Fuel in cranckcase

[Shardana]

Hi, i'm Frank.
I have a 940 Estate, petrol and LPG, with a problem.
There is petrol in cranckcase, why?
What can be the cause ? I have a faulty MAF sensor for a week , and at power on I have stall problems up to 2000 rpm,but at LPG the maf sensor is excluded and the car is fine
Is possible that a too rich mixture causes gasoline leak into the oil ?
Thanks in advance
Frank

[Laird Scooby]

Originally Posted by Shardana

Hi, i'm Frank.
I have a 940 Estate, petrol and LPG, with a problem.
There is petrol in cranckcase, why?
What can be the cause ? I have a faulty MAF sensor for a week , and at power on I have stall problems up to 2000 rpm,but at LPG the maf sensor is excluded and the car is fine
Is possible that a too rich mixture causes gasoline leak into the oil ?
Thanks in advance
Frank

The petrol injectors should shut off on LPG so you shouldn't have fuel in the crankcase. You need to do a pressure check on the fuel rail, see how long it takes for the pressure to drop off after switching the engine off, it should hold pressure for at least 20 minutes. Less than that and it pints to one or more petrol injectors leaking, possibly when the car isn't running or it would show a rich mixture on both LPG and petrol, bringing the Engine Management Light on.

[Shardana]

Thanks for replay, Dave.
And if injectors is ok ?
Maf sensor is able to do this problem ?

[Laird Scooby]

The MAF sensor won't cause this, no. Almost certainly a leaky injector, possibly the cold start injector if you have one on yours.

[TonyS9]

Petrol in the crankcase can generally be caused by a rich mixture.

I would say a faulty MAF, O2 or mgt temperature sensor could cause this, aswell as leaky injectors or FPR.

Test each item before replacing.

[aardvarkash10]

Originally Posted by TonyS9

Petrol in the crankcase can generally be caused by a rich mixture.

I would say a faulty MAF, O2 or mgt temperature sensor could cause this, aswell as leaky injectors or FPR.

Test each item before replacing.

Never seen it in an efi engine. Seen it plenty in engines where the fuel pump was driven off a cam lobe. