disconnected ground strap=how much mpg lost?

])rala · Jan 19, 2002

my ground strap is doisconnected i was wondering, what kind of hurt would it cause in gas mileage? 8-10? More or less?

ieatv8s · Jan 20, 2002

zero.

])rala · Jan 20, 2002

Please don't post if you don't know what your talking about
sry for being blunt but if a slightly faulty o2 sensor can knock off 2-4 mpg and if its not grounded right it hurts the reading how can it not hurt a persons mpg?

There are several posts stating that disconnected straps hurt gas mileage.

By the way you have two straps(2nd Gen. 1995+) so perhaps the one you have had disconnected is the 1 that measures how your cat is working and not the 1 that is on the DP(o2 sensor ground). First gens only have 1 ground strap for the DP.

mark93 · Jan 21, 2002

our o2 sensors are a 4wire o2. 2 of the wires are for the internal heating element and the other 2 are(1) is ground reference for the o2 and(2) is for the +voltage. The o2 sensor is not grounded via the casing which means the grounding strap is irrelavant.

ieatv8s wasnt wrong.. he just summed it up in a very easy way!

ieatv8s · Jan 21, 2002

I have had both disconnected and my mileage has not changed one bit.

PS Who looks like an ass now?

])rala · Jan 21, 2002

from looking at the other posts it seems this topic has been somewhat debated by several others. If you review the other posts you'll see why I question your opinion. I meant no offence. I was hoping peeps that have reattached thier ground strap would post thier improvements. I don't feel like an ass, but I must admit I do feel bad that I was so blunt to you...I was outta line being like that. I am not too prideful to apologize, so please accept.

If the strap is on there to improve the o2 sensors voltage reference point then it is a logical question for me to ask I think.

If I am an "ass" atleast I have some company(see following quotes)

90TSI-AWD said:
Ok when I got my 90 talon it had 106k mi. It was totally stock. I drove it about 1 month and averaged 19.8 mpg. I did a complete tune up, including timing belts, 02 sensor, all fluids, spark plugs, wires, timing check and also did the mods you see below. I now averaged about 16.9 miles to the gallon. I even drove it easy to see if my mileage changed. I saw 17mpg taking it easy. So I looked for some answers. to make a long story shorter to found my DP didn't have a ground strap. I put one on it from the DP to 02 housing flange to the frame. Then I put a ground strap from the valve cover to the EX manifold. I got 23.19 MPG on my last tank. Enough said.

danl said:
O2 sensors have a negative wire, not a ground wire. THe body of the O2 sensor serves as a ground, or reffrence point for all O2 readings. The negative wire on the O2 sensor is for the heater circut in the O2 sensor. I'm pretty sure of this, to check, simply do a continuality check from the negative wire on the O2 sensor to the body of the O2 sensor. If their is continuality, then it is a bonified ground wire. Even if it is, its so small, that their is probably a significant voltage drop across it (with large enough current flow) to significantly alter O2 refference voltage. The ground strap would then help alleviate some of this voltage drop, giving a more accuate reason. THeir, I coverd both my bases.

16g-95GSX said:
well before you go changing your O2 sensor just yet, go under your car and check to see if the ground strap for your O2 sensor is grounded right. Mine wasn't and used to get only 14mpg, now i get around 20. So check urs out before doing that, because u might as well

ProjectGSX said:
That's awesome. With the strap connecting, I got around 275 a tank. My strap is currently broken, and now I get around 200 a tank.

Ps. Why is there a groung strap if it has no purpose? If mitsubishi made this engine so well(which is why we all love these cars I assume), why would they add the strap if it wasn't needed?

AWD_ENVY · Jan 21, 2002

If you've already read what people wrote, WHY are you asking again ???????

