Car dies while driving

[Stephen McVarnock]

Folks,

I have a Skoda Octavia Silverline 1.6 petrol engine car that has been converted to run on LPG. Recently I have started having a major issue with the car and I am hoping that a few heads on here may have come across the same problem and can offer advice/suggestions.

Background

• On Monday past, the car went completely dead (loss of power steering, breaking becomes more difficult) after breaking hard. Engine warning light came on (running on petrol - car had only been running a few minutes)
  
• I had to turn off the wipers and lights in order for it to start up correctly - it struggled otherwise (petrol)
  
• The car stalled a couple of more times within 5 minutes of driving after that (petrol)
  
• About 1 hour later I noted that the car seemed to suffer a loss of power and started to shudder when driving at around 45 mph in 5th gear. It felt like she was about to stall even with the foot on the accelerator. It passed after 5-10 seconds. Had to drop down the gears. (running on LPG)
  
• I then noticed on the way home a noticeable loss of power when climbing up a moderately inclined road (LPG)
  
• The car displayed a lack of power the following day but only suffered one stall (LPG/petorl?)
  
• After that the car was fine for a few days
  
• On Sunday (today), the car stalled again while driving (the battery warning light coming on). This happened several times in quick succession (petrol)
  

The problem of the car going dead seems to happen while slowing down/breaking/while clutch is in going down through the gears.

• On letting out the clutch again the car engine seems to re-engage (as long as I am not fully stopped)
  
• We have checked the battery (which had only been replaced 2 months ago) and the voltage is within expected boundaries
  
• We have ruled out an altenator issue
  
• Visually checked the connections and visual inspection seems fine.
  
• Checked the air-inlet pipes and these seem fine.
  
• The problem does seem to be intermittent in nature
  

As I said, the car has been converted to run on LPG. I experienced similar problems when the car cut over from petrol to gas but that happened on really cold days during the bad winters a couple of years ago. That was resolved by increasing the cutover time to allow the engine to get warmer. I don't think this is the same problem.

I have however noted that the car does die if I manually go back from gas to petrol shortly after the automatic cutover. If the car is warm enough this does not happen. There is no issue going from petrol to gas though.

I have found a similar problem on the forums here:-

www.briskoda.net/forums/topic/136206-engine-dies-while-driving-then-starts-again/page__hl__+car +dies +while +driving#entry1707246

So the problem's root cause could be one of the following according to the above post:-

1. Fuel pump relay
   
2. Electrical short circuit
   
3. fuel sensor (not sure what was meant here - fuel pressure regulator I assume?)
   

However there were other suggestions that I found on other forums (non-skoda specific)

1. coil pack
   
2. air flow meter
   

So the question is has anyone else on here experienced this issue? How was it resolved? Can anyone suggest the best way to root cause the problem? Can anyone suggest the most likely candidate for the issue and in what order to clean/repair/replace the parts as described above i.e. go with the fuel pump relay first, followed by the coil pack.

All advice most greatly received!

Cheers,

Steve.

Edited 19 November, 2012 by Stephen McVarnock

[Stephen McVarnock]

Other suggestions include something called an idle air control valve which I have referenced on other forums but not here - so not even sure if such a part exists in the Skoda Octavia 1.6....but thought I would throw it into the mix.

Steve.

[Liverpool-Lad]

Did you check the ecu fault codes ?

[Philip Coulson]

I had an intermitant problem with my alternator that did some weird things like this. Only did it during wet weather so when I went out with a meter on a dry day all seemed fine. Was a dirty connection, just needed a squirt of wd40.

Worth investing in one of the code readers off ebay. It have helped me out on a number of occations.

[Stephen McVarnock]

There is a fault code (engine running rich/lean) - but this has been in place since the car was converted to LPG. So that won't help resolve this particular problem unfortunately. Not relevant to this particular problem unfortunately.

[Steven89]

Sounds like a weird situation .. Me personally I would clean the maf ( air flow meter ) with electrical cleaner if that doesent solve it I would Mark the coil packs left to right 1234 remove and clean with the electrical cleaner then take out the spark plugs clean or replace then re assemble and take for a drive ... Hope this helps

[Stephen McVarnock]

If no-one obects I'll keep adding (almost) daily updates - almost as a tracker for myself to see how the problem develops - or not.

