Misfire? Coils/sparks or vanos?

skmattwell · Post by **skmattwell** » Mon May 03, 2021 5:05 pm

Hi guys, sorry if a noob question as I've only recently bought the car. Feel like it's one thing after another with issues at the moment...

Extremely rough at idle, rpms hop up and down wildly between 500-600. Whole car shudders but fine when driving. Is this a misfire or something more serious? Only happens when at a standstill.

Thanks in advance

skmattwell · Post by **skmattwell** » Mon May 03, 2021 5:10 pm

There is also a loud hissing noise from the engine bay

Mike6 · Post by **Mike6** » Mon May 03, 2021 5:10 pm

If you have only just purchased the car you really need to buy a cheap fault code reader and see what it tells you. My reader is called a Konnwei which was only cheap but is really good as it allows reseting of faults. I am sure other forum members will tell you exactly the same thing as your problem could be a whole range of things.

Mike6 · Post by **Mike6** » Mon May 03, 2021 5:12 pm

Check for leaks on the intake boot. They split after a while and are a cheap replacement. But still get yourself a code reader

BumpyZ4 · Post by **BumpyZ4** » Mon May 03, 2021 5:40 pm

Mike6 wrote: ↑Mon May 03, 2021 5:12 pm Check for leaks on the intake boot. They split after a while and are a cheap replacement. But still get yourself a code reader

Yep sounds like a vacuum/intake leak.

skmattwell · Post by **skmattwell** » Mon May 03, 2021 5:57 pm

Thanks guys, I have a code reader on order but listening to the engine bay I think you're spot on. Hissing seems to be coming from where the intake boot is located. For the sake of £30 it's worth replacing anyway.

Reckon it's an easy enough job for a beginner or shall I get it to a garage?

colb · Post by **colb** » Mon May 03, 2021 5:58 pm

That hissing noise is probably from a split intake hose or any of the other vaccum pipes across the engine, the symptoms you describe would be caused by an air leak. A code reader is a must for these cars and when you scan it you will probably find some codes related to fuel trims being exceeded, this is triggered by the air leaks you have and the exhaust sensors seeing the extra air in the exhaust as a lean mixture. The extra air will not have passed through the Maf sensor so with what the exhaust sensors see is a mismatch of air measurement from what went through the Maf and it thinks its running lean. To correct it the ECU will increase the fuel at the injectors and will do so until it gets to 20% more then give up and set the EML on the dash. Replace any holed rubber pipes you find and clear the codes with your reader, test run then scan again to see if any codes return.

skmattwell · Post by **skmattwell** » Wed May 05, 2021 9:21 pm

Quick update on this, replaced lower intake boot and symptoms/hissing is still there. Now I'm thinking ccv valve or disa valve o-ring? The hissing is definitely coming from that area but I can't pinpoint it.

Got a code reader and here's the long list of codes it gave me:
============1==============
FF00
Raw code: FF00
ECU: 12

============2==============
2882
Raw code: 2882
ECU: 12
Status: Pending fault present, Validated and stored in non volatile memory, Validated fault has been present during this drive cycle

============3==============
2883
Raw code: 2883
ECU: 12
Status: Pending fault present, Validated and stored in non volatile memory, Validated fault has been present during this drive cycle

============4==============
27A4
Raw code: 27A4
ECU: 12
Status: Test conditions are met

============5==============
289D
Raw code: 289D
ECU: 12
Status: Pending fault present, Validated and stored in non volatile memory

============6==============
279C
Raw code: 279C
ECU: 12
Status: Test conditions are met, Validated and stored in non volatile memory

============7==============
28F1
Raw code: 28F1
ECU: 12
Status: Pending fault present during this driving cycle, Validated and stored in non volatile memory

============8==============
27C3
Raw code: 27C3
ECU: 12
Status: Pending fault present

============9==============
29A1
Raw code: 29A1
ECU: 12
Status: Test conditions are met, Validated and stored in non volatile memory

============10==============
P0171
Raw code: 0171
ECU: 12
Status: Confirmed
OBDII: System too lean, bank 1
BMW: System Too Lean

============11==============
P0174
Raw code: 0174
ECU: 12
Status: Confirmed
OBDII: System too lean, bank 2
BMW: System Too Lean

============12==============
P0161
Raw code: 0161
ECU: 12
Status: Confirmed
OBDII: Heated oxygen sensor (HO2S) 2, bank 2, heater control - circuit malfunction
BMW: O2 Sensor Heater Circuit

============13==============
P1622
Raw code: 1622
ECU: 12
Status: Confirmed
OBDII: Immobilizer ID Does Not Match
BMW: MAP Cooling Control Circuit Electrical; Map Cooling Thermostat Control Circuit Electrical

============14==============
P2272
Raw code: 2272
ECU: 12
Status: Confirmed
OBDII: Heated oxygen sensor (HO2S) 2, bank 2 - signal stuck lean
BMW: O2 Sensor Signal Stuck Lean

============15==============
P0160
Raw code: 0160
ECU: 12
Status: Confirmed
OBDII: Heated oxygen sensor (HO2S) 2, bank 2 - no activity detected
BMW: O2 Sensor Circuit No Activity Detected

Haro · Post by **Haro** » Wed May 05, 2021 10:41 pm

Spray wd40 around the area to see where the idle rises.

colb · Post by **colb** » Wed May 05, 2021 11:20 pm

Still sounds like an air leak is there, best smoke test it if you cant find it visually, smoke should find any leaks. The Lean codes would also seem to confirm there is an air leak. The exhaust sensors are also suspect with heater circuit malfunctions and signal stuck codes.

BumpyZ4 · Post by **BumpyZ4** » Thu May 06, 2021 3:44 am

Looking at your codes you definitely have a intake/vacuum leak which is causing your engine to run lean. Like colb said a smoke machine is a good way to find it or spraying something like brake cleaner around the area until the engine RPM increases to pin point the leak.

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