Scania P94 D9 engine - Ran fine for an hour after being parked up a month or so, but stuck some diesel in earlier and we’ve got white smoke when trundling along followed by loss of power and it’ll shut off. Restarts after a few minutes.
At first I thought it was the exhaust brake, but the smoke is white, not black - I’ve tried leaving it in the open position, although when the truck is idling, the exhaust brake cylinder tries to close (since disconnected). I assume this is to create some back pressure when idling.
Fuel tank looks very cloudy inside. Am I correct in thinking this might be water in the fuel system from sitting parked up for a month?
Advice appreciated before I attempt to drain and throw a new filter on in the morning. Wondering if adding fuel raised the water sitting in the bottom of the tank and it’s sucking that through?
stagedriver:
Parked up for the night with a little hiccup.
Scania P94 D9 engine - Ran fine for an hour after being parked up a month or so, but stuck some diesel in earlier and we’ve got white smoke when trundling along followed by loss of power and it’ll shut off. Restarts after a few minutes.
At first I thought it was the exhaust brake, but the smoke is white, not black - I’ve tried leaving it in the open position, although when the truck is idling, the exhaust brake cylinder tries to close (since disconnected). I assume this is to create some back pressure when idling.
Fuel tank looks very cloudy inside. Am I correct in thinking this might be water in the fuel system from sitting parked up for a month?
Advice appreciated before I attempt to drain and throw a new filter on in the morning. Wondering if adding fuel raised the water sitting in the bottom of the tank and it’s sucking that through?
Generally, white “smoke” is water vapour. (It can be vapourised unburnt fuel but that stinks of diesel)
With suspect fuel, I expect youre going the correct way. Clean out tank thoroughly, new filter (or two) And try again.
Or you could try putting your dip pipe into jerry can of good clean fuel? Should run fine. But if you have cloudy fuel anyway, that might just waste time as the tank needs a clean whatever.
Depending on various things water can condensate in a fuel tank. It happens less in properly sealed systems and if the tank is full of fuel not air, but can happen. If the vehicle was stood for a while could water have pooled on the tank and leaked in?
Please don’t think I’m being cheeky, but are you sure it was diesel that you topped it up with?
I’ve seen diesel engines that had petrol added to the tank in error, and they would run, but not well, until they heated up enough that the fuel started to vaporize before it got to the injectors.
The engine would stop until it cooled down a bit, then would restart and run till the temperature rose again.
I know it’s unlikely, but it can happen.
You say the diesel is cloudy. I find that depending on where I buy diesel, it is often almost opaque.
stagedriver:
Parked up for the night with a little hiccup.
Scania P94 D9 engine - Ran fine for an hour after being parked up a month or so, but stuck some diesel in earlier and we’ve got white smoke when trundling along followed by loss of power and it’ll shut off. Restarts after a few minutes.
At first I thought it was the exhaust brake, but the smoke is white, not black - I’ve tried leaving it in the open position, although when the truck is idling, the exhaust brake cylinder tries to close (since disconnected). I assume this is to create some back pressure when idling.
Fuel tank looks very cloudy inside. Am I correct in thinking this might be water in the fuel system from sitting parked up for a month?
Advice appreciated before I attempt to drain and throw a new filter on in the morning. Wondering if adding fuel raised the water sitting in the bottom of the tank and it’s sucking that through?
Generally, white “smoke” is water vapour. (It can be vapourised unburnt fuel but that stinks of diesel)
With suspect fuel, I expect youre going the correct way. Clean out tank thoroughly, new filter (or two) And try again.
Or you could try putting your dip pipe into jerry can of good clean fuel? Should run fine. But if you have cloudy fuel anyway, that might just waste time as the tank needs a clean whatever.
Depending on various things water can condensate in a fuel tank. It happens less in properly sealed systems and if the tank is full of fuel not air, but can happen. If the vehicle was stood for a while could water have pooled on the tank and leaked in?
God luck anyway, not an
Agree. A month isn’t that long to be parked up really. If it persists then drain tank, blow out lines and new filters. Could be crappy fuel also. Take a dip of it first before draining.
There’s a difference between soot caused by over fuelled combustion and unburnt diesel.
Unburnt diesel is what happens if you pour diesel onto a hot exhaust manifold or into a cylinder that isn’t reaching combustion temperature through insufficient temperature and that is deffo white smoke/vapour not black smoke.
Also water in a cylinder and vapourised by combustion is more likely to be caused by ingress from the cooling system.Storage without temperature cycling can cause gasket or seal failure in that regard.
A cooling system pressure test would be a good starting point.
It would be nice if those asking for help with technical issues who are refering to a vehicle which is not actually in the UK would mention the fact. The OP’s posting history reveals that this vehicle - a 1980’s Scania- is on a tiny island in the USA where the temperature rarely drops below 20deg. I haven’t the foggiest whether diesel sold in the USA contains biodiesel or not but In the UK it does hence:
The location, climate, age and reported use of the vehicle suggest that fuel contamination is a strong suspect. Either adding fuel to the tank, which has stood for a long time in probably humid conditions, has stirred up sediment and water; or contaminated fuel, which has been in the bulk tank or drums for a long time, has been added. This sounds like ideal conditions for diesel bug to grow.
The saving grace is that this is not a modern common rail fuel system with the associated costs of water and corrosion damage which can extend to far more than just the fuel system.
cav551:
It would be nice if those asking for help with technical issues who are refering to a vehicle which is not actually in the UK would mention the fact. The OP’s posting history reveals that this vehicle - a 1980’s Scania- is on a tiny island in the USA where the temperature rarely drops below 20deg. I haven’t the foggiest whether diesel sold in the USA contains biodiesel or not but In the UK it does hence:
As I recall isn’t there a glass bowl near the injector pump where you can see if there’s any water in the system? Also a drain plug in the filter housing so you could drain off a filter’s worth of fuel into a clear bottle, let it settle and see if there’s any water in.
