Octavia non start

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DIESEL_DOCTOR
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Octavia non start

Post by DIESEL_DOCTOR » Sun Jan 21, 2018 8:55 am

Hi all, this is my first post and typically I assume like most looking for some input/guidance with a problem!!

We have a 2.0L Octavia Diesel (BKD) in with a non start issue, diagnostic equipment not reading crank signal.
When we've scoped the reference voltage and signal from the sensor, we seem to be loosing the signal voltage when the sensor is "on load" (forgive me if the terminology is a tad pants), as per the attached. We do also have a poor ground (or negative) to the sensor, but we have grounded this but still get the same trace.

In addition the reference voltage for the cam sensor is non existent when connected, i.e. we have 5V prior to connecting but nothing when connected.

Could I be so bold to ask for your thoughts please.

Thanks in advance
Nev :D
Attachments
OE06 UDT.jpg
Crank sensor supply and signal

liviu2004
TwoWaves
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Location: Netherlands

Re: Octavia non start

Post by liviu2004 » Sun Jan 21, 2018 8:59 pm

Short to ground on 5v reference voltage which goes to cam sensor. Start pulling the connectors for all sensors and actuators until your connected cam has 5V. Or maybe that cam sensor is shot.

Do you have wiring diagrams for me?

DIESEL_DOCTOR
Newbie
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Joined: Sun Jan 21, 2018 8:35 am

Re: Octavia non start

Post by DIESEL_DOCTOR » Sun Jan 21, 2018 9:43 pm

Thanks for the reply, diagram attached.
It would make sense that the cam sensor is shorted to ground, but even with it disconnected and with the 5v reference then present the signal on the crank remains the same?
Attachments
Wiring diagram _ Autodata.pdf
(355.68 KiB) Downloaded 66 times

liviu2004
TwoWaves
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Location: Netherlands

Re: Octavia non start

Post by liviu2004 » Mon Jan 22, 2018 9:25 am

I would not worry now about crank sensor. Fix the other obvious problem. I will check the diagram this evening and make a plan of attack.

grunf1976
OneWave
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Location: Belgrade, Serbia

Re: Octavia non start

Post by grunf1976 » Mon Jan 22, 2018 11:29 am

Hi,
what year is the car? on these cars when cam sensor dies it still starts but logs a fault code for it and it takes a longer cranking time . common problem on 2.0 for not starting is shorted injector. it shorts to ground. it is rare on BKD engines but worth checking because those are the symptoms.

liviu2004
TwoWaves
TwoWaves
Posts: 120
Joined: Sat Mar 19, 2016 8:23 am
Location: Netherlands

Re: Octavia non start

Post by liviu2004 » Mon Jan 22, 2018 6:31 pm

DIESEL_DOCTOR wrote:Thanks for the reply, diagram attached.
It would make sense that the cam sensor is shorted to ground, but even with it disconnected and with the 5v reference then present the signal on the crank remains the same?
Drawing is very hard to read, but from what I can tell, there is no way to know to which component the reference voltage goes. Follow the advice above me, cause I am not really into VW group.

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