hot start problem skoda octavia 1.9tdi 2009

skodabeast

New member
Joined
Jul 5, 2020
Location
ireland
TDI
skoda octavia 1.9tdi
Hello,
I am really really stuck on this now,4 wks ago my skoda octavia mk2 1.9tdi 2009 would not start when engine was hot,cold starts no problem whatsoever,since then i firstly changed fuel pump as i rushed into panic,did not work.
So after searching through forums and forums and some mechanics,i have since changed the coolant temp sensor,the crankshaft sensor,and on friday changed the starter motor and also the fuel filter.also had battery tested and tried to start when engine was warm with power pack,all through this if i disconnect the coolant temp sensor the car starts hot or cold but i know im only by passing the problem doing this and need to get to the bottom of it.
I am spending an absolute fortune and getting nowhere frown there is no fault codes coming up on diagnostic machine,the guy who done the starter on friday thinks it is the injector seals are worn and not getting enough compression to start when engine is hot,that all sounds real but my question is if it is the seals worn then how is it if im disconnecting the coolant temp sensor the car will start no problem,if the seals are the problem then why would disconnecting the sensor have any effect and would it not mean if the seals were the problem then the car will not start warm regardless of coolant switch been connected or disconnected?if there is a air gap created from worn seals surely that air gap will not suddenly seal if im disconnecting the coolant temp sensor?i can not afford to keep trying things and to be honest no sane person can keep pumping money into the car hoping the next fix will solve the problem,can someone please advise or help if have experienced this before ? Thank you for time to read big rant ,i dont think cutting wire looms and by passing the coolant sensor into tricking the ecu to think its cold starting is the answer,surely the underlying problem needs to be found?
 

Mozambiquer

Vendor , w/Business number
Joined
Mar 21, 2015
Location
Versailles Missouri
TDI
1998 VW Jetta TDI. 1982 VW Rabbit pickup, 2001 VW Jetta TDI
By your description, the first thing I would check would be timing. If it starts when you unplug the coolant temp sensor, that will fool the computer into thinking it is -40C, which will make it advance the timing.
If you connect with vag-com, you can check the torsion value while the engine is running. Let me know what that is, that will tell you a lot.

Sent from my S60 using Tapatalk
 

Divakaran

Member
Joined
Jul 6, 2021
Location
Chennai India
TDI
83 110 BHP SKODA Octavia Mk2
hi - can any one help by sharing your views and advice. me too have the same issue however i did not changed anything yet. i connected my VCDS and did a autoscan but unfortunately no errors. checked the fuel pressure from fuel tank, and the electric pump to HPP and all within limit.

the radiator fan and axillary fan is rotating all the time as soon as i switch on the key but not started. the batteries are fine, the starter motors are fine and health. it cranks healthy. the temperature meter in the instrument cluster is all the way right in red. can you please advise how to start the troubleshooting. i was thinking it could be the coolant temp sensor however technically it should not make the car dead. so please advise
 

Rx7145

Veteran Member
Joined
May 21, 2017
Location
Ohio
TDI
2006 Jetta BRM
What’s your torsion value? I would try moving it a little bit negative and see if that helps.
 

Divakaran

Member
Joined
Jul 6, 2021
Location
Chennai India
TDI
83 110 BHP SKODA Octavia Mk2
hi my car is using UDS protocol and i am not sure whether i can be able to find the torsion value? can you please help? my temperature needle in the dashboard is extreme right in red when i switch on the ignition and the radiator is started running. no error code in VCDS and battery are good, compression is good, fuses good. fuel pressure and flow is good. if i remove the coolant temperature sensors both G83 and G62, the temperature needle is coming to center however the car is still not starting. can you please help
 

Divakaran

Member
Joined
Jul 6, 2021
Location
Chennai India
TDI
83 110 BHP SKODA Octavia Mk2
Hi All good morning and hope all will have great plan for the weekend. I am back after a some medical situation, my car is having the same issue. the car is not starting, batter was flat and i changed it after charging. the VCDS is not showing any error however the car is not starting. initially the fuel pressure was 0 and i fixed it and have have correct flow and pressure as per factory manual. the compression is perfect and battery is perfect. so i removed the high pressure pump delivery to the injector distribution system and found not fuel is coming out. i though it could be HPP issue however its not. i removed the meter device from the high pressure pump to check if there any issue and i cranked the car without meter device on HPP to check whether the signals are coming. the car is started and running normal and if i connect the metering device back, the car is not starting? so does it mean the metering device is faulty or is there a way to check the meter device whether its working of faulty by multi meter or VCDS. VCDS is not giving any error. please help and your expert advice will be much appreciated. thanks and have a great weekend.
 
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