Fuel/Air Ratio Sensor Problems

[candybeans]

Hi gang,

I've searched the forums but haven't found an answer to my specific problem. Hoping some of you more experienced enthusiasts can help.

Six weeks ago my 1998 Camry LE (4-cylinder, 175K) began hesitating and sputtering when accelerating. The problem was intermittent, but was getting worse. I took it into our friendly Toyota dealership for a diagnosis and they said that the Fuel/Air Ratio Sensor needed to be replaced (we live in California). They wanted $550. Being a frugal shade-tree mechanic I just slipped down to my local auto parts store and bought one myself for $121 and installed it.

To my surprise, the problem got much worse. And the car became difficult to start. And there was a curious amount of smoke coming from the new sensor (smelled like burning plastic, not exhaust, and no, I didn't leave the plastic cap on the sensor when I installed it). THe next morning the battery was dead and had to be jumped. Battery died again. Seems like a problem with the alternator, but why would replacing that sensor effect the alternator? We've never had any battery or alternator problems before this, and I think it's too much of a coincidence that it happened during this repair for it to not be related.

I reinstalled the old sensor to see if that changed things. It also began to smoke.

Any ideas?

Thanks--

Candice
1998 Camry LE (4-banger)

[Mister_Perkins]

If your battery is weak from the alternator not pushing voltage it could be sending the ECM a weak signal, in turn causing the car to run weird.

[Handsonmaxima]

Originally Posted by Mister_Perkins

If your battery is weak from the alternator not pushing voltage it could be sending the ECM a weak signal, in turn causing the car to run weird.

If the battery was low while the car was running the alternator would be running the car and charging the battery, the 14.7v coming from it would be more than enough to compensate, my weekend car doesnt even have a battery. i just roll start it everywhere.
Id say the A/F fried and is now causing parasitic drain on the system. return it to napa and try again. if they wont take a refund i have a spare sensor i can mail to you for price of shipping. but i am worried as to why it started to smoke when you reinstalled the orginal part.

[candybeans]

yeah, if it is the new air sensor, the smoke after it was removed and the old one (that didn't smoke) was replaced is confusing. I put the old sensor back before jumping the battery, and it drained again (we started it a couple more times after removing the jumper cables); wouldn't removing the bad sensor immediately stop the drain on the battery? Or is there something else I'm missing.

Thanks so much for the help! I really appreciate it.

[Mister_Perkins]

if you want to find whats shorting, turn off everything inside the car, make sure the doors closed, and disconnect both battery terminals. Remove 1 fuse at a time, connect the terminals to the battery. If it sparks reinstall the fuse again and pull the next fuse. Keep doing this until it doesnt spark. Once it doesnt spark, find out what fuse it is and we can help you find out where the wiring runs.

[Ted Striker]

It's possible you got the wrong type of sensor, when you got it did they ask if your car was Federal , 50 state or California emission?(it's possible the car came from somewhere else or they gave you the wrong one) The Federal has an o2 sensor, the Califrnia has an A/F sensor.I've seen dealers screw this up too, the parts catalog from Toyota won't tell you by vin, it asks you about the emission sticker. They look alike and in most cases plug right in but are wired completely different. It's possible you shorted out the heater circuit and that's why it smoked or drained the battery. It's also possible you fried the ECM. I believe your car has an A/F sensor relay if it has A/F sensors try removing it and see if your draw goes away. I think it's in one of the small relay boxes near the passenger headlight or in the main relay box itself. If you got lucky it may have just fried the A/F relay.

Im curious though, if you rev the motor for a few minutes does the manifold get cherry red? I have seen these clog cats up causing your symptom.

[Woodyg]

Originally Posted by Ted Striker

It's possible you got the wrong type of sensor, when you got it did they ask if your car was Federal , 50 state or California emission?(it's possible the car came from somewhere else or they gave you the wrong one) The Federal has an o2 sensor, the Califrnia has an A/F sensor.I've seen dealers screw this up too, the parts catalog from Toyota won't tell you by vin, it asks you about the emission sticker. They look alike and in most cases plug right in but are wired completely different. It's possible you shorted out the heater circuit and that's why it smoked or drained the battery. It's also possible you fried the ECM. I believe your car has an A/F sensor relay if it has A/F sensors try removing it and see if your draw goes away. I think it's in one of the small relay boxes near the passenger headlight or in the main relay box itself. If you got lucky it may have just fried the A/F relay.

Im curious though, if you rev the motor for a few minutes does the manifold get cherry red? I have seen these clog cats up causing your symptom.

I have the same car as the OP. I am having a p1130 issue........I removed my front "oxygen sensor" and got the part #. it is a denso 2349024 $98 at rockauto. the part is actually called an air fuel ratio sensor as mentioned earlier. my car was built in Japan, sold in Buffalo but has the California emissions........check the part # from the old sensor

[JohnGD]

Many times you have to double check the diagnosis. Obviously plenty are wrong. Take it to Autozone or other parts stores that offer free alternator and battery checks.

Did you properly torqued down the sensor? Autozone has free loaner sensor sockets. First of all the sensor should not smoke.

