CAXA VW 1.4 TSI Timing chain stretched?

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CAXA VW 1.4 TSI Timing chain stretched?

Postby Mclain » Mon Jul 04, 2016 2:44 pm

Hi All,

Tried to post this question a few hours back, but cant find it anymore.

Long story short, i had some training from Steve, and decided to save up for a Picoscope. The library is amazing, and as far as i had understood from the AMT Bootcamp, i only need a picoscope and an internet connection. But last week we got a call that we would get a car in the shop where we had to check the timing. So i thought, we can do this non evasive as Steve thought us. So i went online, bought myself a 3404B scope and hooked it up this morning.
Unfortunatly, i have no library acces, as this scope isnt an automotive one.
So i asked pico, and they cant help me, they stated however that i can ask you guys for help.

So i have this car:

VW Golf
2010 CAXA engine
1.4 TSI 122 BHP

Channel 1, Camshaft
Channel 2, Crankshaft

Between the rising edge from the missing tooth to the rising edge of the small camshaft signal, is 80 degrees. This is while the car is idleing.
When i take of the connector of the Variable Timing solenoid, it will stay the same. At that point the Snapon will tell me that the camshaft is at 19.5 Degrees timing.

Hopefully someone can help me out so this isnt a complete waste of time :P

Thank you guys alot.

Best regards

Michel
Attachments
CAXA Idle.jpg
CAXA Engine Idle Camshaftvs Crankshaft
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Re: CAXA VW 1.4 TSI Timing chain stretched?

Postby Fat Freddy » Mon Jul 04, 2016 11:09 pm

Hi Michel.

What codes, symptoms do you have?

Can you re post the image with a higher amplitude of the crank in the image?

I'd be interested to see a capture of the very first crank/attempted start of the day from KOEO to running after it has sat over night if possible?

HTH
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Re: CAXA VW 1.4 TSI Timing chain stretched?

Postby Mclain » Tue Jul 05, 2016 7:35 am

The car runs just fine and starts without hassle. Only thing i noticed was a dip in torque. Feels like the boost ramps up just a tad to high and the ecu reduces the boost accordingly. So it might be a result of a bad timing, or just in need of a recalibration.

It just gives a code:

p0016 Camshaft Position Sensor (G40) / Engine Speed Sensor (G28): Incorrect Correlation

As these are known for chain problems, we wanted to check the timing and see if there are abnormalities. if so, we will change the timing.
And if you ever worked on one of these, you know you only want to take him apart just once :P

So a comparison to a good timing one, would be enough to determine whether it is stretched/miss-timed of not
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Re: CAXA VW 1.4 TSI Timing chain stretched?

Postby clt » Tue Jul 05, 2016 4:38 pm

this is from a 1,4 tsi enginecode bmy. looks like the same patteren.
Attachments
timnggolf BMY.psdata
timing golf bmy
(12.84 MiB) Downloaded 51 times
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Re: CAXA VW 1.4 TSI Timing chain stretched?

Postby STC » Tue Jul 05, 2016 10:21 pm

From personal experience, I have seen these engines with the Cambelt a tooth out and they will not start throwing a correlation fault and "Engine start blocked by Immobiliser" Fault.

If the above stands true for your particular engine then I would guess that the correlation error only occurs after it has started and not present whilst cranking. Is that the case ?

Further to Freddie's suggestion, paralyse the VVT and look for Cam Signal swaying against the Crank.

Is there a Correlation PID in the data streams ? You could graph that alongside RPM and some others of choice to establish the exact moment it faulters, capture that on the scope.

I'd say you have a chain issue but you will want to find evidence before you pull it apart. As for your over boost theory, that can be proved or denied by scoping the actuator command and MAP sensor. I wonder if it is boosting correctly (overboost conditions on VAG throw fault codes for fun) at that point it faults and pulls it down into limp home ??

As for comparing your waveform to one from a different engine code and / or build date, don't do it !!! That could lead you up the garden path for hours. beg, borrow, steal a known good from the correct engine. Look for a SSP for that engine or log into Erwin if there is not one in the Library.
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Re: CAXA VW 1.4 TSI Timing chain stretched?

Postby clt » Wed Jul 06, 2016 7:47 pm

Here you go.
Attachments
359 - 1.4l TSI Engine with Dual-charging.pdf
(2.63 MiB) Downloaded 53 times
405 - 1.4l 90kW TSI Engine with Turbocharger.pdf
(2.46 MiB) Downloaded 54 times
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