The car this morning suffered no power loss at all. However one thing I did notice was that the car struggled for a few seconds shortly after start-up. This lasts a few seconds only. I have seen this previously. Before I had assumed a problem with the spark plugs which were replaced (and needed replaced!). I have, however seen this problem on occassion since then. Once again, this is intermittent in nature - and happens on the petrol.

Going to have another look today - all suggestions will be taken on board.

Rgds,

Steve.

[Lofty79]

Maybe check all the fuel pipes for leaks as it could be air in the system.

[Steven89]

Would there be any chance it's pulling in air through a loose fuel line ? Can you see any weeping from any joins in the fuel line or could it be the seals on the injectors if one has gone in twisted ?

[Stephen McVarnock]

Ok, so this morning the car started with no problem (see previous post). Having looked at all the info on the various forums decided to chek the MAF. Unplugged the MAF and the car ran without an issue, on plugging the MAF back in the car stalled immediately. Cleaned out the MAF - did not appear to be overly dirty. Car seemed fine after this. Also cleaned as many of the connectors/sensors we could see.

Came back later and started the car. Walked away to see how it would do idling would it died during idling. This was a first. Previously the car had only died while driving and slowing down. Started the car several times and experienced the same thing. In order to get past this I had to press on the accelerator - once the car was sufficiently warm it no longer died. It looks like the problem has been exacerbated by what we tried.

Did get several new codes up on the ECU though (as a result of cleaning connectors/sensors?)

http://engine-codes.com/p0172_volkswagen.html

http://engine-codes.com/p0322_volkswagen.html

http://engine-codes.com/p0335.html

This first one I have been getting since the car was converted to LPG and had been explained away by the installer of the LPG due to the difference in fuel mix required between petrol/LPG and air. Happy enough to accept it at the time. But this error also covers a faulty MAF sensor.

So what am I dealing with here? Is the culprit the MAF? Or am I looking at a multitude of sins that need fixing?!?!

[Steven89]

me personally id bite the bullet replace the maf however its just weighing up time trying to grasp the fault or spending a bit of cash to try eliminate the issue sounds alot like how my vectra used to be before i replaced the maf

[Chris Coates]

It does sound like the MAF is goosed...

[georged30]

This first one I have been getting since the car was converted to LPG and had been explained away by the installer of the LPG due to the difference in fuel mix required between petrol/LPG and air. Happy enough to accept it at the time. But this error also covers a faulty MAF sensor.

If the car runs lean or rich you are gona have engine trouble very soon valve vsr failed sensors especialy lambda . fix the staling problem and go asap to your instaler to make all the nesesery adjastments in order the car to run without check engine light.

[Stephen McVarnock]

Decided to run the car on just petrol for the past day. Still got the warning lights

http://engine-codes....volkswagen.html

http://engine-codes.com/p0335.html

But the running rich/lean warning was conspicuous by it's absence.

So for now the crankshaft sensor is now the main focus of investigation. Car will be left into the garage today. DIY just was not cutting it.

Notes on driving on petrol - car displayed stall behaviour as before just after turning on engine, notable loss of power, the occasional juddering feeling and a sense of 'stop-go-stop-go' when driving in lower gears.

The economy of the car also seems to have taken a mighty hit.

[Steven89]

In my opinon I'd say definetly the maf ... Fingers crossed the garage sorts your car out buddy

[Stephen McVarnock]

Garage fitted a new crank sensor yesterday. Car has since done 210 miles with no sign of any issues. No warnings from the ECU. no loss of power, no stalling.

Definitely looks like it was the source of the issue. There is a feeling that the crank sensor issue could also have led to the running rich/running lean warning.....

Thanks to all for the help on this matter.

cheers!

[Steven89]

glad you got it sorted

[Stephen McVarnock]

Updated another thread as it might have been related.

http://www.briskoda.net/forums/topic/180828-lpg-gas-conversion/