330Ci E46 with High Idle

[feels1]

I live in Toronto, Canada. I have a 220k km 330Ci coupe auto, ZF transmission, sport package. Bought the car this January with high idle problem.

The idle is 800 - 900 rpm when warm, and steady. Typical value is 600-650. I have checked many used E46 cars and known that this is not just on paper, but actual value.

Initially, I thought it was due to common E46 issue, such as intake boot crack, MAF sensor dirty, DISA valve leaks, CCV crack or leak, valve cover crack/leak.

So I spent lots of time studying this forum and YouTube to fix all those myself, but the issue not resolve.

I have done following to try to isolate it further, but no luck

1. CCV/oil separator valves
2. Clean MAF sensor in intake boot
3. Air filter
4. DISA valve
5. Valve cover
6. Spark plugs
7. Lower intake boot
8. Clean throttle body
9. Clean ICV valve
10. Throttle body housing gasket
11. O-Ring in oil dip stick tube to oil pan
12. Seafoam cleaning in fuel tank, engine oil (and replaced it), through brake booster - Done 2 times
13. Entire cooling system
14. Double check fuel cap for crack or leak
15. Replaced F connector at intake boot
16. Replaced new BMW battery
17. VANOS rebuild
18. Replaced transmission fluid and filter
19. Replaced coolant
20. Replaced engine oil and oil filter
21. Replaced differential fluid

There is no Check Engine Light (CEL) or any code thrown. I have read almost every BMW E46 high idle issue, but 99% of them are talking about rough idle instead of steady high idle. Most of the above items are common known issues and maintenance, so I don't mind replacing them, but I am going crazy that this issue not resolve.

I drive 70% in city, so the high idle is just wasting the fuel, beside it is "pushing" my car when put into forward D gear or reverse R gear.

I run out of idea what I should replace next. Can the community provide me troubleshooting and/or possible reason for this issue?

Thanks in advance

[Siddy]

Does your pedal have to be adjusted? or re-calibrated?
I think to re-calibrate a fly-by-wire pedal you turn the key to ignition but don't start the car, then put your foot to the floor and hold it.

[feels1]

I tried throttle body reset procedure, which is 10 s on (Accessory mode), 10 s off, start engine. This doesn't resolve high RPM at all, and I certainly I don't feel any different in the throttle response. Any other suggestion?

Is there potentially a near faulty O2 sensor, or vacuum leak?

[MarcoZandrini]

A bad O2 sensor won't affect idle. A vacuum leak would cause the idle to fluctuate.

Do the engine idle ok when the engine is cold?

Does the problem occur when the MAF is disconnected?

[feels1]

Hi MarcoZandrini,

Firstly, appreciate your help.

The idle is 800 - 900 after warm and 900 - 1100 at cold start (100 rpm higher), both with fan off.

With with without MAF disconnected, the idle is about the same for cold engine and warm engine. During connecting and disconnecting the MAF sensor connector, the idle will drop for a short time before bounce back to the same value, and steady.

I don't know what is the rpm with MAF disconnected. This is not in the spec, and other members never tell what the rpm is, and only indicating it is steady. For me, it is steady, and having same rpm with or without MAF connected.

Up until now, I don't suspect it is the MAF sensor because other owner has been saying a bad MAF will cause low rpm, or rough rpm, but mine is steady at 800-900 rpm (warm engine). Disconnecting it causing DME to run with preset TPS and default fuel maps, which I don't know whether the rpm should be.

Kindly advise

[MarcoZandrini]

By disconnecting the maf the ECU goes into a default mode. That its, the ECU ignores the data from the O2 sensors and uses a pre-programmed fuel-air "map." Disconnecting the maf is one way to see if there are vacuum leaks.

Your case is very weird. You have to assume that the ECU is getting engine speed data from the crank position sensor. So, unless the ECU is flaky, the cause has to be too much air getting into the engine getting into the engine and the ECU compensating for it.

My recommendation is to buy a smartphone app - "Torque" fit android or "OBD Fusion" for iOS - and the appropriate communications device (plugs into the obd2 port; the developer will state which device is needed) and record the "short term fuel trims" and "long term fuel trims." The apps will allow you to export the data as a csv (comma separated values) file. Excel will convert that into an Excel file. Then post the values here. Perhaps member jfoj can chime in.

Good luck.

[feels1]

Hi MarcoZandrini,


Thx for feedback.

I will capture "short term fuel trim" and "long term fuel trim" with Torque Android app, and share it.

I will post several scenarios
1. cold engine
2. warm engine (let it run from cold engine until it warms up in 10 min)
3. city drive with warm engine

More update to follow

[MarcoZandrini]

Sounds like the plan.

[feels1]

Hi MarzoZandrini,

It took me a few days to figure out how to configure Torque to log on Fuel Trims. I log this with cold engine. I uploaded into Google Docs as spreadsheet with following public link

https://docs.google.com/spreadsheets...it?usp=sharing

It contains ~ 7 min of log containing following data:

1. Time
   
2. Mass Air Flow Rate(g/s)
   
3. Fuel Trim Bank 1 Short Term(%)
   
4. Fuel Trim Bank 2 Short Term(%)
   
5. Fuel Trim Bank 1 Long Term(%)
   
6. Fuel Trim Bank 2 Long Term(%)
   
7. O2 Volts Bank 1 sensor 1(V)
   
8. O2 Volts Bank 1 sensor 2(V)
   
9. O2 Volts Bank 2 sensor 1(V)
   
10. O2 Volts Bank 2 sensor 2(V)
    

I assume you are using fuel trim short/long term to determine potential O2 sensor fault, so I am including O2 sensor voltage as well. MAF rate is added just in case

Kindly advise

[MarcoZandrini]

Your fuel trims are very high. That says the the ECU is trying to compensate for an anomaly. Let me download these to my desktop (I'm reading this on my iPhone) and really look at this. Also, I'm going to see if jfoj can give us some insights. He's very knowledgeable about these data.

[feels1]

Posting another spreadsheet from Torque log. I found that the previous one has 0 value in "Fuel Trim Bank 1 Long Term(%)"

This is a 1.4 hr log covering cold engine, ~1.4 hr drive and stop, and 30 sec of idle before I turn off the key (indirectly turn off OBDII connection)

Long term fuel trim in yesterday's log starts at 2.34% & 3.12% compare to 0% & 0.78% on Nov 20 (2 days ago).

In this log, I captured following so that you know about air temp, rpm, instant mpg (whether the car is moving)

1. Time
   
2. Mass Air Flow Rate(g/s)
   
3. Fuel Trim Bank 1 Short Term(%)
   
4. Fuel Trim Bank 2 Short Term(%)
   
5. Fuel Trim Bank 1 Long Term(%)
   
6. Fuel Trim Bank 2 Long Term(%)
   
7. O2 Volts Bank 1 sensor 1(V)
   
8. O2 Volts Bank 1 sensor 2(V)
   
9. O2 Volts Bank 2 sensor 1(V)
   
10. O2 Volts Bank 2 sensor 2(V)
11. Engine Coolant Temp
12. Intake Air Temp
13. mpg (instant)
14. RPM

https://docs.google.com/spreadsheets...it?usp=sharing

[MarcoZandrini]

I've asked jfoj, the resident guru, to check out your data.

[jfoj]

I will have to look the data over a bit more after Thanksgiving, but I would like to see the date with Vehicle Speed included.

I see the car is an Automatic, I assume this 900 RPM figure is while the car is in Drive?

I would make sure there is nothing causing the throttle to hang open a bit. The MAF reading appears to be a bit high which leads me to believe something is causing more air to be fed to the engine after the MAF.

Either the ICV is wrong, not closing enough or the throttle plate is hanging up a bit.

Each to check the throttle plate, split the upper and lower intake boot and with a flashlight look down the lower intake boot and make sure the throttle plate is actually fully closing.

Not sure why my PM box shows 100% full with only a single message on this forum, probably due to me not posting here too much??

Anyway, I will try to drop in and check on this thread later in the week.

[feels1]

The idle RPM of 700 - 800 (warm) or 800 - 900 (cold) is with Neutral gear position, not in Drive position. In second URL, I shown the mpg and RPM with cold engine. When mpg started to have higher than 0, that is with gear shifted to D. You can assume the rest of the time it is in D position, although I might occasionally shift to N on stop light.

[MarcoZandrini]

jfoj, the resident guru! You're in capable hands!

[jfoj]

What is the idle speed in gear when warm?

What are you using to determine the idle speed, car tach? OBDII tool? Do they agree?

700-800 RPM warm in Neutral sounds about correct, 800-900 RPM cold is not unusual.

So is there really a high idle problem here?

Until we have idle speeds in gear, it is pretty much irrelevant to discuss this.

[feels1]

Hi jfoj,

Thanks in advance for taking the time to help

I captured another log today with speed, RPM, fuel trim, O2 voltage, intake air temp

Capturing description:
1. Cars start in cold weather of ~ 1 °C
2. Car has been sitting idle for 9 hr prior of startup
3. Engine Coolant Temperature(°C) captured by Torque is about 10°C higher
4. Intake Air Temperature(°C) captured by Torque is about 10°C higher, but about right after row 3001
5. RPM from Torque match/agree car's tach
6. Car speed from Torque match/agree car's speedometer
7. Following link contains 4 min of idle
8. Whenever the approaching red traffic light (car speed 0), gear shifted to Neutral gear so that the log will capture as much warm Idle RPM as possible
9. Data is captured every 1 sec

https://docs.google.com/spreadsheets...it?usp=sharing

I captured following data in this log:

1. Time
2. Engine RPM(rpm)
3. Speed (OBD)(km/h)
4. Engine Coolant Temperature(°C)
5. Fuel Trim - Short Term(%)
6. Fuel Trim - Long Term(%)
7. O2 Volts sensor 1(V)
8. Mass Air Flow Rate(g/s)
9. Intake Air Temperature(°C)
10. Miles Per Gallon(Instant)(mpg)

In replying to your questions:
1. Warm in Neutral of 700 - 800 is more like 770 - 850
2. Cold in Neutral of 800 - 900 is more like 880 - 1100

I will capture another log tomorrow with longer time in Idle RPM with cold engine until warm engine. I would like to ensure to other readers/helpers that it does has a 100 - 150 higher RPM than spec.

