, I also doubt GM would have figured 30 years later there would be a bunch of guys like us swapping parts off for performance necessitating the need for an O2 sensor wire extension anyway.... :-D

I respect EVERYONE'S opinion here... yours, Pauls and all the other members.... No one should take offense to anothers opinions or experiences...:cheers:

For what its worth, I didnt splice it, I used an extension harness and it seems to be ok so far anyway.... :)