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Discussion Starter #1
went 4wdriving last weekend got stuck then started blowing heaps smoke, got unstuck and checked everything over, prety much pumped 5 litres oil into air cleaner, gas/petrol setup, switched to petrol for offroading, anyways switched back to gas and disconnected hose and blocked pcv valve off and drove home, prob is now petrol tank is full oil and wont pump at all, the fuel in tank is as black as black, how is this even possible? the oil from sump has ended up in me fuel tank, anyway new pcv valve and is running sweet on gas, just cant drain dirty fuel from tank as no drain plug, sub style tank, guess tank will have to come out :(

such a simple valve but pays to check regulary as causes so many dramas, im just lucky it didnt completely drain me sump and stuff me motor
 

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nissan
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.. prob is now petrol tank is full oil ..
I know nothing about TB42s but is it a carby engine with mechanical fuel pump? You have perforated the diaphragm of the pump and will probably find some petrol in the sump as well. A small intake backfire (engine sneeze) ignites the fumes in the sump via the PCV valve. This usually blows oil everywhere including past the PCV valve back into the air cleaner, stuffs the pump diaphragm if it wasn't already stuffed and can blow the oil fill cap out of the rocker cover. The PCV valve will normally be stuffed by the original intake backfire but the crankcase ignition will finish it off anyway. I've not heard of oil being shot back down the fuel line as far as the tank but I guess it's achievable. You may also suffer various engine oil leaks like rocker cover gasket and front crank seal.

Of course I could be completely wrong but I'd almost put my money on a stuffed mechanical pump diaphragm.

Cheers,
 

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Discussion Starter #9
yes carby and mechanical pump, done front seal 3 weeks ago, old pcv valve was stuck open, was ok at low revs, but at high revs when i was stuck it pumped the oil up out top, soaked air filter and ran down carby, but these carbys the fuel bowl is opened at top, so oil enters straight into fuel bowl, but how it got back thru pump and into tank is beyond me
 

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Check the diaphragm of your pump. It is the only path from the oil system to the fuel system.

Cheers,
 

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Discussion Starter #11
tomorrow i will run it on gas with fuel lines disconnected, and see if any oil is coming from pump
 

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Discussion Starter #12
yes fuel pump stuffed :( has filled sump with petrol :( guess thats destroyed whole motor now? :(
 

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yes fuel pump stuffed :( has filled sump with petrol :( guess thats destroyed whole motor now? :(

Nah mate ,fix the pump, drain the engine oil etc new filters, and add cheap engine oil. Run till engine warm then drain oil, replace filter again and fill with good oil, should be fine.
 

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Discussion Starter #15
replaced pump, oil and filter, runs on lpg but blows heaps smoke now :( wont run petrol as cut off solenoid has stopped working :(
 

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yes fuel pump stuffed :(
I was pretty sure it would be.

has filled sump with petrol :(
I was pretty sure of that too.

guess thats destroyed whole motor now? :(
Maybe, maybe not. At least it is running so you don't have to get it fixed immediately. I know such situations can seem too big to deal with but let's take it one step at a time.

Firstly how many Ks on the engine and how keen are you to change it? If it is 400k km old and you have been dying for an excuse to replace it with a 4.8 then don't even bother reading further, but if the km aren't too bad and you like the idea of keeping the engine then read on.

Lets get it running on petrol to begin with. You seem to have gotten most of the gunk out of the tank so I wouldn't worry too much more about that. A 90 litre tankful of petrol will clean things out pretty soon. Disconnect the fuel line from the carby and crank the engine until clean petrol is coming out. You will need to disassemble the carby and give it a good clean. There are some very small passages in a carby that oil won't flush from too easily and the faulty pump will have sent a fair whack of oil in its direction. I'd say the only thing wrong with the fuel cutoff solenoid is that it is full of oil and needs flushing.

Once the carby, fuel lines, cutoff solenoid etc. are clear of oil you should be able to get it running on petrol OK. The next step is to try and determine how much damage, if any, has occurred. If you have a deep knocking at idle then that will be a stuffed big end bearing but if there are no nasty knocks then lets try and have a look at the bores. This requires something like a Milwaukee Camera poked in a spark plug hole. Do this to all cylinders and have a look at the piston wall directly opposite the spark plug hole. If there is obvious aluminium on the cylinder wall from the piston skirts then the engine has to come apart. Some mild scuffing is Ok and is to be expected. Deep scoring is another thing though. If the engine sounds and looks OK then I'd just continue to run it. As long as it isn't going through much more oil than a litre in 5000km I would be happy with it.

If it is stuffed then there are several choices that are available to you. You just need to decide what direction you want to head in.

Cheers,
 

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Discussion Starter #17
thanks for all your input, its running on petrol and gas now :) runs well on dirty petrol but guess will clog filter soon, still need to do another oil change, got solenoid to work but its stopped again now :( fitted new exhaust last week so can hear tappets now :( fitted second pcv valve in same hose so i hope i never have this problem again :) has 420 Ks on motor and about to do another 3000 end dec, just hope its right for trip, melb to adelaide and return so if it blows up i just hope someone here has spare engine for me lol
 

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thanks for all your input, its running on petrol and gas now :)
Woohoo!

runs well on dirty petrol but guess will clog filter soon,
Easy fixed.

got solenoid to work but its stopped again now :(
So replace it.

fitted second pcv valve in same hose so i hope i never have this problem again :)
I doubt that will make any difference. The problem wasn't caused by the PCV valve, it was caused by a small hole in the pump diaphragm leaking petrol into the sump. The vapours from this have ignited causing your other problems. The bang in the crank case shreds the pump diaphragm blowing oill into the fuel lines, buggers the PCV valve, spews oil anywhere it can and can cause a variety of other problems such as blowing the dipstick out of its tube and causing sump and rocker gaskets to leak. I have seem this happen twice and have talked with others that have had it happen as well. The resultant damage can be quite varied.

has 420 Ks on motor and about to do another 3000 end dec, just hope its right for trip, melb to adelaide and return so if it blows up i just hope someone here has spare engine for me lol
That's a pretty fair innings for a petrol engine. Us TD42 guys like to believe that only large capacity diesels last that long. ;) If it has been on gas for quite a while you will likely have some recession of the exhaust valves so at the very least they will need adjustment but the head may need some work. I'd be reluctant to do too much to an engine with over 400k km on it unless I was going to do everything. All the best for your Christmas trip. If it sounds OK now, I doubt you'll have a problem in the next 5000km.

Cheers,
 

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Discussion Starter #19
cut fuel pump open and sure enough diaphram was split :( one i fitted was second hand to get it goin, i shall buy new 1 now just to be on safe side, replaced cutoff solenoid and all is sweet :) cheers
 
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