Rebuilt S63 - Misfire Help!

[Chilled]

Originally Posted by DrVirz

I did get a compression tester that screws into plug thread, reading about 165 across all 8, so a bit low but definitely enough compression for the motor to run.

If the flex plate is damaged like previously discussed, will the crank angle sensor tell DME to cut fuel to affected cyls?

In a nutshell, there are no ISTA errors/codes now. The car idles rough (seems to be missing), particularly at approx 900rpm. Higher in the rev range it isn't as bad.

Does seem low, but if you were off time, you would prob get 0 compression. So that kinda a +. No idea on the flex plate, ours cranked but did not even try to start.

What timing kit did you use? A good one or a cheap fleabay knock off?

It probably needs to run for longer to get more codes, but thats kinda not a good idea.

Originally Posted by DrVirz

I ran the car and unplugged then plugged back in each individual coil (all 8). On the contrary to what I said yesterday, there is a slight difference when unplugging coil 2 and 4 (and every other coil), only slight however.

You did pull the injector plugs at the same time, yeah? Otherwise you should prob change that oil, put a couple of drops into the cylinders.

[Chilled]

Your o2 sensors are plugged in correctly? Just saw the other thread https://www.bimmerfest.com/threads/r...-elec.1460785/
and in line with the wrong plugs. Was wondering if criss-crossed the o2s?

Not the issue in this thread, but has pics.
https://f15.bimmerpost.com/forums/sh...2002137&page=7

[DrVirz]

I have done another comp test with another tester just to make sure. Cyl 1 and 8 are the lowest at 165, Cyl 2-7 range between 170-180.

I also did a leakdown test, all cylinders are fine, between 10-15%.

As for timing kit, I just used a cheap one however checked it (as best as possible) to check both slots were aligned.

o2 are definitely in correctly, I double and triple checked this a few weeks back. I have made this mistake before!

And yes, injector plugs were pulled at the same time.

At this point, I am going to try and get some eyes on the flex plate via the crank angle sensor plug hole to see if I can see anything out of the ordinary.

[Chilled]

Let us know if you see anything. I think at this point you may need to get oscilloscope and start looking at the signals. Just make sure you get something that is sensitive enough.

Or even take it to a shop.

[DrVirz]

Managed to get a mate to turn the motor by hand while I looked at the flex plate through the crank angle sensor hole. Looks to be perfectly true to me, so I don't think there's an issue there.

Anyone have a recommendation for an oscilloscope?

[Chilled]

I'm guessing you've checked and tested all the vacuum lines and teste the intake system, maybe something is badly cracked and letting allot of unmetered air in.

Granted, the MAF should through up an error in such a case.

No idea on oscilloscope. From the cheap-ish (for oscilloscope) Pico's seems to come up over and over and do seem to have nice HW and software especially the automotive stuff.


*very dumb idea*, since it runs smooth at higher revs. Is it worth taking for a spin and if it smooths out, or if you get a new set of errors?

[DrVirz]

Originally Posted by Chilled

I'm guessing you've checked and tested all the vacuum lines and teste the intake system, maybe something is badly cracked and letting allot of unmetered air in.

Granted, the MAF should through up an error in such a case.

No idea on oscilloscope. From the cheap-ish (for oscilloscope) Pico's seems to come up over and over and do seem to have nice HW and software especially the automotive stuff.


*very dumb idea*, since it runs smooth at higher revs. Is it worth taking for a spin and if it smooths out, or if you get a new set of errors?

Yes smoke tested intake and vacuum lines, all good there from what I can tell. I've ordered a new crank angle sensor (why not at this stage).

Pico was what I was thinking, I might see if I can pick one up locally.

I was thinking this too. I did take it for a brief drive, approx. 500m, didn't throw any codes. Quite rough when driving, doesn't feel/sound comfortable!

[stocktree]

Are cylinders 2 and 4 next to each other?
They use a shared ground on the coil? You check that?