My car's O2/Oxygen sensor is broken - is it safe to drive?

imported_Tomato

Diamond Member
Sep 11, 2002
7,608
0
0
Earlier today, my car's "Check Engine" light went on and I took it to a mechanic for a free diagnostic. It turns out my O2/Oxygen sensor is broken, and I need to have it replaced.

The mechanic quoted me $280 and told me that it should be taken care of immediately. Unfortunately I don't have $280 to spare right now... will my car explode or will the engine blow up, or is it safe to keep driving for a little while until I can afford to get it fixed?
 

AgaBoogaBoo

Lifer
Feb 16, 2003
26,107
4
81
Check it yourself, some mechanics want to make an extra $100 so they'll lie about what's actually wrong
 

SilverTorch

Golden Member
Oct 4, 2000
1,082
0
0
you should be fine, MPG will go down, but its ok to drive.

still I would get it replaced as soon as you have the money, better yet, make friends with gearheads :D

what car is it?
 

imported_Tomato

Diamond Member
Sep 11, 2002
7,608
0
0
Originally posted by: AgaBoogaBoo
Check it yourself, some mechanics want to make an extra $100 so they'll lie about what's actually wrong

Is there a way to check it myself? I don't know much about cars, unfortunately. :

I should have the money saved in about a month or so, is it okay to drive around for that long? I only take drive it to work and home every day (10 minute drive each way).

It's a 1994 Honda Civic EX 2-door coupe with about 150,000 miles. Would now be a good time to also save up for a 30k/60k/90k tuneup, as to my knowledge it's never had one?
 

Eli

Super Moderator | Elite Member
Oct 9, 1999
50,422
8
81
To the people saying it's OK.. I would tend to agree, but then the potential for a lean condition popped into my head.

Can a malfunctioning O2 sensor cause lean burn? If so.. you should probably have it fixed sooner than later, but chances are you'll be fine for a month.
 

TheNinja

Lifer
Jan 22, 2003
12,207
1
0
I swear mechanics always say "it's the O2 sensor". I don't even think cars have one, it's just something the mechanics like to say b/c they can make a lot of money for resetting your "service engine soon" light, either that or O2 sensors go out A LOT! In seriousness the O2 sensor must either be a high markup part/job or they do go out quite a bit.
 

Pepsi90919

Lifer
Oct 9, 1999
25,162
1
81
Originally posted by: Eli
To the people saying it's OK.. I would tend to agree, but then the potential for a lean condition popped into my head.

Can a malfunctioning O2 sensor cause lean burn? If so.. you should probably have it fixed sooner than later, but chances are you'll be fine for a month.

the computer goes into open loop when it sees an O2 sensor out of range, i'm sure the default values aren't gonna be too lean.
 

JulesMaximus

No Lifer
Jul 3, 2003
74,456
854
126
It's fine. Eventually the car just won't start. Could take weeks before that happens though. Probably won't pass smog until you get it fixed either.

Still, I'd get it fixed as soon as you have the money.

Oh, and cars do have O2 sensors. :roll: My Rodeo had 4 of them. They range in price but usually aren't more than $40-50 each and they aren't difficult to replace if you do it yourself.
 

Lotheron

Platinum Member
Oct 21, 2002
2,188
2
71
You'll use more gas, as it'll throw more gas into the cylendars to compensate for what it thinks is lack of oxygen, but for the most part you'll be fine. Itll hurt your spark plugs as they will get fouled up.

If you haven't had any tune ups, probably should do the basics, spark plugs, spark plug wires, air cleaner, etc etc. Check your manual if you want to do those.
 

Shawn

Lifer
Apr 20, 2003
32,237
53
91
Originally posted by: Eli
To the people saying it's OK.. I would tend to agree, but then the potential for a lean condition popped into my head.

Can a malfunctioning O2 sensor cause lean burn? If so.. you should probably have it fixed sooner than later, but chances are you'll be fine for a month.

I don't think so. If the ECU can't get a valid signal from the O2 sensor it will run rich. It'll just waste a lot of gas. Won't really hurt much.
 

Analog

Lifer
Jan 7, 2002
12,755
3
0
$280 for an O2???? Just do it youself!

I believe that your engine will not go closed loop with an O2 out. I.e. no EGR. You should be okay to drive it around, you will not, however, pass a smog test without EGR.
 

NutBucket

Lifer
Aug 30, 2000
27,033
545
126
Originally posted by: Tomato
Originally posted by: AgaBoogaBoo
Check it yourself, some mechanics want to make an extra $100 so they'll lie about what's actually wrong

Is there a way to check it myself? I don't know much about cars, unfortunately. :

I should have the money saved in about a month or so, is it okay to drive around for that long? I only take drive it to work and home every day (10 minute drive each way).

It's a 1994 Honda Civic EX 2-door coupe with about 150,000 miles. Would now be a good time to also save up for a 30k/60k/90k tuneup, as to my knowledge it's never had one?

Well it should have had some sort of major service in its lifetime. Timing belt is about 90k or so. Course, I don't know how many miles the car had on it when you got it.
 

Pepsi90919

Lifer
Oct 9, 1999
25,162
1
81
Originally posted by: JulesMaximus
It's fine. Eventually the car just won't start. Could take weeks before that happens though. Probably won't pass smog until you get it fixed either.

Still, I'd get it fixed as soon as you have the money.

:confused: no.
 

JulesMaximus

No Lifer
Jul 3, 2003
74,456
854
126
Originally posted by: Pepsi90919
Originally posted by: JulesMaximus
It's fine. Eventually the car just won't start. Could take weeks before that happens though. Probably won't pass smog until you get it fixed either.

Still, I'd get it fixed as soon as you have the money.

:confused: no.

Care to explain?
 

Pepsi90919

Lifer
Oct 9, 1999
25,162
1
81
Originally posted by: Slasher2k
You'll use more gas, as it'll throw more gas into the cylendars to compensate for what it thinks is lack of oxygen, but for the most part you'll be fine. Itll hurt your spark plugs as they will get fouled up.

If you haven't had any tune ups, probably should do the basics, spark plugs, spark plug wires, air cleaner, etc etc. Check your manual if you want to do those.

the computer is not listening to the oxygen sensor anymore. it has been deemed out of range. hence the MIL.
 

Pepsi90919

Lifer
Oct 9, 1999
25,162
1
81
Originally posted by: JulesMaximus
Originally posted by: Pepsi90919
Originally posted by: JulesMaximus
It's fine. Eventually the car just won't start. Could take weeks before that happens though. Probably won't pass smog until you get it fixed either.

Still, I'd get it fixed as soon as you have the money.

:confused: no.

Care to explain?

what would stop it from starting?
 

Linux23

Lifer
Apr 9, 2000
11,303
671
126
i heard the car may run too lean. happened with my old 2000 Maxima where I was going to Canada and the light came on. I got 28mpg coming and going on a car that normally got 20-22 mpg.

i think running lean for a long period of time can cause problems.
 

Pepsi90919

Lifer
Oct 9, 1999
25,162
1
81
Originally posted by: Linux23
i heard the car may run too lean. happened with my old 2000 Maxima where I was going to Canada and the light came on. I got 28mpg coming and going on a car that normally got 20-22 mpg.

i think running lean for a long period of time can cause problems.

it was probably on its way out, giving false readings, causing your low mileage. the default fuel map that the computer reverted to just happened to give you better mileage.
 

T2T III

Lifer
Oct 9, 1999
12,899
1
0
Originally posted by: yellowfiero
$280 for an O2???? Just do it youself!

I believe that your engine will not go closed loop with an O2 out. I.e. no EGR. You should be okay to drive it around, you will not, however, pass a smog test without EGR.

Actually, I just checked the parts prices at Advance Auto. Their prices (for the part) are between $75 and $302 for the O2 sensor for '94 Civic. The $75.00 is a universal one and I would stay away from that. From the looks of it, the mechanic might not be making too much in labor - considering the price of the parts.

 

imported_Tomato

Diamond Member
Sep 11, 2002
7,608
0
0
Thanks for all the feedback, it's quite helpful and to be honest I trust AT car buffs more than my local mechanic (who strongly insisted I fix it soon for safety issues..??).

I'm not very good with cars so I don't know if I could fix it myself - can you buy an Oxygen sensor from any auto parts store?

I actually have a smog check certificate I got on October 11... the car checked out fine then, but I suppose it wouldn't pass now. :\ Time to start saving, sigh.
 

JulesMaximus

No Lifer
Jul 3, 2003
74,456
854
126
Originally posted by: Pepsi90919
Originally posted by: JulesMaximus
Originally posted by: Pepsi90919
Originally posted by: JulesMaximus
It's fine. Eventually the car just won't start. Could take weeks before that happens though. Probably won't pass smog until you get it fixed either.

Still, I'd get it fixed as soon as you have the money.

:confused: no.

Care to explain?

what would stop it from starting?

I've had that happen on early 90s cars. They run poorly and eventually wouldn't start at all. Dunno why.
 

Pepsi90919

Lifer
Oct 9, 1999
25,162
1
81
Originally posted by: Tiles2Tech
Originally posted by: yellowfiero
$280 for an O2???? Just do it youself!

I believe that your engine will not go closed loop with an O2 out. I.e. no EGR. You should be okay to drive it around, you will not, however, pass a smog test without EGR.

Actually, I just checked the parts prices at Advance Auto. Their prices (for the part) are between $75 and $302 for the O2 sensor for '94 Civic. The $75.00 is a universal one and I would stay away from that. From the looks of it, the mechanic might not be making too much in labor - considering the price of the parts.

i think that was one of the first years for heated oxygen sensors for civics.
 

T2T III

Lifer
Oct 9, 1999
12,899
1
0
The O2 sensor for the '94 Civic have a recommended replacement interval of 100,000 miles.

 

Pepsi90919

Lifer
Oct 9, 1999
25,162
1
81
Originally posted by: JulesMaximus
Originally posted by: Pepsi90919
Originally posted by: JulesMaximus
Originally posted by: Pepsi90919
Originally posted by: JulesMaximus
It's fine. Eventually the car just won't start. Could take weeks before that happens though. Probably won't pass smog until you get it fixed either.

Still, I'd get it fixed as soon as you have the money.

:confused: no.

Care to explain?

what would stop it from starting?

I've had that happen on early 90s cars. They run poorly and eventually wouldn't start at all. Dunno why.

oh. dunno, maybe from the tons of carbon buildup that ensues from running too rich. it's a possibility i guess.