Roomster hot start issues- Help please

[Jannercornwall]

Hi all from Cornwall. 

 

My wife runs her Skoda Roomster daily for work etc but we have a problem with it hot starting, oe lack of it !!!

 

I have done a full service inc all filters etc. Car pulls really well , it is the 3 cylinder tdi model 1.4 I think. From cold it starts really well and easily but after a run to the shops etc it is a sod to re start. The mot station plugged in their obd reader and they came back with three faults. Those being  19463- Cam sensor no signal    16485-  Mass air flow sensor implausible signal.  19587- EGR system regulatory range . 

 

I have cleaned the MAF sensor as per the usual methods. Cleaned the EGR as it was chucked with soot and carbon and fitted EGR blanking plate while in there. And the last two nights fitted a cam sensor twice and thats where the problems really start. Both new cam sensors when fitted means the car will not start at all but as soon as I plug the old (Faulty) one back in it starts easily even when warm, but hot starting is the problem. 

 

Can anyone please advise what the hell is going on here as we are off on holiday soon and the Engine management light is on and I want the hot start issue fixed as we are going a pretty long way from home . 

 

I don't have an obd reader so need sound advice on what a home mechanic can do. 

 

Thanks in advance all

 

Jon

[SuperbTWM]

The faulty sensor may work because if it is totally knackered then the ECU maybe ignoring the values and just going off the crank sensor, now you have tried a new, working one, there may be an underlying issue with the timing maybe so that's something you can do.

Edited 26 July, 2018 by SuperbTWM

[Jannercornwall]

1 minute ago, SuperbTWM said:

The faulty sensor may work because if it is totally knackered then the ECU maybe ignoring the values and just going off the crank sensor, now you have tried a new, working one, there may be an underlying issue with the timing maybe? 

Thanks for the quick reply . But surely if the timing was out the engine wouldn't be pulling so well and firing on half a turn of the key from cold or warm ? It's only when hot the issue is a problem !!

[Jannercornwall]

The more I'm reading up on this issue the more it points to a faulty CTS more than anything else or low battery voltage when hot thus resulting in too low a revs to start and inject fuel when hot ! 

[SuperbTWM]

There could be more than one issue here so you need to fix the faults you know about first, if you fix the cam position sensor and the maf the other problems may go away.

 

I'm not saying your timing is out but it costs nothing to check and in the world of fault finding you have to start somewhere and this includes ruling out things that may be unlikely but still could possibly cause an issue. 

 

Like you said above, CTS is also an easy test but you really need to see live data from the ECU with VCDS or scan tool.

 

Also, poor starters were common on some generations of 1.9 PD that caused hot start issues, so yes, a bad earth, battery, or starter will cause hot start issues too

Edited 26 July, 2018 by SuperbTWM

[Jannercornwall]

10 minutes ago, SuperbTWM said:

There could be more than one issue here so you need to fix the faults you know about first, if you fix the cam position sensor and the maf the other problems may go away.

 

I'm not saying your timing is out but it costs nothing to check and in the world of fault finding you have to start somewhere and this includes ruling out things that may be unlikely but still could possibly cause an issue. 

 

Like you said above, CTS is also an easy test but you really need to see live data from the ECU with VCDS or scan tool.

 

Also, poor starters were common on some generations of 1.9 PD that caused hot start issues, so yes, a bad earth, battery, or starter will cause hot start issues too

This is the 1.4 PD lump 3 pot tdi . Lovely engine and sings away great and pulls really well