Jed · Jan 21, 2002

[QOUTE]
Ps. Why is there a groung strap if it has no purpose? If mitsubishi made this engine so well(which is why we all love these cars I assume), why would they add the strap if it wasn't needed? [/QUOTE]

Why the hell are you wasting our time on something you have an opinion on already..... and you obviously haven't worked on your car to much if you swear that mitsu engineers are that great...

mark93 · Jan 21, 2002

If you go to yahoo and use thier search engine there are plenty of sites which describe how a 1-2-3 or 4 wire o2 sensors work..thats what i did!

ieatv8s · Jan 21, 2002

Also if you hook up a jumptronix or similar to monitor O2 voltages you will notice the voltage stays the same with or without the ground strap(s) connected.
I believe the whole ground strap affecting your mileage is an old myth.

])rala · Jan 21, 2002

all i am saying is its a valid question...

and i didn't think i needed to tell you that was sarcasm regardung thier engineering

ProjectGSX · Jan 21, 2002

ieatv8s said:
I believe the whole ground strap affecting your mileage is an old myth.

Well, apparently my car belives the myth because my MPG went to shit when the ground strap was cut.

ntexdsmracer · Jan 21, 2002

ProjectGSX said:
Well, apparently my car belives the myth because my MPG went to shit when the ground strap was cut.

I agree, mine went to shit also. I left if off on accident, when I installed my test pipe, and I went from 350 miles to a tank to like 270 miles, now my O2 is out in the front and I am only getting 175 miles to a tank. I would just have to say it all helps. My 2 cents worth.

])rala · Jan 21, 2002

Thanks for the backup fellas. I thought it was a reasonable question to ask about since lots of peeps have said they noticed a difference. I noticed in the posts that there a few actual figures stated thats why i asked "8-10? More or less?" Well despite ieatv8s' and mark93's advice i got a new groundstrap and sanded the mounting points yesterday. I also filled up my tank with 94 octane pump gas(gotta love Sunoco) perfect timing for prices to be 51.9/l or 1.96/gl.

So i will see if there is any improvement within the next week. I will also post my findings here so there are more figures regarding this on the forum.

Ps I have seen ieatv8s preachings about how to calculate mpg and mpl....so my figures will be up to your level of accuracy

(<--sarcasm in case you can't figure it out)

Once again thank you to all who actually have noticed a correalation between the ground strap and mpg.

Dyesin · Jan 21, 2002

My gas mileage was also shitty for a long time until I finally reconnected the

ground strap to my aftermarket downpipe

mark93 · Jan 22, 2002

To anyone who is interested in this thread i did some research with an extra o2 sensor i had handy. I already said there are 4wires 2 for the heated element. And i found that there is a ground from the ecu BUT it also is grounding the casing of the o2 sensor . Then your 4th wire which is your +voltage.
So if you do have a bad ground on your exhaust and/or your engine, it May affect the performance of the o2 sensor.

Damn I hate being wrong!!

])rala · Jan 22, 2002

i admire your honesty...alot of people wouldn't be big enough to admit when they might be wrong. Thank you for your honest and useful input.

ieatv8s · Jan 22, 2002

mark93 said:
And i found that there is a ground from the ecu BUT it also is grounding the casing of the o2 sensor.

So what you have found is that there IS a ground from the ECU to the sensor. That means that if the strap is present or not the sensor is still grounded.

mark93 · Jan 22, 2002

Yes it is still grounded to the ecu(via the white wire) And to the o2 casing housing.

The only thing i can say is if reattaching the strap works..great go for it.

jw · Jan 22, 2002

The ground strap ensures that you have a good ground to the O2 sensor. If your O2 sensor is properly grounded, the ground strap would have no effect. But most of the time, our cars suffer from bad grounding issues when the wires oxidize and increase impedance. So, in that case, it will affect gas mileage.
It really doesnt hurt to have a strap.

disconnected ground strap=how much mpg lost?

])rala

ieatv8s

])rala

mark93

ieatv8s

])rala

AWD_ENVY

Jed

mark93

ieatv8s

])rala

ProjectGSX

ntexdsmracer

])rala

Dyesin

mark93

])rala

ieatv8s

mark93

jw

Top Contributors this Month

Recommended Communities