2 Da Max

iTrader: (2)

well i was just curious what that metal wire on the cat bolt was, is it for a ground for the o2 sensor?

the reason im asking is because that dam bolt came loose, and i have a crazy leak which i cant fix at the moment. the thing is that wire is disconnected. is it necessary? or what?

lilaclucymaxima

iTrader: (16)

It's a ground... it's not a big deal though. Mine's been out for a long time.

dgeesaman

iTrader: (10)

I think it's necessary.

If the bolt hole is ruined and there's no good place to reconnect it, just get a band clamp and clamp the loose end hard to the pipe.

Dave

Black Maxima

I want to know what it's actually used for. When I redid my exhaust system I included a new grounding strap with it too.

lilaclucymaxima

iTrader: (16)

Pictures? Is it more like a shoe lace than an actual wire?

Black Maxima

Braided metal, I guess you could call it a shoelace looking thing.

dgeesaman

iTrader: (10)

It's part of the circuit. The body of the oxygen sensor is the reference used for the signal voltage. Since the exhaust system is hanging by rubber hangers (insulators), the only place it can get back to ground it via the studs going into the manifold. So a direct grounding strap would keep the whole y-pipe assembly at the same exact ground as the ECU.

Dave

2 Da Max

iTrader: (2)

so i could burn up my o2 sensors??

dgeesaman

iTrader: (10)

No, they won't burn up. The signal might be off, is all. Of course, if the signal is off, it could affect fuel economy while cruising.

Dave

Zeus97MAX

I had no idea what that was, when I had to replace my y pipe and cat converter. Mine was so corroded, I couldn't tell what it was, other than a couple thin pieces of corroded *** wire. I have replaced my O2 sensors, but never replaced that ground wire, and still get around 350 gallons to a tank on avg. I don't think your gas mileage will be affected, if any, without the wire.

nismology

iTrader: (8)

It won't. My mileage is fine and those straps are LOOONNGG gone.

2 Da Max

iTrader: (2)

once it doesnt burn up my o2 sensor in happy

btw is ok if i bolt it to the chasis?

dgeesaman

iTrader: (10)

That's not a measurement of gas mileage. That's a measurement of how low you let your tank get before filling, if it measures anything at all.

As for those running without a ground strap, that's fine too. There will only be a single ground path to ground the sensor, which is fine if that path remains low resistance. The risk (recall I performed a resistance test on mine and found it was not good), is the O2 sensor signal will be off, which could affect the fuel economy. If your existing studs and exhaust haven't rusted the way mine have (I drive a LOT of salty highway miles in winter), and your properly calculated fuel economy is still good, it's entirely reasonable that the strap will always be redundant. YMMV.

I replaced my broken ground strap just last night, so in a couple days I will report if it made any impact on fuel economy. For the few bucks that it costs, you can't argue against the value as cheap insurance.

Dave

maxspeed96CT

iTrader: (9)

wow i never knew what this was for either, i gotta atach mine back on....

Jepht20

iTrader: (10)

i've had mine unattached for 2+ years and there was never any change whatsoever in gas mileage or performance...

MrEous

iTrader: (11)

Incorrect...if you fill up the tank to its fullest, then fill up again when you need gas then you can convert to MPG. You have to use your trip odometer, I figured everyone did this already.

Example:
Gas is at close to empty since last fill-up...fill up with 16 gallons and notice the trip odometer shows 350 miles from last fill-up. Then 350/16 would equal ~21mpg.

dgeesaman

iTrader: (10)

That is the proper way to do it. My past experience here suggests that many simply look at how many miles they get per tank and divide the number of gallons the tank can hold, rather than the gallons used to fill up. Many discussions here are based on simply how many miles are on the odo when they fill up, which we both know is crude at best.

Dave

twiggy144

The O2 sensor connector has 4 wires. One of these wires is a chassis ground. So, the O2 sensor is grounded by it's connector. This explains why the braided ground wire if disconnected does not affect anything else. The other the wires of the sensor are: one signal wire , and 2 wires for the heating element within the O2 sensor.

If the O2 sensor was not grounded, the CEL would immediately lit.

newton

hello .. im new to the site plus dont know much about cars .. i have 98 nissan mexima ...recently having a problem which is when i press the gas paddel the ramp gose over 2.8 but the car doesnt seem like picking up the speed like the way im pressing the gas paddel ..its seem like going and then give a kinck and bhom runs allright. its seem like someone puling me from back and then letting it go ..its even bivrate with wired noise +its even give more worse noise + bivrate on reverse gear ..my questions is why its doesnt pick up smoothly? or why the car doesnt run to the minimum speed? what could be the problem and what is the sloution? thanks guys

nismology

iTrader: (8)

What in the world are you talking about? My o2 sensors definitely had only 3 wires. Ditto about 5 of my friends. There are no ground wires.

lilaclucymaxima

iTrader: (16)

mexima? paddel? bhom? bivrate? WTF are you talking about? Go read the stickie and faq's and learn how to talk right before you ***** somebody elses thread with such ridiculous crap.

blackmaxx96

iTrader: (23)

Dude....
I need to put mine back on.. That better not be the reason why BOTH of my main O2 sensors are bad.......

mtrai760

iTrader: (19)

do not hijack peoples threads. Your question is not related to the original topic, therefore you need to start your own thread to get a response to your issue.

dgeesaman

iTrader: (10)

The front O2 sensors are 3 wire. The rear (downstream) are 4 wire. Ref FSM EC-141

In any case, like I said the grounding issue is a theory.

