325is surging idle?

[Atara]

It makes sense, especially with the condition of the wire.

[StereoInstaller1]

If the CPS wire is occasionally shorting against something, then it could be the problem. The signal voltage is very low at idle, and can apparently reach 100v at redline. it's possible that there's a small enough intermittent short to only cause occasional issues.

Dude, what the fuck are you talking about?

The goddamn CPS is just a simple square wave, it does not change voltage at all.

You need to get your facts straight before you post re-fucking-tarded shit like that.

[Atara]

The problem has been a lot more consistent it seems. The past couple mornings it's been fairly cold and it runs pretty rough when I first start it up. I just sit there for a while with my foot steady on the gas at around 1500rpm. Once it stops lurching and warms up a bit I'll take it out and it drives fine. The only problem happens when I stop at a light, it'll lurch/stall if I don't go into neutral and give it a little gas.

[u3b3rg33k]

Dude, what the fuck are you talking about?

The goddamn CPS is just a simple square wave, it does not change voltage at all.

You need to get your facts straight before you post re-fucking-tarded shit like that.

Before you call me a dunce, go look up variable reluctance sensors, and the non square wave that they output.

Hell, tell you what, I'll for you.

http://www.megamanual.com/ms2/pickups.htm

[StereoInstaller1]

Before you call me a dunce, go look up variable reluctance sensors, and the non square wave that they output.

Hell, tell you what, I'll for you.

http://www.megamanual.com/ms2/pickups.htm

Wrong info, bucko. The CPS is not a variable reluctor (like the GM one they referenced) but a simple hall effect sensor. Does not raise voltage at all, unlike the GM one.

If you had ever worked on a GM HEI, you would know that. Look at the size of the GM sensor vs the BMW one...how the hell do you think that would generate 100V?

[u3b3rg33k]

Size has nothing to do with it.

Besides, if I'm wrong, why do people that sell PnP MS systems for e30s bother to to build in a VR decoder circuit?

[Atara]

I'm having the CPS(probably not causing the issue) and some other random things replaced tomorrow (vacuum lines & some basic maintenance stuff). I had the temperature sensor replaced and that didn't solve the issue I have in the morning. The car will run really rough and stall out a few times while idling before it starts going fine, this only happens in the morning as well. I've also noticed that sometimes when the car stalls after surging, the computer that shows time, mpg etc. will reset.

[u3b3rg33k]

How are your grounds? If you're seeing the clock reset, I have to think you have a power issue.

[Atara]

I've had a couple mechanics check it out and none of them could find a ground going off the intake manifold. I'll have that stuff checked out when I go to get the car worked on tomorrow.

[u3b3rg33k]

Why would you look there? Look at the + and - battery terminals, oil pan cable, etc.

[Atara]

Had a few tubes and some other stuff replaced. Ended up that the frayed wire wasn't the CPS but the oil pressure sensor (probably why the check oil light came on randomly). Still having the same issue though.

[Atara]

The car is really rough in the mornings, here's a video of just a little while ago. The car was like this for about 10 minutes before I decided to take the other car. I came back about 20 minutes later and it ran fine. One of the times it stalled the computer reset again (had the time/date set and had the time selected). When I started it up after the stall where the computer reset the temperature came up and started showing random numbers and then it went to this (as it usually does when it resets): http://img530.imageshack.us/img530/3555/image161f.jpg. When this happens the radio doesn't reset and ask for the code. Here's a video of this morning when it was running super rough, I had steady pressure on the gas as well.

[Atara]

I took it into a shop today and they smoke tested it and found a pretty big vacuum leak and fixed that. It fixed the stuttering when accelerating and I'll see how it starts from being cold now. The idling problem didn't get fixed though and they suggested that if it was still having the idle issues after the work they did that I should get a new idle control valve.

[clavinZERO]

I would also recommend checking the plug that goes into the Air Flow Meter. If you pull the boot back on that connector, you can check the condition of the harness there... check for loose wires from the bent position they always lay in AND inspect for wire insulation deterioration. Good luck on finding whatever it is.