Fuel trim

[paullap]

evap

Thanks, Ill give it a go today.

[David Green]

Paul,

Do a systematic check of the following, which should lead you to the cure;

17519/P1111 Oxygen sensor control; Bank 1: System too lean

Possible Causes

Mass Air Flow Sensors (G70) faulty
Intake Air System faulty/leaking (false Air)
Fuel Injector(s) faulty
Insufficient Fuel Delivery
Exhaust System leaking
Faulty O2 Sensor(s)

Possible Solutions

Check Mass Air Flow Sensors (G70)
Check Intake Air System for Leaks
Check Fuel Injector(s)
Check Fuel Delivery Including Pump and Filter
Check Exhaust System for Leaks
Check O2 Sensor(s) Adaptation Values (Before Clearing Faults: Fuel Trim Information)

[paullap]

p1111

I have taken the throttle body of and give it a good clean, I made a bug and put it on the intake where the throttle body goes, filled the intake with smoke, and the blew through a tube attached to the bung to pressure the system, No smoke coming out. And also it keeps its pressure for a good while. so if it had a leak it must be small. I have cleared the fault so many times, I think I will do the evap disconnection test, and then take it for a drive, and see if i get any more faults, I have swapped the map sensor, but the 02 is a wide band 5 wire £130. do you think I could put a scope on it to see what is happening, if so how do i find out which wire to connect to?.

Paul

[David Green]

Send me a pm of your full chassis number and registration number.

[David Green]

Paul, here is a link to show how to test your wideband oxygen sensor.

Make sure all engine sensors are working correctly before diagnosing this sensor faulty.

https://www.picoauto.com/library/training/testing-the-bosch-lsu-4-2-broadband-oxygen-sensor

[paullap]

fuel trim

Wow, that is a lot of testing for one sensor, not sure how to do the breakout leads, surely I could back probe the connection block. There is not many other sensors on it, map/temp sensor, knock sensor( probably not going to affect anything, Temp sensor. Do you have anything on testing the map/temp sensor?.


Many thanks for your help.


Paul

[Witsend]

O2 sensor definitely would have to cost more than a few hundred dollars and car have less than 100k on the odometer for this Lambda D@mnda Ding Dong to pull out a scope for the Tri Beta Cr@ppa.

[David Green]

Wow, that is a lot of testing for one sensor, not sure how to do the breakout leads, surely I could back probe the connection block. There is not many other sensors on it, map/temp sensor, knock sensor( probably not going to affect anything, Temp sensor. Do you have anything on testing the map/temp sensor?.


Many thanks for your help.


Paul

Don't jump to conclusions without a good understanding of what the sensors are actually telling the PCM, and what the PCM monitors are doing with those sensor input signals.

During warm up the engine temperature sensor does have an influence on PCM behavior, ensure the sensor works correctly during the warm up phase, e.g. no drop outs in the voltage trace and the sensor is actually working within the correct operating parameters.

Ensure also the IAT sensor is working correctly (MAF), this can normally be checked using an ohm meter and breathing on the air sensor or use a hair dryer if necessary, carefully. Fueling corrections are completed by the PCM based on this signal.

The ECT is over ridden in operation when the exhaust lambda temperature reaches something like 950 degrees C (Check data on that).

The important's of sensor input signals should not be over looked during a diagnostic procedure, if in doubt use the following procedure;

1 / Verify - Check the fault is as described
2 / Collect - Ensure you understand the function and operation of the systems, components etc.
3 / Evaluate - stop and think about the fault logically
4 / Test - Measure and compare your results to manufacturer recommendations.
5 / Rectify - Fix the fault, if necessary replace parts
6 / Check - Make sure the system works correctly and other systems have not been affected by what you have completed.

Road test the vehicle and let any monitors run their drive cycles, try to ensure they are complete and not other pending/fault codes have returned.

[paullap]

02 sensor

Hi David, Thanks for the info, That Pico testing sheet has 6 wires, I am quite certain I have 5 wires?.


Paul

[David Green]

Hi David, Thanks for the info, That Pico testing sheet has 6 wires, I am quite certain I have 5 wires?.


Paul

The wiring diagram for your sensor shows 6

[paullap]

fuel trim

Mine definitely has 5 wires

Blue
Black
Yellow
White
Grey


pt number VW AG 036 906 262 T



engine is a BKY engine


I have that Wiring diagram from autodata, and that shows 6 wires as well
so I am not sure what is going on.


Paul

[David Green]

Paul at this point given that you have access to Autodata they do have a help line when you log in, they have a very fast turnaround and will source you another diagram. They are very helpful people.

[paullap]

fuel trim

Good idea, Ill do it now.

Thanks

[paullap]

This is the reply from autodata Jamie (Autodata Ltd)

Aug 3, 13:48 BST

Good afternoon,
VW as a manufacturer have only produced two diagrams for this model and engine variant, both of which show 6 wires. We only get our information for everything on the system directly from the manufacturer, if they have chosen not to publish a matching diagram when you chassis number has been used (which should provide a perfect match) then there is nothing more we are able to do.
Regards

Jamie Willis
Senior Technical Support

[paullap]

I have now put the throttle body back on and drove the car, It drove great for about 5 minutes, I went round a bend and it nearly cut ou, t it would not go properly for about 100 yards, Then it got a lot better, I have just ordered a fuel filter. and I then will try it again.



Paul