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BMW 3-Series (E90 E92) Forum
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N52 Eccentric shaft sensor. HELP
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01-26-2023, 10:00 PM | #1 |
e90 323i
11
Rep 20
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Alright before we start the car is a 2007 e90 323i with an n52 (200hp same as European 325i) it also has 298,563kms on it. Valve cover and ALL gaskets were replaced less then 10,000km ago. Has ZERO codes runs smooth( besides irregular misfire)…
It recently started to misfire. Cylinder 3 was the culprit. But it was odd because the car would randomly start to misfire even after running fine for a while on a drive. But I pulled over shut the car off and started it agian and it was fine for a couple days. Then it did it again so I pulled over shut it off then started it agian and it was fine. So it being random like this I thought coils because they’ve NEVER been replaced. So I replaced all coils. But well I was doing that I saw the eccentric shaft sensor gasket was leaking. And knowing the potential problems. I inspected the sensor seal and noticed the NEW gasket was split and I can actually see into the engine… so I took the connector off and found this(see below). Mind you this gasket was replaced less then 10,000km ago. And in the pictures below you can obviously see that, well it’s bad. And in the second photo is the split in the gasket. But I also noticed the sensor seems kinda miss aligned. But it’s not loose ( i checked) so I’m going to ignore that right now. I’m going to try and replace the gasket with out taking the valve cover off because it leaks nowhere else. If unsuccessful I will resort to RTV. But the reason for this post. 1 opinions. 2 do you think the oils is coming up from the pins. Mind you the car runs fine.(I took it for a drive after replacing coils and no signs of misfire and was noticeable smoother.) 3 I really DO NOT want to take the valve cover off again. This is not a daily driver anymore so I have time to work on it. |
01-26-2023, 11:12 PM | #2 |
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The ESS connector I believe has a seal to prevent oil from getting onto the pins. Therefore I think it is more likely the oil is coming out of the sensor than into it.
However, given how easily it is to change that sensor seal, you can first clean off the oil with electronic parts cleaner, and replace the sensor seal. See if the problem returns. Make sure the plug to the #3 coil is fully seated. Use the electronic parts cleaner on the coil connector and coil pins too. Allow to fully dry. Given the valve cover is know to crack with age, if you remove it might as well put in a new cover. I use Uro. ESS seal. USD $1.60 plus shipping from Rockauto. https://www.rockauto.com/en/moreinfo...=17001&jsn=455 |
01-26-2023, 11:34 PM | #3 |
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01-26-2023, 11:49 PM | #4 | |||
e90 323i
11
Rep 20
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First off thank you for responding.
Yeah I’ve had problems with this and have made sure. Quote:
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So I’ve replaced the valve cover entirely because I believed it to be cracked near the valvetronic motor. But after installing the new valve cover there was still oil in the same area. And it turned out to be the valvetronic motor gasket the whole time. and I fixed it with RTV and hasent leaked since. It didn’t end up being cracked but oh well. The previous valve cover has as new ESS seal in it so I’m probably gonna rob that and install it in the new one. But I’m just worried about the oil pooling in the connecter leading to failure. |
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01-26-2023, 11:53 PM | #5 | |
Cometh
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Quote:
Clean the pins with electric contact cleaner and see if that makes a difference. I also have oil in my ESS plug with an intact gasket, and periodic cleaning has gotten me by without any codes so far. I hate that the ESS is buried under the valve cover. I would've replaced it while you had the valve cover off, especially at that mileage, but hindsight is 20/20. |
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01-27-2023, 12:03 AM | #6 | |
e90 323i
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Yeah unfortunately I wasn’t the owner of the car at the time we did repairs. So I didn’t have much of a say. |
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01-27-2023, 12:08 PM | #7 | |
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Quote:
I think the ESS internals are protected from oil with a conformal coating so failures happen when too much oil builds up in the plug area. Another thought is that some of the cleaner probably gets into the engine oil, but hopefully I change my oil frequently enough that it doesn't matter. |
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Lochstar810.50 |
01-28-2023, 03:38 PM | #8 |
e90 323i
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Rep 20
Posts |
The sensor seal swap was super easy would have done it awhile ago if I knew it was that easy. But it’s in and definitely dosent leak or leaks less. BUT the oil is definitely still coming up from the pins so. I cleaned it really well agian. put saran wrap on the connector put RTV on it and stuffed it in the connector. The rtv stuck too the Saran Wrap as I pulled it back out but the connector was clean and there was still some rtv at the bottom around the pins. I let it setup a little then put saran wrap with soap on it around the connector agian( so It wouldn’t stick) and let the rtv set up with the connector and saran wrapp pushing it down around the pins. Once dry I took it for a test drive let it get to full temp. (Wich in -25°c takes awhile). And got back home pulled the plug off and there was still a tiny bit of oil around 1 pin wich was lacking some RTV. but a lot less then when I tested how quick it filled with oil previously. Without the RTV. So I’m going to add a little more RTV and hope it at least slows it down.
And then I’ll still probably stuff the connector with dielectric grease. Thanks Loch. |
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The Nightman1066.50 |
03-28-2023, 03:57 PM | #9 |
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I came across the following service bulletin and it seems that oil contamination at the eccentric shaft sensor can travel to the DME and damage it too.
https://bmwrepairguide.com/sib/110616.pdf |
03-28-2023, 04:40 PM | #10 | |
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