2006 Corsa Idling at 500rpm stumped for ideas

[foy12345]

Hi all,

My partners car has recently developed a low idle sitting around 500rpm. Over the last few months we have tried: changing the air filter, cleaning the MAF sensor (which increased the idle around 50rpm), checking for a vacuum leak and trying a second hand throttle body and throttle position sensor all with no success. The only indication of what could be causing this was was when we un-clipped the throttle position sensor pigtail which increased the idle to 950rpm, which is what have us the idea of changing out the throttle body and throttle position sensor but again this did not work.

Any suggestions will be appreciated, were both learning as we go but love working on cars!

Thanks!

James.

[paintman]

Diagnostic & see what is shown. I would suggest a tool that's Vauxhall specific rather than a cheapie generic code reader.

You MIGHT solve it by changing parts at random but you're more likely to empty your wallet to no effect.

[foy12345]

Thank you for replying!

I have got a decent one that reads codes and monitors performance, and I have checked that there is no codes being generated. In regards to the diagnostics monitoring is there anything in particular that we should be paying close attention to while the car is idling?

[Chris32345]

Lamba sensor's reading correctly?
If they are miles off engine could be struggling to run
Try un plugging then see if it changes anything

[foy12345]

Hello all,

I posted a month or two ago on piston heads about a low idling issue with my partners Corsa C 1.2 Twinport. I explained that we had changed the throttle body, cleaned the mass airflow sensor however this had no affect. I was advised by others on the forum to get a scanning tool that can pull information about the cars performance, which is what we did. As can be seen with the data below there was a few things that stood out to me mainly the desired Idle speed, I did reset this however it just stayed the same. I have never really analysed car data before and I was wondering if anyone can see anything below that stands out as majorly incorrect that could be causing this low idle.

Thank you all for your help.

James.


Measuring blocks information:

Battery Voltage 14.3 V
Main Relay Active
Fuel Pump Relay Active
APP Sensor 1 (Accelerator Pedal Position) 0.97 V
APP Sensor 2 (Accelerator Pedal Position) 0.49 V
Calculated Pedal Position 0%
APP at Idle Position (Accelerator Pedal Position) Active
TP Sensor 1 (Throttle Position) 0.80 V
TP Sensor 2 (Throttle Position) 4.31 V
Calculated Throttle Position 3%
Throttle Position Idle
Engine Speed 714 RPM
Desired Idle Speed 730 RPM
Mass Air Flow Sensor 1.39 V
Mass Air Flow Sensor 7 kg/h
Coolant Temperature 1.38 V
Coolant Temperature 75 °C
Intake Air Temperature 3.12 V
Intake Air Temperature 30 °C
Port Deactivation Position Sensor 2.8 V
A/C Information Switch (Air Conditioning) Not Programmed
A/C Pressure (Air Conditioning) 0.00 V
A/C Pressure (Air Conditioning) 0 kPa
Tank Sensor 1.94 V
Tank Sensor 24 L
Brake Switch 1 Inactive
Brake Switch 2 Inactive
Clutch Switch Not Programmed
Vehicle Speed 0 km/h
EGR Valve (Exhaust-Gas Recirculation) Inactive
EGR Position Feedback (Exhaust Gas Recirculation) 0.76 V
Fuel Tank Ventilation Valve Active
Knock Control Inactive
B1S1 O2 Sensor Heater (Bank 1 Sensor 1) Inactive
B1S1 O2 Sensor (Bank 1 Sensor 1) 156 mV
B1S1 Air/Fuel Ratio (Bank 1 Sensor 1) Lean
B1S2 O2 Sensor Heater (Bank 1 Sensor 2) Inactive
B1S2 O2 Sensor (Bank 1 Sensor 2) 451 mV
B1S2 Air/Fuel Ratio (Bank 1 Sensor 2) Rich
B1 Long Term Fuel Trim (Bank 1) -2%
B1 Short Term Fuel Trim (Bank 1) -2%
O2 Sensor Loop Closed
A/C Relay (Air Conditioning) Not Programmed
A/C Cutoff Mode (Air Conditioning) Underpressure
Cruise Control Not Programmed
Cruise Control Tip Switch Not Programmed
Vehicle Speed in Cruise Control Range Not Programmed
Malfunction Indicator (MI) Off
Service Vehicle Soon (SVS) Indicator Off
Oil Pressure Underpressure
Remaining Oil Life 87%
Engine Oil Change Warning Inactive
Ignition Status On 12V
Throttle Position PWM Servo Signal 14%
TP Sensor 1 Learned Lower Position (Throttle Position) 0.70 V
Engine Speed 1429 RPM
Injector Time 3.3 ms
Ignition Dwell Angle 1.6 ms
Ignition Spark Angle 10.7 °CA
B1 Knock Sensor Signal (Bank 1) 0.6 mV
Knock Retard Cylinder 1 0 °CA
Knock Retard Cylinder 2 0 °CA
Knock Retard Cylinder 3 0 °CA
Knock Retard Cylinder 4 0 °CA
Normal Engine Operating Temperature Inactive
Fan Control 1 Inactive
Fan Control 2 Inactive
Fan Control 3 Inactive
Deceleration Fuel Cutoff Inactive
Vehicle Acceleration 0 m/s2
Full Load Enrichment Inactive
Catalyst Protection Enrichment (Bank 1) Inactive
ETC Limp Home Mode (Electronic Throttle Control) Inactive
Electronic Throttle Control Learn Counter 11
Vehicle Speed Pulse Not Received
Immobiliser Function Programmed Yes
Security Wait Time Inactive
BCM: Vehicle-ID is programmed (Body Control Module) Yes
Instrument: Vehicle-ID is programmed Yes
BCM: Status of Vehicle-ID (Body Control Module) Okay
Instrument: Status of Vehicle-ID Okay

[GreenV8S]

You said it was idling at 500 rpm but the data you posted shows Engine Speed 714 RPM / Desired Idle Speed 730 RPM. That suggests it's idling a lot higher than you thought and quite close to the target speed. Is it possible the tacho is mis-reading and causing you to worry over a non-problem? If it's an analogue gauge it would be easy for it to give a bad reading.

[foy12345]

Hi,

Thank you for replying! and yes this is something we discussed as on the dash it still indicates 550rpm in idle. However, when we let the clutch out it often stalls and you really have to baby it.


I'm not sure if anything looks off to your in the data provided?


If not, no worries and thank you for taking the time to reply!

James.