VW Polo 1.2 3cyl timing chain

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LEYLAND MILL MOTORS
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VW Polo 1.2 3cyl timing chain

Post by LEYLAND MILL MOTORS »

Hello all
We have VW Polo 1.2 3clynder with suspected stretched timing chain

Vehicle has a fault code P0171 system too lean bank 1

Enclosed is a saved cam shaft and crank shaft attachment file

Channel 3 is just a trigger from No.1 cylinder ignition coil

When the vertical cursers are lined up, as in frame 32.
When I scroll back through the frames the edge's should be in line every time?
We see left hand vertical is not inline in each frame on the crank shaft vertical, this is suggesting a stretched timing chain?

Thanks for any input
Steven
Attachments
Volkswagen_Polo_2008_Petrol_20150903-0002.psdata
(5.15 MiB) Downloaded 1394 times

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Robski
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Re: VW Polo 1.2 3cyl timing chain

Post by Robski »

CMP/CKP for a P0171 :?:

What tests have you carried out :?:

FT's/MVB's etc :?:

LEYLAND MILL MOTORS
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Re: VW Polo 1.2 3cyl timing chain

Post by LEYLAND MILL MOTORS »

Thank you for the reply Robski

The vehicle came to us from a dealer who sold it and customer brought it back with engine lamp on.

They read the codes, P0171 and replace the upstream O2 sensor with an aftermarket NGK

A week or so later vehicle was referred to us, lamp on dash and no driveability issues.

Reading codes and looking at live data LTFT was high (using snap on in OBD), we smoke tested it to find inlet manifold gasket leaking along with vacuum pipe to servo leaking and rubber perished.
All other checks appeared ok.

The dealer took car away, replaced gasket and pipe and returned vehicle to customer.

Vehicle then came back again with same code P0171 beginning of last week.

I had a look at live data and all looked ok (forgot to save data again)

Yesterday I thought I would check a few basics and cam/crank synchronization, ( we have replaced a couple of noisy chains on these)

I noticed the manifold pressure reading on acceleration, would drop and then recover, removing and cleaning the oil covered sensor gave a better consistant live data reading.
The P0171 comes on as soon as test drive but dose not bring lamp on dash

That's when I saved and posted file yesterday, with the same thought of how can cam/crank cause P0171?

I will re do the tests again and post over the week end

Thanks again
Steven

KimAndersen
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Re: VW Polo 1.2 3cyl timing chain

Post by KimAndersen »

You still have multiple diagnostic opportunities to find the cause to the diagnostic trouble code P0171.

Have you checked the fuel pressure and the injectors !!!

There is also the risk of a exhaust leak near or around the oxygen sensor that could set this DTC P0171.

Regards
Kim

LEYLAND MILL MOTORS
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Re: VW Polo 1.2 3cyl timing chain

Post by LEYLAND MILL MOTORS »

Thanks for the reply Kim

I had another look today, and with vehicle stone cold from over night, I found a very small leak when I smoked the exhaust again.

Previous tested this when warm and no leak from joint

This leak was at the cat to down pipe flange just before the down stream O2 sensor. resealed the joint, reset all learned values, after a extended test drive the P0171 was back :cry:

STFT was +9% switching to 0% at idle.

I will do a fuel pressure test and injector voltage and amp measure in the morning.

Thanks again for the input
Steven

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Robski
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Re: VW Polo 1.2 3cyl timing chain

Post by Robski »

I will do a fuel pressure test and injector voltage and amp measure in the morning
Why ? Do you have any proof to send you in this direction ?
As for the latter part of the quote ................ just for fun ????? & in the morning :shock:

live data looked ok
OK ? is that how the PIDs are displayed or do you get actual numerical values ?

Either post some hard info like scan logs/graphs or captures relevant to a fuel trim code under different loads or............... :roll:

LEYLAND MILL MOTORS
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Re: VW Polo 1.2 3cyl timing chain

Post by LEYLAND MILL MOTORS »

Thanks for the reply
I Looked again the Polo this afternoon (joys of self employed along with no phones or customers calling on a Sunday afternoon.

Picture 1 is verdict screen vehicle stationary idling with a couple of WOT snaps at 50 & 80 seconds
The attachment polo screen shot 1.JPG is no longer available
pic 1
pic 1

Picture 2 is test drive
test drive
test drive
Picture 3 is a longer acceleration up hill
up hill
up hill
All the time the LTFT % was fixed at 0%

pending code after a couple of test drives, no engine lamp on dash

I did notice a couple of times on test drive a slight hesitation. I could not replicate this on demand
Attachments
pending code
pending code

LEYLAND MILL MOTORS
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Re: VW Polo 1.2 3cyl timing chain

Post by LEYLAND MILL MOTORS »

O2 sensor output and heater relative compression with trigger from coil no.1

LEYLAND MILL MOTORS
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Re: VW Polo 1.2 3cyl timing chain

Post by LEYLAND MILL MOTORS »

I seem to be unable to upload files
When I click add file, my post a reply screen then goes blank.
Am I doing something wrong?
Typed this all out about 4 times now

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Robski
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Re: VW Polo 1.2 3cyl timing chain

Post by Robski »

I would like to see both O2's, RPM & TPS @ WOT 3rd gear to redline.

Can't view PSD files on tablet, a screenshot of suspected area/s would be advantages to such.

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