M42club.com - Home of the BMW E30/E36 318i/iS
DISCUSSION => Engine + Driveline => Topic started by: Jorgeconrico on June 02, 2009, 10:03:53 PM
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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. :(
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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 (http://www.m42club.com/forums/showthread.php?t=7757)) ?
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poor gas mileage.
poor performance.
just buy a new one, can't hurt.
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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.
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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
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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.
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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
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Don't have access to a code scanner. Damn. New 02 sensor it is.....:D Or could it be the camshaft position sensor.......O WTF:mad:
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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
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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 (http://e30world.com/fuel/BMW-E30-DME-Motronic-fault-codes)
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 (http://www.pelicanparts.com/bmw/techarticles/E30-O2_Sensor/E30-O2_Sensor.htm)
Mustang Oxygen Sensor (http://e30world.com/fuel/BMW-E30-Oxygen-Sensor-Replacement)
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I was under the impression that i needed a scanner tool......:o 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.
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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:
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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...
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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???
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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:
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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:
If you have an M42 (like we all do), chances are the passenger (right) side of the timing case leaks...which, in turn gets the CPS wet with oil. Ask me how I know. :rolleyes:
And to reiterate what Dave mentioned above, I tested faulty AFM with the stomp test when I indeed had a loose vacuum hose. So not always 100% accurate.
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I did replace the "mess under the intake". Could the hoses i have be caving in under heavy vacuum. I'm using 5/8 heater hose from the intake boot to the ICV. Not strong enough? I would like to know what hose people are using. Perhaps the hoses heat up and become softer and more likely to compress under vacuum. That may explain why this problem exists only after driving 10-15 miles.
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I disconnected the battery to reset the codes (search function does work). It read 1444. I took the car out and drove it hard to see if the problem would return, it didn't. I thought that if i could get the car to cut out at 5500rpm again a code would appear, perhaps different from the first (1244). I did the stomp test once again and the code was still 1444.
Could the ECU/DME??? have remembered the past code of 1244, which would make it run as if the vac leak had not been fixed?
1244 is for cam sensor, but i guess this test is not accurate. Tell me if this even makes sense...my mind hurts.