VW Polo 1.2 3cyl timing chain

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VW Polo 1.2 3cyl timing chain

Postby LEYLAND MILL MOTORS » Thu Sep 03, 2015 7:19 pm

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 106 times
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Re: VW Polo 1.2 3cyl timing chain

Postby Robski » Thu Sep 03, 2015 8:18 pm

CMP/CKP for a P0171 :?:

What tests have you carried out :?:

FT's/MVB's etc :?:
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Re: VW Polo 1.2 3cyl timing chain

Postby LEYLAND MILL MOTORS » Fri Sep 04, 2015 9:08 am

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
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Re: VW Polo 1.2 3cyl timing chain

Postby KimAndersen » Sat Sep 05, 2015 8:13 am

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
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Re: VW Polo 1.2 3cyl timing chain

Postby LEYLAND MILL MOTORS » Sat Sep 05, 2015 9:26 pm

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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Re: VW Polo 1.2 3cyl timing chain

Postby Robski » Sat Sep 05, 2015 10:11 pm

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:
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Re: VW Polo 1.2 3cyl timing chain

Postby LEYLAND MILL MOTORS » Sun Sep 06, 2015 9:11 pm

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

polo screen shot 1.JPG
pic 1



Picture 2 is test drive
polo screen shot 2 test drive.JPG
test drive


Picture 3 is a longer acceleration up hill
polo test drive up hill.JPG
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
DCP_1188.JPG
pending code
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Re: VW Polo 1.2 3cyl timing chain

Postby LEYLAND MILL MOTORS » Sun Sep 06, 2015 9:19 pm

O2 sensor output and heater


relative compression with trigger from coil no.1
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Re: VW Polo 1.2 3cyl timing chain

Postby LEYLAND MILL MOTORS » Sun Sep 06, 2015 9:28 pm

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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Re: VW Polo 1.2 3cyl timing chain

Postby Robski » Sun Sep 06, 2015 9:33 pm

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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