What did you do to / for your E53 today??

[Happy]

Originally Posted by Salty B.

Is it normal for one of the pre-cat sensors reading to jump all over from 0.09

It’s worn at 0.09, time to replace it.


E53 RiPPeR
XOuTPoST jUNkiE
ReVELaTiON 22:21

[X5chemist]

I agree. I like to see pre cats from 0.2-0.8 voltage.

[80stech]

The sensor circuit that isn't swinging from high to low and back is the problem.

[Salty B.]

I guess as long as I'm at it it'd be dumb not to replace em all. There's four total? $$$

Consequences of ignoring the problem? She runs fine and there's no emissions check here.

[Fifty150hs]

Originally Posted by 80stech

The sensor circuit that isn't swinging from high to low and back is the problem.

From my research this is correct on the upstream cats. The voltage will vary up and down and as long it is varying between .01 and 1.0V it is within expected range. If it isn't moving up and down it is bad. The downstream cats should show very small change, same voltage range, so if those are swinging up and down they're potentially bad.

[HofmeisterKink]

Not sure if cleaning is enough of a thing to post here(?) but I'm pretty pleased with my efforts 🙂

I went to clean the trunk and ended up taking it all apart 😆 - I even tackled the drop-down tailgate and cleaned the gunked-up locks, but I got so into it that I forgot to take any photos.

It was satisfying to obliterate 20 years of dirt buildup! Now I have some rust treatment to take care of... 🛠️

[Homerlovesbeer]

Haha nice work

[Salty B.]

Originally Posted by Salty B.

I guess as long as I'm at it it'd be dumb not to replace em all. There's four total? $$$

Consequences of ignoring the problem? She runs fine and there's no emissions check here.

Bump...

Can anyone ID which one might be bad? Or should I just bite the bullet and replace all four? Rockauto has some decent prices.

And if I ignore the problem will that cause anything bad to happen?

[Salty B.]

Originally Posted by HofmeisterKink

Not sure if cleaning is enough of a thing to post here(?) but I'm pretty pleased with my efforts 🙂

I went to clean the trunk and ended up taking it all apart 😆 - I even tackled the drop-down tailgate and cleaned the gunked-up locks, but I got so into it that I forgot to take any photos.

It was satisfying to obliterate 20 years of dirt buildup! Now I have some rust treatment to take care of... 🛠️

One of the first things I did to mine after I got it two years ago. It was prety crusty!

[Fifty150hs]

Originally Posted by Salty B.

Bump...

Are there two per bank/cat as implied here? https://www.realoem.com/bmw/enUS/sho...diagId=18_2088

And if I ignore the problem will that cause anything bad to happen?

Yes, two per bank. Two upstream and two downstream. Precat and postcat. Depends on how the sensors are allowing rich or lean condition. Too lean could lead to detonation and burnt valves. Too rich kills your fuel mileage and I think too rich is hard on the cats and can burn them out. Not to mention the constant SES light being on. That would make me nuts.