Use a voltmeter to measure the voltage with the engine off and running. When running it should be between 13.5-14.5v. With the engine off at least 3-4 hours it shouldn't dip below 12v. You can also do a current draw test by putting the multimeter in amps mode. Harbor Freight has these coupons in magazines giving away free multimeters with any purchase, like a $0.99 socket or something.

[candybeans]

Thanks for all the thoughts. I have an update. This morning, I checked to make sure that I have the correct sensor in the car. According to the Bosch catalog and the emissions sticker under the hood, I do have the correct part (Bosch #13733 Wideband A/F Sensor).

With the new air fuel ratio sensor installed there is no improvement in the acceleration/stuttering problems I experienced before this saga began. In fact, the problem seems worse. Still more concerning is what appears to be a drain on the battery while the engine is not running. If I start the car and drive it, then turn it off and immediately restart it, the car starts normally. If I let it sit for a few hours, it struggles to turn over in that distinctly dead-battery way. If I leave it overnight it doesn't start in the morning. This suggests to me that the alternator is functioning normally (the battery is charged after driving), but that a drain on the battery is occurring while the car is off. I struggle to understand how installing a new fuel air sensor could induce drain on the battery. How could this cause a short?

The smoke I saw from the sensor is no longer present. Could that have just been the anti-seize solvent I spread onto the threads burning off? Seems plausible, but I defer to the experts here.

Short of taking it to the mechanic, which would feel like a huge defeat at this point, what else can I do?

All ideas are welcome. You guys have been a big help so far.

Candice

[JohnGD]

I don't know what kind of antiseize you used, but it's a possibility as the cause of the smoke.

I'd take it to Autozone for a free charging/battery check. If you need a new battery I'd get one of their Duralast or Duralast Gold batteries (no Valucraft however).

Is the check engine light on? After the ECU is getting the right power I would look into the EGR system or fuel pump/filter.

[7stwman]

I'm just a shade tree mechanic my self and Newbee.

But, You could try unpluging the A/F senser overnight and see if the battery drains.

[Ted Striker]

Originally Posted by JohnGD

I don't know what kind of antiseize you used, but it's a possibility as the cause of the smoke.

I'd take it to Autozone for a free charging/battery check. If you need a new battery I'd get one of their Duralast or Duralast Gold batteries (no Valucraft however). skip the guessanostics warehouse and have a qualified tech check it out. Their batteries are junk IMO, as is the alternator you'll end up buying when the battery doesn't fix it.

Don't let your pride cause you to waste a bunch of money.

Is the check engine light on? After the ECU is getting the right power I would look into the EGR system or fuel pump/filter.

Toyota fuel pumps and filters rarely if ever fail. I've only been working on them 20 years, so what do I know?

There are some problems a DIY isn't going to be able to fix. The key is knowing your limitations. As a professional I understand the feeling of wanting to fix it.
It took me many years to learn what I know. People kid themselves sometimes into thinking that diagnostics are easy and should be cheap.

[candybeans]

Ok, I have another update! I replaced the spark plugs, which was another suggestion from the Toyota dealership, and that solved the hesitation/sputtering issue. But, the battery was still low on juice, but charged enough to start the car (barely). Just to see if the A/F sensor was the drain on the battery, we unplugged it for a night. When I went out to start my car the next day, the battery was dead. As I don't have another way to get around right now (and it seems like a waste of a AAA jump), I can't get the battery tested, by a guessanostician or anyone else. We did use a voltmeter on the battery while it wasn't running, and got a 12.3 reading, which was low, according to other battery-related forum posts I've seen.
Since my knowledge and mobility are limited, the only diagnostic i've left is the fuse test that Mister_Perkins suggested above. Anything else anyone can think of? Have I simply gotten to that point where I have to call in a professional? On that note, does anyone know of a good toyota mechanic on LA's west side? I've no love for my local dealership.

[fenixus]

if the battery is 5 or more years old it's probably junk already. get something decent with 700-750 Cold Cranking Amps (no, Toyota batteries are much weaker than that), it will last you longer. once running get the car's alternator tested at Autozone (free service), you can also test the old battery for free over there (likely it's garbage anyways).

Bosch sensors are crap if you ask me, on Toyotas always stick with Denso or NGK/NTK brands for o2/AFR sensors or spark plugs (and wires) and you will be well for long.

make sure you torqued it down properly until the crush washer sits flush. it takes 32ft-lbs to make it sit tight if I remember right.

my "friendly" local dealership (East Coast Toyota with Service dept in Carlstadt, NJ) is a bunch of crooks and I hate them, their service advisers lie with a smile on their faces and try pulling as much money from you as they can (I bet they get a % of invoice price).
However their techs and parts guys are mostly OK. be careful who you are dealing with. Some dealerships suck big times, they will try bending you over ... but yeah you get free coffee in return ... god I hate salesmen ...

it never hurts to get a second opinion from another shop.

the source of smoke was probably an excess of some non-heat-resistant anti-seize. if you do not get CEL now, then it's all good. if you do, get it scanned and fix the source, doesn't have to be related to sensor replacement, but of course (possibly & probably) it can.