Dave

nismology

iTrader: (8)

I think you shoulda said it was a theory at the beginning of the thread. Now your posts are gonna be "gospel" to n00bs here who are gonna think the motor's gonna blow up without a ground strap. Truth be told, they're unnecessary.

2 Da Max

iTrader: (2)

.... your right about the cel not going off.. i guess its one of those things the world may never know

dgeesaman

iTrader: (10)

Your reading comprehension needs work. I never said their motor or sensors would blow up, I have no idea where that came from, and I refuted it.

I quote myself:
If that reads to you like "gospel", then arguing would be a waste of time.

And as for it being unnecessary, that's a silly statement. There is no way to inspect the connection from the y-pipe to the chassis ground without a resistance meter. A grounding strap is generally quite reliable with just a visual inspection. So even if it's only a backup, it's a simple and effective backup. In fact, it's easier to just install one the next time you're down there than it is to postulate about it on forums. Or don't, frankly I don't care.

But I will not ignore some forum nerd accusing me of writing things I did not write. Especially when gaps in reading comprehension, common sense, and practicality are showing from your side.

Dave

nismology

iTrader: (8)

I thought my sarcasm was clear.......guess not. I was just saying that you should have said it was a "theory" alot sooner, cus now it's causing unnecessary doubt.
My god are you thick-headed. I never said it read like "gospel." I was just saying you're raising doubt for no reason as there are many here than have gotten excellent gas mileage without those straps.
You're thinking too hard man. It's not that serious, really.
Now i'm a forum nerd. Wow!! The belittling sure adds to your credibility. Amazing...

Bottom line is this, the ground from the o2's to the heads are sufficient and will ALWAYS be sufficient. I don't quite understand how a rusted exhaust would affect the ground since the crucial area between the y-pipe and exhaust manifold isn't exposed to the elements anyway. Think about that...

dgeesaman

iTrader: (10)

Sorry bout that. I didn't see your sarcasm. Some people on this forum (and others) say such stupid stuff, so often, that I don't expect it. And I got pretty cranked up about it.

Mine's really rusted; I think road spray has tends to get on those parts, and since they run very hot it accelerates the corrosion process. My y-pipe has also been removed for work, which might contribute to the lack of conductivity over the interface now. Whatever the reason, my multimeter indicated the strap restored continuity of the ground path. And I know from past experience that bad grounding is a tough problem to deal with - it's not so important to have big, thick expensive ground cables everywhere as it is to maintain stock grounding connections.

FWIW, I filled up my gas tank today and so far my gas mileage is unchanged. So even though my sensors went from poorly grounded to well grounded, it did not affect fuel economy.

Dave

nismology

iTrader: (8)

With such a small voltage output coming from the o2's (1V) a good ground is crucial so if the mileage is unchanged the grounding was sufficient all along. I'd be more concerned about this if i had a WB02 with a 0V-5V output. Even then i think it'd be fine.

Ninjamigs1

Grounding and bonding by Mike Holts.
this is a book that all electricians go by.
If there is a ground in a specific location and doesnt make sense to the regular joe. Then best believe JOE that it's there for a real reason. Grounds are established to provide a path for a short/fault to return to its source.(emphasis on source). If it doesn't return to its source then it sits on an "open" circuit". Which means that i charges and energizes the conductor. Or device. Or equipment. Potentially damaging it, getting someone hurt or shocked or w.e....
Either way, even though it doesn't appear to do anything or change anything.
These ground straps actually provided the shortest/alternate route needed for the short/fault to return to its source eliminating the energizing/damaging of w.e.
it needs to be there guys. Lol

But hey i Don't know anything more than most of yall. Have a good day and I hope ya read Mike Holts books.(s)

JvG

The last previous post in this thread is from 2005.

95maxrider

iTrader: (32)

Lol at the 17 year old thread bump for you first post. How in the world did you decide to make this your first post??

For what it's worth, I've always wondered about that strap as well. But I can't imagine Nissan spending money to install them on every car if there wasn't a reason for it. So it was with that in mind that I installed a new one on my car when I was redoing my exhaust, since it probably hasn't had that strap for 15+ years. It cost all of like $1 and took a few minutes.