Not joined yet? Register for free and enjoy features such as alerts, private messaging and viewing latest posts and topics.

Rough idle - driven mad

Starachell
Newbie
Newbie
Posts: 39
Joined: Wed Sep 10, 2014 8:10 pm

Rough idle - driven mad

Post by Starachell » Sat Apr 29, 2023 11:59 am

Just to add more confusion into the mix, I've taken the car to my specialist and the ambient temperature to the DME is -48. Other temperature readings normal. She'll have to go back in for another hour of diagnostics but those seems to pull away from the idea of it being fuel pump and moving towards a sensor issue or the DME is failing. We're going to check everything else over in the meantime as well.

Starachell
Newbie
Newbie
Posts: 39
Joined: Wed Sep 10, 2014 8:10 pm

Rough idle - driven mad

Post by Starachell » Sat Apr 29, 2023 12:01 pm

matsmith749 wrote: Sat Apr 29, 2023 11:15 am Googleing around for you - someone solved the 2d06 air MAF code by cleaning the oil cap!

Standard troubleshooting is to clean / replace the MAF, if fault remains you have air coming in from somewhere.

Might be worth checking / cleaning all the caps just in case it is something so simple as per the previous forum member - you could get lucky!
Thank you! I've seen the oil cap issue come up as well so it's worth a try. With the car sailing through the smoke test and 2 new MAFs installed, it feels like it's a miscommunication between the MAF and something else.

Starachell
Newbie
Newbie
Posts: 39
Joined: Wed Sep 10, 2014 8:10 pm

Rough idle - driven mad

Post by Starachell » Sat Apr 29, 2023 12:07 pm

colb wrote: Sat Apr 29, 2023 11:53 am Hope the Maf that was replaced was an OEM part, from experience cheap Mafs are a waste of time, they don't work or if they do dont last long, only fit oem Bosch or Seimens expensive but they work.
The MAF is continental - both times changed under warranty and they used the same part. But, it has been replaced twice and the smoke test was fine. The specialist has just read the codes again and now we've found the ambient (flow) temperature to the DME is reading -48. Now, could be the reader having a moment or it could be a lead to follow. If it is, it suggests there's something electrical going on. Would explain why the exhaust is coked up if the car is trying to pull too much fuel.

ori
Senior Member
Senior Member
Posts: 1497
Joined: Sun Mar 18, 2012 4:04 pm

Rough idle - driven mad

Post by ori » Sat Apr 29, 2023 1:21 pm

That’s a promising lead.

A reading that far out would 100% cause running issues.
Concern is, is it a sensor or cabling issue?

User avatar
B21
Lifer
Lifer
Posts: 5331
Joined: Tue Oct 05, 2021 7:15 pm
Location: In my Banana Yellow Space Shuttle...somewhere over Southern Caledonia

Rough idle - driven mad

Post by B21 » Sat Apr 29, 2023 1:33 pm

If the coolant temp is reading that number then that will probably throw a spanner in the works..probably massively rich…?
We choose to go to on with this endeavour at this time and do the other things, not because they are easy, but because they are hard..

Starachell
Newbie
Newbie
Posts: 39
Joined: Wed Sep 10, 2014 8:10 pm

Rough idle - driven mad

Post by Starachell » Sat Apr 29, 2023 8:23 pm

ori wrote: Sat Apr 29, 2023 1:21 pm That’s a promising lead.

A reading that far out would 100% cause running issues.
Concern is, is it a sensor or cabling issue?
Exactly that, or is it something within the DME. Best case scenario is a sensor that's gone rogue and is lying to the DME. Where that sensor is though is another issue. The previous owner used the car so infrequently that I worry about wiring as well, though I think the car was, at least aesthetically, protected..

Starachell
Newbie
Newbie
Posts: 39
Joined: Wed Sep 10, 2014 8:10 pm

Rough idle - driven mad

Post by Starachell » Sat Apr 29, 2023 8:24 pm

B21 wrote: Sat Apr 29, 2023 1:33 pm If the coolant temp is reading that number then that will probably throw a spanner in the works..probably massively rich…?
Absolutely, she smells rich and the exhaust is coked. I can also go through fuel like I'm getting kickbacks from the oil execs. I feel this is probably the closest I've gotten to the pieces fitting together. The previous suggestion of a fuel pump and the intermittent nature didn't seem to gel.

User avatar
B21
Lifer
Lifer
Posts: 5331
Joined: Tue Oct 05, 2021 7:15 pm
Location: In my Banana Yellow Space Shuttle...somewhere over Southern Caledonia

Rough idle - driven mad

Post by B21 » Sun Apr 30, 2023 11:32 am

Starachell wrote: Sat Apr 29, 2023 8:24 pm
B21 wrote: Sat Apr 29, 2023 1:33 pm If the coolant temp is reading that number then that will probably throw a spanner in the works..probably massively rich…?
Absolutely, she smells rich and the exhaust is coked. I can also go through fuel like I'm getting kickbacks from the oil execs. I feel this is probably the closest I've gotten to the pieces fitting together. The previous suggestion of a fuel pump and the intermittent nature didn't seem to gel.
On the N20 engine failure of that sensor causes those issues, appreciate it’s not the same engine but…
We choose to go to on with this endeavour at this time and do the other things, not because they are easy, but because they are hard..

matsmith749
Member
Member
Posts: 585
Joined: Sun Jan 12, 2014 11:36 am

Rough idle - driven mad

Post by matsmith749 » Sun Apr 30, 2023 5:40 pm

Might be a good time to go buy a decent code reader - it’s a 5 minute job to see exactly what that sensor is doing.