When the engine is warm, when I shift to D gear, the car is rushing forward as the gas pedal is press a little (to give an equivalent of 780 RPM). Similar behavior is experiencing when I press brake pedal to full stop, the car is always takes a little more "braking force" to hold back. When let go the brake pedal, and it is immediately charging forward (mild).

[feels1]

Captured another log from Torque this morning with cold engine. This is a 15 min log, with fan off, seat heater off, etc. The only thing on is radio. Outside temperature is 1 °C, which means Engine Coolant Temperature and Intake Air Temperature are +7 higher than actual.

https://docs.google.com/spreadsheets...it?usp=sharing

Data captured:
I captured following data in this log:

1. Time
2. Engine RPM(rpm)
3. Speed (OBD)(km/h)
4. Engine Coolant Temperature(°C)
5. Fuel Trim - Short Term(%)
6. Fuel Trim - Long Term(%)
7. O2 Volts sensor 1(V)
8. Mass Air Flow Rate(g/s)
9. Intake Air Temperature(°C)
10. Miles Per Gallon(Instant)(mpg)

Additional info:
1. Car is sitting idle, with gear in Neutral in the entire 15 min, so Speed is 0 in the entire log
2. O2 sensor voltage is empty for unknown reason, but automatically captured much later by itself
3. RPM dropped from 1100 to 786 after ~ 15 min. This is what I indicated earlier that typical warm engine is 770 - 850
4. Car never put into D or R in the entire 15 min to avoid adding other noise/questions into the log

Tell me if you need me to capture additional data in order to analyze

[jarrett101]

Captured another log from Torque this morning with cold engine. This is a 15 min log, with fan off, seat heater off, etc. The only thing on is radio. Outside temperature is 1 °C, which means Engine Coolant Temperature and Intake Air Temperature are +7 higher than actual.

https://docs.google.com/spreadsheets...it?usp=sharing

Data captured:
I captured following data in this log:

1. Time
2. Engine RPM(rpm)
3. Speed (OBD)(km/h)
4. Engine Coolant Temperature(°C)
5. Fuel Trim - Short Term(%)
6. Fuel Trim - Long Term(%)
7. O2 Volts sensor 1(V)
8. Mass Air Flow Rate(g/s)
9. Intake Air Temperature(°C)
10. Miles Per Gallon(Instant)(mpg)

Additional info:
1. Car is sitting idle, with gear in Neutral in the entire 15 min, so Speed is 0 in the entire log
2. O2 sensor voltage is empty for unknown reason, but automatically captured much later by itself
3. RPM dropped from 1100 to 786 after ~ 15 min. This is what I indicated earlier that typical warm engine is 770 - 850
4. Car never put into D or R in the entire 15 min to avoid adding other noise/questions into the log

Tell me if you need me to capture additional data in order to analyze

What was the problem?

[feels1]

Hi jarrett101,

The root cause is still unknown. Car continue to be idling at high 700 - 900 rpm for years.

Replaced all the vacuum hoses at back of the engine block, CCV, high + lower intake boot, fuel pump, fuel filter, and the long list I posted in 2014-11-10.

If the situation changed, then I might update the forum.

[Bimmerfan84]

Hey feels1, did you ever replace the cam and crank sensors on this car? Just had this problem and found that an aftermarket intake cam sensor was the problem.

[feels1]

Hey feels1, did you ever replace the cam and crank sensors on this car? Just had this problem and found that an aftermarket intake cam sensor was the problem.

Hi Bimmerfan84,

There is no CEL which typically appears for both cam and crank position sensors.

Few months ago I replaced guibo (minor spider cracked, but still intact) and CSB (central support bearing - rubber detached), and hope it was related, but RPM still hovering ~ 800, with occasionally (< 2 sec) touching 780 rpm. Minor improvement.

Both cam and crank sensors are original (18 yr old), and high idle was there since I got it when it was 13 yr old.

I no longer has a computer with INPA software. I will need to install my INPA again, as I install Hackintosh in that laptop, and need to source another one.

Thank you for the input.

[2JZ E36]

Did you replace the water temperature sensor for the ecu? Water temperature is the main factor on which the ecu sets the idle speed.

[Arabuli]

Hello, i have too 330ci. Can you tell me, What do you do about this problem?I have the same problem.thank