Exhaust ground wire? [Merged 3-7] strap copper braid

[InFlames]

I just installed my full 3", when i was removing the old pipes, i unbolted a ground wire that was hooked to the DP (i think). Is this ground wire imoprtant? Where can i hook it back up to, there is no clamp on the new exhaust?

 

[ricktsu]

o2 sensor?

 

[GoFastTSI]

Yes, reclamp it to your new DP. That's the O2 grounding strap and without it, you'll be running overly rich.

 

[GrocMax]

What happens in many cases with the DP ground strap removed, is the O2 sensor will never reach full voltage. Ground loop goes gizzy.
In other words, it will hit a maximum of say .84-.86v (1G) and you will get a false fuel trim correction to rich because it reads lower than it should.
Also trying to 'toon' it via factory O2 sensor output becomes an exercise in futility.
Some cars will not be affected by strap removal, some will.

 

[90GSX]

I never noticed a difference without the grounding strap. Correct me if I'm wrong, but at WOT (my preferable mode of driving) the ECU goes into open loop and ignores the O2 sensor, relying on a 2D fuel map based on airflow and RPM, so WOT tuning shouldn't change. However off idle and part throttle tuning may be "an exercise in futility" as you say, since the ECU is in closed loop and will rely on several sensors, including the O2, to provide fuel enrichment, ignition timing, etc...

Where is Todd Day when we need him???

 

[InFlames]

AHHHHH, thanks dudes!

 

[NDgsx]

Originally posted by 90GSX
but at WOT (my preferable mode of driving) the ECU goes into open loop and ignores the O2 sensor, relying on a 2D fuel map based on airflow and RPM, so WOT tuning shouldn't change.

So you have no fuel control or datalogger? The stock ecu does everything and the car runs perfect? A lot of people shoot for an o2 voltage when tuning, like .90. It's not very accurate, but still a lot of people do it.

 

[90GSX]

Originally posted by NDgsx


So you have no fuel control or datalogger? The stock ecu does everything and the car runs perfect? A lot of people shoot for an o2 voltage when tuning, like .90. It's not very accurate, but still a lot of people do it.

I have a VPC and a Datalogger...

I should have been more specific. I don't believe that ECU changes it's fuel enrichment curve based on O2 sensor voltage at WOT, because it's in open loop, ignoring everyhting except airflow, engine RPM and the corresponding pre-programmed 2D maps. Does that make more sense? I may still be wrong, at least that's the understanding I have from reading years of Talon Digests...

I usually ignore the O2 sensor at the track, b/c the leaded race gas seems to dull the O2 sensor, and make it respond slowly. I usually see O2 voltages around .7-.8.

At the track, I tune by the knock sensor and timing... i.e. no knock and lots of timing means I turn the boost up and fuel down, until I get a touch of knock without the ECU retarding timing. I don't know if this is the best way to tune it, but it seems to be the best way to find "the ragged edge", on which my car seems to enjoy running.

 

[NDgsx]

Eric, I understand what you are saying and yes you ARE right. You just misunderstood what Scott was saying. A LOT of people still tune off of 02 voltage for some reason (even though a 4 wire o2 sensor is nowhere near accurate for measuring a/f in the 11:1-13:1 range).
The different specific gravity of race fuel is what changes your o2 readings, not the lead. The lead will make the sensor slower to respond though.
I only tune by knock normally, you can knock from being too rich though also, so in times like that the o2 voltage can come in handy.

 

[drewstealth94]

I just installed my exaust system about a week ago and rememberd i had to ask this question. There was this little braided metal line attached to the bottom of the car to my exaust pipeing. It looked just like a ground or something but i'm not sure. Right now it isn't connected to anything it just hangs from the bottom of my car. I haven't noticed any problems but just wondering what it is for and if i can remove it. Thanks

 

[LethalEagle]

Hey drewstealth94...
That is supposed to be a ground for the O2 sensor. You should try to remount it onto your new exhaust. Some O2's require the ground, to work properly.

 

[ginsu417]

It's just a grounding strap to keep everything grounded. I cut my ground strap off when I did my exhaust and have seen no ill effects.

 

[twenty5psi]

whoa..maybe youd want to hook that back up to something metal because it was put there for a proven reason by mitsubishi..or is it just me but that has to be there for some reasoning of grounding something even if it is just extra id still hook it back to like the frame of the car or whatever..just my 10 cents..sorry couldnt find any penies ..later
chris

 

[ginsu417]

It actually connects to the heat sheild around the exhaust if I remember correctly. It's just there to absorb any electrostatic charge present in that part of the exhaust system. It doesn't really do anything useful, and I kind of wonder why they bothered to put it there.

 

[doug]

Many people (probably 2G only, but I don't know) report getting crappy gas mileage until they hooked the ground strap back up. Affects the rear O2 sensor readings somehow, I think.

 

[ginsu417]

Yeah, 2Gs have a 2nd O2 sensor. Forgot about that. 1Gs don't appear to use that wire for anything though, since the O2 sensor is on the manifold. If someone knows any reason this needs to be hooked up on a 1G, please let us know
- K

 

[drewstealth94]

Well i haven't noticed any type of problems that could be related to that. Only thing i noticed since installing my exaust is if i drive my car and turn it off and a second later turn it back on i here like sort of a bang noise from under the car. I think it is just because there is a little exaust fumes left in the car becuase of the less backpressure of the 3inch pipeing and so if you turn the car on it is all released really fast and it makes the noise but i don't know. Becuase if i let the car sit for like 10 minutes it doesn't happen. Also i here a howling noise comeing from somewhere when i hit around 7 psi and above. But that is on my stock gauge and it is not accurate.

 

[Smoothie97]

I just installed an Apexi N1 and Apexi downpipe. After taking off the stock exhaust, I noticed there was a short, black grounding wire that was bolted to the stock piping. After I installed the N1, I couldn't find a place to ground this wire so I just left it dangling right now.

Was this wire grounding my O2 sensor in the exhaust? I notice that I do get A LOT of white smoke now. BTW, no check engine light yet with the install.

 

[canzures]

I would also like to know the answer to this one since you and I are in the same predicament.

 

[Coldandafraid]

Type in "Ground strap" in the search, you will get plenty of reading material:

http://www.dsmtuners.com/forums/showthread.php?s=&threadid=34954&highlight=ground+strap

 

[ROOKIE1]

what is the point of this ? just got rnr exhaust , has no ground connection. also what kind of clamps do i need to install this turbo back ? did not come with any .

 

[K Dan]

what do you mean exhaust ground? an exhaust system is just metal pipes, no electrical equipment . Just go to you local auto parts store and get some 2.5" or 3" clamps depending on what size you got for however many you need.

 

[Defiant]

It's either to do with the O2 sensor, or -more bizarre- somehow, someway relates to the _stereo_ system. It's part of the overall chassis grounding, and there are thousands and thousands of cars running without them.

 

[ROOKIE1]

do grounding kits serve any real purpose ? or are the mainly for looks ?

 

[bigjangin]

just stick on one of the hangars, its what I did. Some people run without them, but why risk a problem in the future? Its not hard to do, just wrap it around one of the hangars and make sure its secure.