Takes some of the guesswork out of the equation.
From Jan 2023 2016 e89 Z4 35is / mineral white / coral red interior / all the extras
SOLD 2010 e89 Z4 35is / space grey / coral red interior / all the extras
SOLD 2007 e85 Z4 3.0 si sport / midnight blue / champagne interior

Starachell
Newbie
Newbie
Posts: 39
Joined: Wed Sep 10, 2014 8:10 pm

Rough idle - driven mad

Post by Starachell » Sun Apr 30, 2023 7:16 pm

matsmith749 wrote: Sun Apr 30, 2023 5:40 pm Might be a good time to go buy a decent code reader - it’s a 5 minute job to see exactly what that sensor is doing.

Takes some of the guesswork out of the equation.
We're using Veepeak with Bimmer Link at the moment. The coolant sensor is fine and temperatures are normal. What we saw yesterday was something about ambient temperature to the DME so perhaps not coolant. The tech said he wasn't sure which sensor was giving the reading and whether it was actually embedded in the DME. They're going to call me on Tuesday with more of the specifics about it. They've suggested plugging it into ISTA to explore it further.

Starachell
Newbie
Newbie
Posts: 39
Joined: Wed Sep 10, 2014 8:10 pm

Rough idle - driven mad

Post by Starachell » Sun Apr 30, 2023 7:17 pm

B21 wrote: Sun Apr 30, 2023 11:32 am
Starachell wrote: Sat Apr 29, 2023 8:24 pm
B21 wrote: Sat Apr 29, 2023 1:33 pm If the coolant temp is reading that number then that will probably throw a spanner in the works..probably massively rich…?
Absolutely, she smells rich and the exhaust is coked. I can also go through fuel like I'm getting kickbacks from the oil execs. I feel this is probably the closest I've gotten to the pieces fitting together. The previous suggestion of a fuel pump and the intermittent nature didn't seem to gel.
On the N20 engine failure of that sensor causes those issues, appreciate it’s not the same engine but…
Just need to find the sensor that's at fault. I've also seen people say the -40 is an indication that the wiring has failed. I just hope the sensor isn't embedded in the DME.

flybobbie
Lifer
Lifer
Posts: 4017
Joined: Sat May 25, 2013 8:27 pm
Location: Stourbridge

Rough idle - driven mad

Post by flybobbie » Sun Apr 30, 2023 7:19 pm

What of the ambient temperature sensor, front left, bottom of wheel arch.
My cars went faulty, can't remember now why i changed it, but it had failed.
I think it went to -40c open circuit? I think roof stopped working.

I need to keep a diary.

Starachell
Newbie
Newbie
Posts: 39
Joined: Wed Sep 10, 2014 8:10 pm

Rough idle - driven mad

Post by Starachell » Sun Apr 30, 2023 7:44 pm

flybobbie wrote: Sun Apr 30, 2023 7:19 pm What of the ambient temperature sensor, front left, bottom of wheel arch.
My cars went faulty, can't remember now why i changed it, but it had failed.
I think it went to -40c open circuit? I think roof stopped working.

I need to keep a diary.
I feel like I need a diary at this point as well, if only to save me from going crazy! At the specialist yesterday the car didn't die at all. We've just been out to run the coder and it died 4 times :headbang: However, we did manage to read the ambient temperature from the wheel arch sensor and it was absolutely fine. We can't see where the ambient temperature in connection to the DME stems from.

Starachell
Newbie
Newbie
Posts: 39
Joined: Wed Sep 10, 2014 8:10 pm

Rough idle - driven mad

Post by Starachell » Wed Jun 07, 2023 2:35 pm

I wanted to jump on with an update of how things are going – or not, as is the case. Sparks and coil packs are all fine and operating as they should. I took the car to a second specialist for another opinion. They checked the DME for damage, none found, and reprogrammed the VVT as this was incorrectly stored in the car. I picked it up but the issue remained - rev and oil counters bouncing at idle and then the car stalled shortly after pulling into a parking space. Took it back to the same garage who then fitted a new temperature sensor but again, no luck. I’ve since taken the car to the dealership I bought it from and they've taken it to BMW. They claim BMW tested the car on the ramp for 2 hours and it didn’t fault, road tested it twice without issue, and of course the car didn’t die on the journey to or from the dealership. I’ve emphasized to them numerous times that it’s not the road testing that’s the issue, it’s the pulling over and stopping which then throws everything else off. I know the MAF fault code (2D06) was still showing when I dropped the car off so how BMW have explained that away I do not know. The dealership I bought the car from have left me with some particularly brilliant suggestions – am I sure it’s not just the stop/start even though the car doesn’t have that function and am I sure I’m not just trying to drive away from a red light in 2nd gear…… Next step is to take the dealer out for a test drive so that he can experience what’s happening. I’m really looking forward to more top tips from him in the process.

User avatar
enuff_zed
Lifer
Lifer
Posts: 14385
Joined: Wed Oct 26, 2016 11:05 am
Location: Attleborough, Norfolk

Rough idle - driven mad

Post by enuff_zed » Wed Jun 07, 2023 2:42 pm

Grasping at straws, but it sounds like it's something to do with an idle setting.
No expert on the N52, but does it have an idle control valve like the M54.
HQ of 'Norfolk Zed Rescue'.
Always happy to help if I can.

If the forum helped you, why not help the forum back. Thats the Z4 way! :thumbsup:
Image

Post Reply