Idle issues

[niklecce123]

Hi all,

I'm really trying to hunt down what is causing my rough idle. The car has zero codes, which makes the analysis not as easy.

The car runs great except at idle, it does not hesitate through its powerband. There's three weird things, 2 which make me think the throttle body is bad.

1. When revving the car, the car briefly dips in idle before revving powerfully, almost like there's a vacuum leak.
2. When I rev the car slowly, the car's idle briefly blips in speed and then returns to idle. I've been able to almost push the gas pedal halfway and the car is not holding the revs as it should. It just keeps blipping and returning to idle, blipping and returning to idle. Throughout this, I'm slowly pressing the gas pedal in more.
3. If I enable the AC, the idle increase to a steady 700 and purrs like a kitten.

I am going to smoke test the car later, but everything is new here. Every single gasket in the fuel intake systme is new, MAF is new (BOSCH), sparkplugs, PCV & OSV etc. There really is nothing that I haven't replaced, besides the fuel injectors. About a year ago, I replaced 3 coils, hoping to find a difference and there is no difference, so I stopped throwing parts there.

Any thoughts here? Could I have a bad throttle body? I will get a video of the issues when I slowly rev the car. I mean this engine runs great when I give it the beans, it's the idling that drives me nuts.

[niklecce123]

Sidenote: I've also noticed the cars idle gets rougher when I do the slow revving thing, it's almost like the throttle body isn't closing correctly all the way or something.
I checked the values in INPA and I cannot determine what the operating conditions should be, but with the car off, no gas pedal pressed, this is what I see:
no throttle off.jpg
WIth the gas pedal full pressed, car off:

WOT off.jpg

Here's the screenshot for when the car idling, about 95% warmed up:
analogvalues1.jpg

[Timm]

You need to check adaptations - all explained here:






- - - Updated - - -

It is worth saying thoigh - the M60, M62 and M62TUB always have a little stumble just as the throttle lifts from idle....

[niklecce123]

That’s exactly what I’m going to check tomorrow. I have the rear bumper off getting painted, and I really don’t like letting the car idle until it’s warmed up.

The adaptations will tell a lot, and frankly I’m hoping I find something there. I felt the injection time was high, as I do not the average for this engine. I will say it’s very hard to find technical details on the M62TU engines.

[TheAngryBear]

Not quite as useful as Timm’s site but I had started a project on my 540iA on Reference Values both to explain the various elements and give a baseline reading of when the engine wasn’t throwing codes. Renders the table in webview or desktop but on apps can sometimes give issues. Not saying it is gospel but at least another set of values to compare against.

https://www.bimmerfest.com/posts/9655928/


Sent from my iPhone using Tapatalk

[niklecce123]

I am very happy to report that a new camshaft sensor fixed the issue.

background:
when I bought the car, it had a code for bank 2 camshaft sensor. Replaced the sensor and code went away. I then went on to do the timing / VANOS job. I didn’t like the idea of using a 25 year old sensor in tandem with a brand new one from 2022. Car idles and runs like butter now.

[Panamera1988]

Not sure if read right, did you had now code for camshaft sensor that fixed the problem or there was no code?