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| Lambda Sensor/no Cat Issue | |
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| Tweet Topic Started: Fri Dec 7, 2007 12:43 pm (663 Views) | |
| tommosblackone | Fri Dec 7, 2007 12:43 pm Post #1 |
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Newbie
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Hello all, it's been a while since I last sought your advice, which must say something for the 190! Last year our 1.8e (1993) cat rusted through, so I cut it out and replaced it with a straight section of pipe. Although I say it myself, I made a CRACKING job of it! I also put in a new lambda sensor at the same time, simply because I noticed the old one was quite possibly the original! Since then, I've not driven it (it's the Missus' car), but today I've booked a day off work to try to do all the "winter" checks etc. on it. I noticed it has a severe flat spot when pulling away, at around 1000rpm. using full throttle it will clean up and pull through it. I checked my wiring on the new lambda sensor, as it was a bit of a guess at the time. I tried unplugging the sensor when the car was running, and it made NO DIFFERENCE at all to the way the car ran. AT ALL! What could this suggest? Surely the ECU will need the sensor in circuit to acheive the correct mixture? I'm sure this is the cause of the flat spot, as it's just had new filters, leads, plugs etc. Rotor arm/cap is spot on too. Any pointers gladly welcomed. PS the Lambda sensor was for the 190, but looks like a "universal" one. It has two white leads, and one other, possibly black. If I've run the car with it disconnected, would that have lodged a fault code? Cheers, a very cold Tommo! |
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| philhoward | Sun Dec 9, 2007 11:35 am Post #2 |
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Part of things
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I'm doing some looking into this one as i've removed my complete cat AND sensor - which now seems to be a daft idea... The lambda control loop kicks in when the engine is above a certain temperature (I think it's around 80 degrees - not sure yet) and not in WOT (wide open throttle). When cold/warming up, it doesn't kick in so you'll see/feel no difference. Now, i have no sensor anymore but this makes the ECU think the engine is running lean. At idle I can "feel" the engine hunting at 1 second intervals as the ECU richens it up, looking for the lambda sensor to change from lean to rich, then gives up. Nauturally, it won't, but my fuel economy has now gone down the pan! Somewhere (in an Engine section sticky, IIRC) is how to use the diagnostic socket to see if the Lambda sensor IS working. (pins 5 and 3 ring a bell, but best check first). I'm looking to disable the correction completely (I'm going to try frigging the WOT switch first...)... |
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| julian | Sun Dec 9, 2007 5:35 pm Post #3 |
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Addicted
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I was told that the only lambda sensor that works on the 190'; is an MB one, or the Bosche equivelent. The MB ones are Bosche and the wiring is specific to MB and the 190. However you can get a Bosche sensor that's identical except for the wiring which you need to slightly adapt to fit the 190 connections. Any lambda sensor other than the 2 mentioned will not work. I was told this by an X MB mechanic following a blown sensor on my old 2.0 He adapted a new bosche one as it was £20 quid cheaper than the MB equivilent. He had a computer program that matches the MB part No. to the correct matching Bosche part No. This was a few years ago so someone might produce lambda sensors for the 190 now. |
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9:28 AM Jul 11