Help With P1171 Error On 2.2 Sc

Shamone

Hi can anyone help? (I've also posted this on VX220.org in case any of you are members there).

I have a 2.2 that was supercharged by Courtney last summer. After a few drive belt hiccups I never really got to drive it much before winter set in.

Now the good weather's here it's been out a few times but I've found that the fan keeps coming on despite the temperature being well below the 104 degrees. I investigated further, after purchasing Gendan software and ELM327 Bluetooth interface, and found error P1171 active in the engine management data. As soon as I clear the code the fan goes off immediately.

I've done a search and found: P1171 - Fuel Supply System Lean During Power Enrichment.

I have captured the freeze frame data that was recorded shown below:

Calculated Load 27.06 %
Coolant Temperature 86. C
Short Term Fuel Trim Bank 1 7.81 %
Long Term Fuel Trim Bank 1 0. %
Intake Manifold Pressure 38 kPa
Engine Speed 2063 rpm
Vehicle Speed 65 km/h
Ignition Timing Advance 16. Âº
Intake Air Temperature 15. ÂºC
Oxygen Sensor 2 - Bank 1 voltage
Oxygen Sensor 3 - Bank 1 voltage 0. V
Oxygen Sensor 4 - Bank 1 voltage
Fuel System 1 Status Open Loop (accelerating)

I think it may have been caused by the upgrade, so am hoping someone out there with an SC has seen the same fault and fixed it.

Fingers crossed, Cheers Simon

MikeS

open loop is not good

it needs to be in closed loop after about a minute

been advised by vauxhall that code is not lambda specific

it is either the fuel pump / ecu relay or ecu

Shamone

After reading my Engine Management Manual it says that under full acceleration it should go open loop, and only be closed loop at idle and during light throttle openings.

MikeS

oki let me explain

open loop cold start means that the ecu uses like a template of your sensor readings whilst your lambda's hit a certain temperature

closed loop is when lambdas hit 600 degrees F and the ecu actually takes readings from map / maf / both lambdas / cts to optimize fueling

so simply closed loop means all sensors are working correctly and are outputing within a desired range

open loop means the the ecu is not using sensors to control fuel / air mixtures

based on your freeze frame data there aint much to go on

i need to a see a graph of both lambdas

your long term fuel trim is 0% - might be your rear lambda is dead or unplugged from harness in engine bay, cant see it being 0% at 2000 revs

as for your fan suggest seeing whether your coolant temp sensor is plugged in as i know they control the fan on the z22se

Shamone

Hi, got the following info from Gendan:

Open loop
The normal condition while the oxygen/lambda
sensors are warming up. The engine is
‘ignoring’ the output from the oxygen/lambda
sensors, until the sensors reach operating
temperature.

**Closed loop **
The normal condition once the oxygen/lambda
sensors have reached operating temperature.
The engine is using the output from the
oxygen/lambda sensors to control the fuelling.

Open loop(accelerating)
The car is not using the output from the
oxygen/lambda sensors while the car is
accelerating.

Closed loop(system fault)
The car is in closed loop, but it has detected a
fault with the oxygen/lambda sensor.

Open loop(system fault)
The car is not able to go into Closed Loop
because it has detected a fault with the
oxygen/lambda sensors.

I think open loop accelerating is normal when I've got my foot down.

The long term fuel trim is 0%. Could this be because I pulled the fuse for the ECU to clear the data - I have only done 50miles since?

vocky

according to the vx220 TIS

P1171 Fuel System Lean During Acceleration

The control unit recognises the malfunction of the circuit via an internal evaluation logic.

Fuel Pump Circuit - check relay K18

Shamone

Hi Vocky,

funnily enough I pulled that relay at lunchtime today and connected it to a 12v supply. I measured the resitance on the normally open and normally closed sides and both were 0.1 ohm (my leads resistance).

Cheers Simon

Shamone

Hi,

Jon from Courtney rang me this morning.

They have seen the problem before on Supercharger conversions. The mixture is only lean when the engine is cold under very slight throttle openings. It's competely down to the mapping and should be resolved soon 😃 Just have to warm the car slightly before driving in the mean time.

Thanks for the advice, Simon