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chasw7
14-03-2007, 11:47 AM
Hello forum,

I recently experienced loss of power in my 1.8t at various random points throughout the rev range. At approx 2200rpm, 3800rpm and 4100rpm the power just seemed to be showing huge flat spots. I told Volkswagen, Edinburgh Fort Kinnaird, which they then tried to diagnose.

After time in there garage, they told me to replace the coolant temp sensor/switch. I did this at my local garage to save costs, no change in the symptoms.

I went back to VW and they admitted a mistake, that they forgot to tell me of various faults when my ecu was checked - huge blunder which they have now rectified/refunded after various phone calls and meetings. The faults were:
P1200 - Recirculating valve for turbocharger - N249: mechanical malfunction
P1297 - Connection charger throttle valve - Pressure drop

I also had a diagnostics machine plug into my car at various other garages which all came back with,
P1200 - recirculating valve. Unfortunatley these machines also told me of another fault which the volkwsagen diagnostics machine did not pick up.
P1128 - Bank 1 mixture adaption (mult):system too lean.

I have been told by my local mechanic at John Hastie and Son of Prestonpans (A reputable garage which I trust a hell of a lot more than official VW at Fort Kinnaird), that the Bank 1 P1128 fault is an o2 sensor.

I have changed the recirculating valve for a brand new one, however the problem still exists, and, if anything, has become worse!! I have not replaced the o2 sensor yet purely because the official VW diag machine did not pick up the fault.

Any help at all would be very much appreciated. I have read pages and pages on these faults but I cannot come to any conclusion. I now need a true VW turbo expert!

The car is booked in at VW Fort Kinnaird Edinburgh for Thursday 15 March for a two hour diagnostics check/test. I sure hope they can diagnose the problem after another two hours working on my car. It would be nice to take some information to the mechanics at VW regarding this problem. Any help, info or resolved troubles in the past regarding this problem, please post here!!!!!! This car is costing me an arm and a leg. I got a VW because I wanted an affordable but well built car! Im not sure I have done the right thing getting a VW.......

Cheers,
Chas W

p.s The car idles very rough, and sometimes chooses to idle at 600rpm, other times it idles at 1200rpm on cold startup then drops to 800rpm when warm.

When the car is static, but running, you can feel a slight rough shudder in the car when reving between 2000rpm and 3200rpm.....very weird minging vibration!

The exhaust emmission light comes on the dash board approx 5hours after all fault codes have been wiped from the ecu. Could this suggest something to do with that bank1 o2 sensor?? Could this affect fuel mixtures? therefore the engine is running too lean, as stated by the ecu fault code? If so, why didnt the official VW machine pick up this fault?????

onzarob
14-03-2007, 01:43 PM
By o2 sensor i assume you mean lamda sensor, If it is faulty it can cause more faults to be logged.

The reason for this is the lamda probe is to measure how well the fuel is being burnt and adjusts timing and fuel delivery to acheive low emissions and fuel economy.

If you get the sensor changed then clear the codes you should find that the too lean error may also not re-appear.

Rob:D

chasw7
14-03-2007, 02:18 PM
Hi Rob, yeah, Im sure it is the lamda sensor. As far as I am aware, there is 2 o2/lambda sensors. Im not sure which one is broken, however I do know that the ecu refers to the broken sensor as 'Bank 1'.

The sensor is about £100. Hopefully this is where my problem is, Im spenging loads on diagnosis. Hopefully it the sensor broken and not something bigger which is making the sensor read wrong.
The car is booked in 2moro, I will mention to the mechanic to check the lamda's before he starts anything else.

Cheers for the info, I will tell the mechanics and Ille keep the forum posted.

The lamda sensor problem only appears on the dash after 5 hours of driving with no change in drivabillity. Bad drivabillity all the time, regardless of what lights are on the dash. shan. I just want to be able to wind up the turbo and get full power.......all the time! This sporadic behaviour is bloody annoying..........and expensive!

onzarob
14-03-2007, 02:31 PM
This is the falut code I read on a 2.0 skoda this week. i'm expecting the other codes to not reapper once the probe has been changed.

5 Faults Found:
16518 - Oxygen (Lambda) Sensor B1 S1: No Activity
P0134 - 35-10 - - - Intermittent
16555 - Fuel Trim; Bank 1: System Too Lean
P0171 - 35-00 - Please Register/Activate
16684 - Random/Multiple Cylinder Misfire Detected
P0300 - 35-10 - - Intermittent
16687 - Cylinder 3 Misfire Detected
P0303 - 35-10 - - - Intermittent
17536 - Fuel Trim; Bank 1 (Mult): System too Lean
P1128 - 35-00 - Please Register/Activate

I use the freeware version of VAG-com on my laptop and cheap cable from ebay.

find software here www.ross-tech.com (http://www.ross-tech.com)
find cable here www.gendan.co.uk (http://www.gendan.co.uk)

worth the money if you look how much it cost just to get the codes read.

Rob:D

chasw7
14-03-2007, 02:54 PM
Yeah, I need to buy the cable and the software required. Cheers for the links man.

I just spoke to Falkland Performance and they say that it could be an airflow meter and that it is unlikely it is a lamda sensor. That is obviously diagnosis over the phone. They will see the car on friday when the suspension gets fitted and Im sure they will be able to tell me exactly what is wrong!!!!

I am going to go ahead with 2moro's diagnosis from official VW and see what they come up with. I supposse this is their chance to redeem themselves and prove that their opinion is worthy of attention!!

Cheers,
Chas W

I havnt had any misfire fault codes!!!! It certainly feels like its mis-firing sometimes. If you rub your finger in the exhaust you find there is a funny oily black residue rather than what I would have expected, dry fumey typical exhaust smog!

chasw7
15-03-2007, 03:36 PM
Just got car back from VW, Edinburgh. It's fixed!!!!!! Thank god!!

VW replaced the air mass meter and the dump valve.

Credit to VW for finally working out my problem, and total credit to Kevin at Falkland Performance, Glenrothes, Scotland for managing to diagnose my problem over the phone. I must add, Ian at VW, fort kinnaird, edinburgh is very very good at his job and really knows his stuff.

In total I have spent nearly £400 fixing this fault. It could have been only £180 if I didnt have to pay for wrong diagnosis.........thank god I didnt replace th lamda sensor, eh rob??

cheers again,
chas w

onzarob
15-03-2007, 05:02 PM
Great you've got it fixed, Proves a point that the codes are a fault finding tool and not always a exact reason for the problem.

Now are you going to get a fault code reader which will save you a fortune;)

Rob:D

thepurple1
15-03-2007, 09:45 PM
I had the same kind of symptoms with my 2004 Bora TDI 130, it turned out to be the turbo, luckily this was replaced under the warranty. The fault was very hard to find as there was not always a fault code and power loss was intermitant it took three attempts by the VW dealer to diagnose