Thread: Regrounding the O2 Sensor

Alright so let me get this straight? A bad ground location can ruin a good ground?

I will be testing with both and will see how it goes.



I would suggest that too, since my tests will not be as detailed as yours. The only thing I will be able to see is if my gas mileage goes from 19MPG City Only with under 4k shifting to anything better.

Where are you getting your sensor from? I can send you an email of the guy to contact for the eBay one for $30 shipped if you wish. I will make that info public after it is confirmed that everything works.


Alright here is something interesting...

My Rear O2 sensor broke last time I had my catback off. So today I tried to unscrew the O2 sensor again, no avail but look at what I found!



Now I knew it was a four wire so thats nothing big, but it gets interesting.



The wires you see showing there is, White x2 and Black. Now where did our dear ground go?!?!



Oh look at that, thats our great ground wire.

Now I'm not sure what the part number is on that O2 sensor, but I do know that Part # 15727, would fit on the Cat as a Universal After Cat Replacement O2.

Interesting!

So where does that lead us? Maybe a ground connection can be achieved with a 3 wire O2 sensor!

No, Im not saying a bad ground location can ruin a good ground. But I am saying and have always said: that the grounds for the ECU, MAF and O2 sensor should be at the exactly same location as this will guarantee a common ground with 0 differences to evaluate the performance differences. This way we will know the exact effects of the mod without deviations. Im not doing all of this for fun... Im trying to improve performance. You have it wrong as for my testing would be more detail. Its accuracy of improvements that Im trying to ascertain.. I have tested that location, stated the lower grounding quality difference, and have explained why its a bad location. But, you keep returning to using that location and I cant understand why. I know the results will be impacted by using that location and will deviate the expected results and possibly give worse results. So if you use that location, your results cannot be validated. But thats okay. Im sure that we will have this discussion again when the mod performance improvements are compared. We may find once we are done, that this mod will give absolutely no improvements. But we can only determine that if we have a basis for comparitive purposes. I need to have a known base measurements to validate the test results. You just wont be able to provide those measurements due to your planned setup.

I will probably just buy a universal one locally... I will check around and find one a a decent price. Using one from the junkyard isnt a good idea either due to the unknown condition of the sensor. I just purchased a OEM O2 sensor for $100 a few weekends ago. So, thats why I wasnt planning on buying another one until we could prove the level of improvements. But its just money right??

As for your rear O2 sensor, its probably a different part number since its the rear one. I expected that the ground was attached between the body and the thread portion of the sensor. I determined that from the O2 sensor testing last week. But how is it attached... Your picture dont really show that.. I assumed it was simply wedged between the two casings. Is that true??

I understand, but it does seem like a little waste, I am scratching the idea of having the 4-wire connector, don't quite have time for it and etc. The O2 sensor that I just bought has 18 gauge wire on it, the coating is similar to my 18 gauge wire.

Now Stock O2 sensor wire is like 22 gauge, but darn tough to cut through!

What I'm doing is, Im running a 18 gauge wire to a connector that will then get to a 12 gauge wire and then go 12 gauge to the ECU ground.

Here is what I will do, I will run the maf ground and the O2 sensor ground to the left ECU ground:







Oh that sucks man. $100 is a lot, can you return it?

It is just money, but its the money you pay for gas, and isn't this part of the reason we are trying to improve on that?



It was welded on to the casing, so it was pretty sturdy and not movable. I'm assuming most of them will be like this too though.

Here are some more pics of the progress:

Universal 3 wire and Universal 4 wire side by side.



Let it all begin:



18 Gauge Ground wire attached:


The 3 original wires that go to the connector


And the final product


As you see the Ground wire is longer, this is so that I have plenty of wire to work with to make a connector etc.

V -

I would be extra careful, in using common crimp connectors. I used the same style connector, and the o2 sensor didn't register properly. I ended up having to buy a longer Z32TT o2 sensor. Your BEST BET, is to solder/heatshrink the wires.

My o2 sensor wouldn't read below .7 volts, and would hit above 1.2 volts, causing my ultra lean/die issue. The ECU would assume that I was running rich, and continue to lean out the mixture until the car would simply die.

Thanks for the heads up Tek!

Wow thats pretty crazy, basically it would just flood then engine right?

These crimp connections came with this O2 sensor. The package was sealed, so I think the eBay seller buys them with those crimp connections.

I've used the exactly the same Crimp connections on my previous O2 sensor and it worked out fine. I will double check to make sure the wires are properly crimped though

Thats fine.. Running the grounding wire straight back to the Intake Mani will work too.

The new O2 is already installed and non-returnable at this point. So, Im just spending the money for this test.

Yep, we need to get our cars as gas effiencent as possible with $4+ gas prices coming soon. But the Gas mileage improvements and low idle improvements is being accomplished by improving the signal strength with the grounding improvements. If the signal strength remains the same or gets worse, then any hope of these improvements are dismal..

I can't possibly imagine it getting worse, but I guess we'll see.

Hold off on spending money on a sensor for now. I will do mine like you want it, and if I see any MPG upgrades then get one

Now how many miles should I drive on this setup before I start measuring the MPG's?

Is it around 200 miles that the ECU starts to really take advantage of the settings?

Or I could do what I've done with my spark plugs. Since I was running a shorter test, I would install the spark plugs, Reset ECU, drive 50 miles, then jot down the data.

FYI I keep all of my fuel ups in a spread sheet. So everything dating to last year has been tracked. A long with mods at the time of the fuel up and driving styles.

Yes. The MPG testing can begin immediately. You probably wont see any differences until the 2nd or 3rd tank of gas.. But, it could be sooner.. The Regrounded MAF mod is immediate.

I also keep a log of my gas usage and MPG. It usually has hiccups during the Summer/Winter fuel mixture swapouts.

Yes after installing the new O2 sensor, reset the ECU and clear the relearning (unplugging & replugging the TPS while car running).

Im also testing the differences O2 signals at lower RPMs seen by the ECU. Which Im hoping will improve the idle! (probably wont happen but I can wish).

No, the car wouldn't flood. The o2 sensor registers a RICH condition, at over .5~.6V, so the ECU attempts to lean out the mixture. If the ECU keeps receiving a RICH signal, it continues to lean the mixture, until the car doesn't receive enough fuel and just dies. My wideband readings were above 18:1 at idle! It felt like the car was only running on two cylinders, and even pushing on the throttle wouldn't correct the issue.

Anyhow, I still highly recommend you solder the connection. Don't just crimp it.