Author Topic: Bad O2 sensor symptoms?? (Read 9459 times)

Jorgeconrico · « **on:** June 02, 2009, 10:03:53 PM »

Was just wondering what some of the symptoms of a failing O2 sensor would be?:confused:

My car seems to cut out at 5500 rpm and stumbles at 4000rpm, but otherwise idles and runs fine. However it only has these symptoms when warm. Ive ordered a fuel filter and ngk plugs to see if this would fix the problem. I have a hunch that it won't.

JP 91iS · « **Reply #1 on:** June 02, 2009, 10:27:13 PM »

Sounds like a good place to start. Being that it only happens when warm may indicate o2 sensor. Did you check the wire in your engine bay (re: hot start problem) ?

RidingSimple · « **Reply #2 on:** June 02, 2009, 10:28:56 PM »

poor gas mileage.
poor performance.
just buy a new one, can't hurt.

Jorgeconrico · « **Reply #3 on:** June 02, 2009, 10:37:08 PM »

No i haven't checked the wire, but it doesn't seem to shake violently or run poorly after the engine is warmed up. I can start the car warm and it idles and accelerates smoothly until 5500rpm where it cuts of. Could the car be going into some kind of "safe" mode because it knows a sensor is going? BTW there are no engine lights that come on.

beemer1 · « **Reply #4 on:** June 02, 2009, 10:40:18 PM »

Quote from: Jorgeconrico;72903

Was just wondering what some of the symptoms of a failing O2 sensor would be?:confused:

My car seems to cut out at 5500 rpm and stumbles at 4000rpm, but otherwise idles and runs fine. However it only has these symptoms when warm. Ive ordered a fuel filter and ngk plugs to see if this would fix the problem. I have a hunch that it won't.

I had a similar problem. The more gas I gave it the more it cut out. I had to pull over every so often to let it cool down before I resumed my trip. Stomp test reavealed it was a lambda sensor (O2 sensor). Changed it out and problem solved.

When was the last time the 02 sensor was changed?

Steve

Jorgeconrico · « **Reply #5 on:** June 02, 2009, 11:00:27 PM »

My car hasn't reached that point yet, but I don't want it to. I can drive the car maybe 15 miles or so before this starts. On a good note the car is still drivable even with this fault. To answer your question i honestly don't know when it was last changed, but i can tell you it has about 165,000 miles.

beemer1 · « **Reply #6 on:** June 02, 2009, 11:07:02 PM »

Try the stomp test first and see if it reveals any codes.

Yeah I was on my way from NY to SC (720 miles) and half way through Virginia this happened. A 10.5 hr drive turned into 15 hrs :eek:

Change it before it becomes a real problem, if it is the problem.

Steve

Jorgeconrico · « **Reply #7 on:** June 02, 2009, 11:17:29 PM »

Don't have access to a code scanner. Damn. New 02 sensor it is.....

Or could it be the camshaft position sensor.......O WTF:mad:

B318M42W · « **Reply #8 on:** June 03, 2009, 12:59:53 AM »

stomp test... turn the key to the on position and then fully depress 5 times the gas pedal. check engine light should start flashing out codes... no scanner needed

JP 91iS · « **Reply #9 on:** June 03, 2009, 07:22:55 AM »

Here are some links I found.

The fault codes can be obtained with no code reader - our motronic systems have a built in diagnostics readout.

Fault Codes:
Stomp Test Procedure

A cheap option for the oxygen sensor is to buy one that fits a Ford Mustang and splice on the connection from your old o2 sensor.

Oxygen Sensor:
Pelican Parts DIY
Mustang Oxygen Sensor

Jorgeconrico · « **Reply #10 on:** June 03, 2009, 07:32:57 AM »

I was under the impression that i needed a scanner tool......

Guess I don't, hence the name stomp test. Thanks guys:D

BTW if i was on any other BMW forum i would have been ripped apart (that's why i came here). Thanks for helping.

Jorgeconrico · « **Reply #11 on:** June 03, 2009, 08:01:53 AM »

Already put in an order for a new O2 sensor, but i just did the stomp test and it revealed 1244 which i believe is the camshaft sensor......awesome:rolleyes:

DesktopDave · « **Reply #12 on:** June 03, 2009, 08:27:45 AM »

Yep - these cars were way ahead of their time. BTW, I don't want to rain on anyone's parade, but the stomp test is just for getting hints. For instance, sometimes a bad O2 sensor or AFM error can be caused by vacuum leaks. The ECU/DME cannot compensate for shorts or component failures, and it only tests a limited number of components.

Double-check everything with your multimeter before tossing it...they might be perfectly good.

Having said all that, I'm going to get me a Mustang O2 sensor and splice it in soon. They wear out after 80k miles or so and you can improve both mileage and engine life with them...

Jorgeconrico · « **Reply #13 on:** June 03, 2009, 08:40:48 AM »

Well i managed to cancel my order for the 02 sensor. Dave, if i were to test the camshaft position sensor with a multimeter what type of numbers am i looking for if this sensor is indeed working. Around 1250 ohms???

Jorgeconrico · « **Reply #14 on:** June 03, 2009, 03:01:52 PM »

Pulled out the cam sensor and there was fresh motor oil on it. Not a lot but enough for me to ask if its normal. I tested the sensor on the side with 3 prongs and it came very close to 1250 ohms (tested between prong one and two). I think this is the correct test procedure, but at this point i don't know. I'm getting a 1244 but the cam sensor seems fine.:confused::confused::confused: