What engine damage can be caused by contaminated petrol?
Discussion
Rough101 said:
Water in the fuel wouldn’t select which one of 4 cylinders to impact in my opinion, you’d have issues in all four.
Sounds more like a stuck injector.
If they’re really, really going down this route, they’d need to support you in an insurance claim.
^ What he said.Sounds more like a stuck injector.
If they’re really, really going down this route, they’d need to support you in an insurance claim.
It is highly unlikely that bad fuel would physically damage a modern petrol engine, that have a lot of sensors and strategy to make sure they are emissions compliant. One of the big advantages to that is they are also very good a protecting themselves.
Lets roll with the dealers theory for a moment, that there is water in the fuel and that has somehow effected the combustion and ended up with a lean condition that has damaged cylinder 3. Why has it only damaged cylinder 3, the same fuel has been fed to all other cylinders.
I've got a pint on a bad injector leading to lean running and damage to cylinder 3.
Edited by Megaflow on Thursday 15th February 08:58
A misfuel could certainly damage an injector which in turn could cause the engine to run very lean or I suppose very rich. However, as someone said above, as soon as the emissions parameters drifted out of whack, the dashboard would light up like a Christmas tree and you'd have to drive quite a long way with it like that to do any appreciable damage to any part of the short-block.
Megaflow said:
Rough101 said:
Water in the fuel wouldn’t select which one of 4 cylinders to impact in my opinion, you’d have issues in all four.
Sounds more like a stuck injector.
If they’re really, really going down this route, they’d need to support you in an insurance claim.
^ What he said.Sounds more like a stuck injector.
If they’re really, really going down this route, they’d need to support you in an insurance claim.
It is highly unlikely that bad fuel would physically damage a modern petrol engine, that have a lot of sensors and strategy to make sure they are emissions compliant. One of the big advantages to that is they are also very good a protecting themselves.
Lets roll with the dealers theory for a moment, that there is water in the fuel and that has somehow effected the combustion and ended up with a lean condition that has damaged cylinder 3. Why has it only damaged cylinder 3, the same fuel has been fed to all other cylinders.
I've got a pint on a bad injector leading to lean running and damage to cylinder 3.
Edited by Megaflow on Thursday 15th February 08:58
Bit late now but was the car using more fuel than normal prior to it playing up?
Tango13 said:
Another vote for a dodgy injector, some modern petrol engines use a 'redundant spark' system so the spark plug fires whenever the piston is at TDC regardless of where it is in the cycle.
Why on earth would a manufacturer do that? And even if they did, there would be no oxygen at TDC on the exhaust stroke so any fuel erroneously injected couldn't actually ignite. If a huge amount of fuel was being injected, I guess the cylinder could hydrolock on fuel on the compression stroke but I wouldn't have thought the high pressure pump could actually supply enough fuel flow for that to happen. I would think damage is far more likely to be caused by the injector clogging, causing the cylinder to run lean and hence very hot. However, that should immediately be picked up by the ECU and flagged up on the dashboard via the MIL.
Edited by kambites on Thursday 15th February 09:19
kambites said:
Tango13 said:
Another vote for a dodgy injector, some modern petrol engines use a 'redundant spark' system so the spark plug fires whenever the piston is at TDC regardless of where it is in the cycle.
Why on earth would a manufacturer do that? And even if they did, there would be no oxygen at TDC on the exhaust stroke so any fuel erroneously injected couldn't actually ignite. If a huge amount of fuel was being injected, I guess the cylinder could hydrolock on fuel on the compression stroke but I wouldn't have thought the high pressure pump could actually supply enough fuel flow for that to happen. I would think damage is far more likely to be caused by the injector clogging, causing the cylinder to run lean and hence very hot. However, that should immediately be picked up by the ECU and flagged up on the dashboard via the MIL.
Edited by kambites on Thursday 15th February 09:19
ETA
I was wrong, I always thought it was for emissions but a quick Google suggests it's the manufacturers being cheapskates...
https://en.m.wikipedia.org/wiki/Wasted_spark_syste...
Edited by Tango13 on Thursday 15th February 09:37
As I understand it, diesel in a petrol isn't particularly damaging. Flush it out and be on your way. Your engine would run very poorly or not at all but that would be about it. Flush it out, petrol back in and after a few miles you'll never know the difference. Petrol in a diesel can be more damaging because diesel is lubricated where petrol isn't. That can cause wear on all sorts of things very quickly.
I can't imagine that you've got any diesel in your system at all, certainly not magic diesel that lights under spark ignition, only starts a fault once every few weeks and only picks one cylinder to damage.
I'd have a word with an independent inspector (Automotive Consulting Engineers are ones I've dealt with in the past) and have them come to assess your car, and get a fuel sample test done. It sounds like the warranty company are trying it on here. We've definitely not had issues before on here with warranty companies and someone's M5..
I can't imagine that you've got any diesel in your system at all, certainly not magic diesel that lights under spark ignition, only starts a fault once every few weeks and only picks one cylinder to damage.
I'd have a word with an independent inspector (Automotive Consulting Engineers are ones I've dealt with in the past) and have them come to assess your car, and get a fuel sample test done. It sounds like the warranty company are trying it on here. We've definitely not had issues before on here with warranty companies and someone's M5..
They say it "could be diesel" but this is purely conjecture, something plucked out of the air to suit their needs (i.e. not pay out). Without absolute confirmation that there is diesel fuel in there (should be easy to test for - diesel is longer hydrocarbon chains so gas chromatography / mass spectrometry - GCMS - would show this on chemical analysis) then you have reason to fight back.
Question the testing, question the interpretation of the results, question the accusation there could be diesel in there. How was the sample taken? Was it with clean items or with previously used items where they could have come into contact with anything else causing an indication of contamtination?
Absolutly get a fuel sample for yourself and get it tested yourself. But fight back, as a chemist myself regularly used to testing samples I'm very, very skeptical of this proposal that diesel is in there without any concrete evidence.
As for the things contaminated fuel can affect: fuel pumps, fuel lines, injectors, as a first point of call.
Question the testing, question the interpretation of the results, question the accusation there could be diesel in there. How was the sample taken? Was it with clean items or with previously used items where they could have come into contact with anything else causing an indication of contamtination?
Absolutly get a fuel sample for yourself and get it tested yourself. But fight back, as a chemist myself regularly used to testing samples I'm very, very skeptical of this proposal that diesel is in there without any concrete evidence.
As for the things contaminated fuel can affect: fuel pumps, fuel lines, injectors, as a first point of call.
kambites said:
Why on earth would a manufacturer do that? And even if they did, there would be no oxygen at TDC on the exhaust stroke so any fuel erroneously injected couldn't actually ignite. If a huge amount of fuel was being injected, I guess the cylinder could hydrolock on fuel on the compression stroke but I wouldn't have thought the high pressure pump could actually supply enough fuel flow for that to happen.
I would think damage is far more likely to be caused by the injector clogging, causing the cylinder to run lean and hence very hot. However, that should immediately be picked up by the ECU and flagged up on the dashboard via the MIL.
The wasted spark type of ignition system used to be very common on engines sharing ignition coils between multiple cylinders (typically pairs) where the coil being triggered to fire one cylinder at the right time would also cause a simultaneous spark in the other cylinder. As the other cylinder would be at the wrong time in the cycle for combustion to occur, the spark would do nothing, and would be "wasted" . It genuinely is (or was) a thing.I would think damage is far more likely to be caused by the injector clogging, causing the cylinder to run lean and hence very hot. However, that should immediately be picked up by the ECU and flagged up on the dashboard via the MIL.
Edited by kambites on Thursday 15th February 09:19
On more modern engines with more powerful control units adhering to more stringent emissions legislation, you typically have one coil per spark plug and each coil is driven directly by the control unit to allow for absolute control over ignition timing on a cylinder by cylinder, cycle by cycle basis, so it's no longer necessary.
Even fuel injectors used to fire in batches before control units became powerful enough to control them individually. The progress in the last 30 or so years in terms of engine management and fuelling (enabled by the advances and resulting cost reduction in computing power) has been staggering.
Limpet said:
The wasted spark type of ignition system used to be very common on engines sharing ignition coils between multiple cylinders (typically pairs) where the coil being triggered to fire one cylinder at the right time would also cause a simultaneous spark in the other cylinder. As the other cylinder would be at the wrong time in the cycle for combustion to occur, the spark would do nothing, and would be "wasted" . It genuinely is (or was) a thing.
Well you learn something new every day! In fact it turns out that my car has exactly such as system. 
The TSI has a coil pack per plug though.
popeyewhite said:
A Skoda with water injection? Stranger things. A little water should evaporate in the cylinder if it's present in fuel shouldn't it? Don't know the engine though... .
It sounds like the garage were trying to blame diesel not water. <1% water in the fuel should not be an issue. If the fuel station has messed up the maintenance of the fuel tanks you can get water in the fuel, happened to a colleagues car and the dealer went to town on it and changed the complete fuel system for £6k at the petrol stations expense though it didn't cause any damage to the engine.
In some other posts, injectors have been mentioned so as the damage is to a single cylinder it sounds like the injector is leaking fuel. In a petrol engine this will strip the oil from the piston to cylinder interface causing substantial damage by scraping the piston up and down the bore with no lubricant. If the leaking injector allowed petrol to pool on the piston then it could also hydro-locked when started and bent a con-rod.
The interesting point the OP said was the 'try starting it again advice' from the dealer, this would effectively power cycle the injection system and provide a temporary cure but do further damage.
OP, you need to get pictures of the damage to the cylinder wall and to the piston skirt (bit below the rings), damage here is due to the loss of the oil film between the two parts. You need to kick off a lot if the garage will not provide this to you.
If you Google Porsche 997.1 bore score and look at the pictures, this is the same type of damage i.e. vertical scoring that occurs when the oil film breaks down but Porsche have a different root cause.
In some other posts, injectors have been mentioned so as the damage is to a single cylinder it sounds like the injector is leaking fuel. In a petrol engine this will strip the oil from the piston to cylinder interface causing substantial damage by scraping the piston up and down the bore with no lubricant. If the leaking injector allowed petrol to pool on the piston then it could also hydro-locked when started and bent a con-rod.
The interesting point the OP said was the 'try starting it again advice' from the dealer, this would effectively power cycle the injection system and provide a temporary cure but do further damage.
OP, you need to get pictures of the damage to the cylinder wall and to the piston skirt (bit below the rings), damage here is due to the loss of the oil film between the two parts. You need to kick off a lot if the garage will not provide this to you.
If you Google Porsche 997.1 bore score and look at the pictures, this is the same type of damage i.e. vertical scoring that occurs when the oil film breaks down but Porsche have a different root cause.
Edited by FMOB on Thursday 15th February 18:44
Auto810graphy said:
Have you had the car from new? If you have this should remove doubt about wrong fuel being put into the car however contamination can’t be priced.
I assume they have checked the fuel filter as this would have to w most evidence of contamination.
We have had the car from new and it definitely has not/never been misfueled. Of cause we cannot know if we have purchased contaminated fuel. I an not aware if the filter was inspected but the fuel line was detached at the filter to get a sample several times.I assume they have checked the fuel filter as this would have to w most evidence of contamination.
Thanks.
FMOB said:
Suggest you find any receipts you have for the fuel purchases you made up to the date of the fault.
You also need a better understanding of the damage done to the engine and exactly what they have determined as the cause. The fuel testing seems to indicate possible water/diesel contamination, considering you can't fit a diesel pump nozzle into the tank of a petrol car it could down to the fuel station cocking it up.
We have considered this but there is no record or memory of where the last fill-ups took place. If it really is all as a result of contaminated fuel we hope the insurance company will pay-out.You also need a better understanding of the damage done to the engine and exactly what they have determined as the cause. The fuel testing seems to indicate possible water/diesel contamination, considering you can't fit a diesel pump nozzle into the tank of a petrol car it could down to the fuel station cocking it up.
Dynion Araf Uchaf said:
doesn’t e10 have about half a percent of water in it?
Petrol tanks in petrol stations are not 100% contaminants proof
Can you check this from where you got the petrol from?
Also 0.093 % is less than half a litre in a 50 litre tank.
It’s BS.
Also what is the significant damage? Let’s see some pics. If there is water in the engine I’d be expecting to see some bent rods, if it’s something else like a blown piston then that a timing issue.
So much more work has to be done before this diag can be confirmed
Stand your ground, get the fuel analysed and also from the petrol station.
Also I would not put it past the dealer that they have in fact started a load of work without warranty approval, in which case they won’t pay for it. I’d definitely be wanting to see exactly what warranty have said. Proof that they gave the dealer the go ahead before starting the work.
Finally raise a case with VW CS.
Can you check this from where you got the petrol from? No - not knownPetrol tanks in petrol stations are not 100% contaminants proof
Can you check this from where you got the petrol from?
Also 0.093 % is less than half a litre in a 50 litre tank.
It’s BS.
Also what is the significant damage? Let’s see some pics. If there is water in the engine I’d be expecting to see some bent rods, if it’s something else like a blown piston then that a timing issue.
So much more work has to be done before this diag can be confirmed
Stand your ground, get the fuel analysed and also from the petrol station.
Also I would not put it past the dealer that they have in fact started a load of work without warranty approval, in which case they won’t pay for it. I’d definitely be wanting to see exactly what warranty have said. Proof that they gave the dealer the go ahead before starting the work.
Finally raise a case with VW CS.
Edited by Dynion Araf Uchaf on Wednesday 14th February 20:29
Also 0.093 % is less than half a litre in a 50 litre tank. - the maths is: 0.093% of 50 ltr is 0.01 of a ltr (1 Litre = 1000 Millilitr) so in a full 50 ltr tank it would be 100 milli litres a tiny amount!
Yes I will get some photos.
The damage appears to be piston rings and cylinder liner of No3
So much more work has to be done before this diag can be confirmed - Stand your ground, get the fuel analysed - yes
I do have an insider track at VW UK (going out for supper with a VW UK HQ master tec tonight as it happens)
Thanks
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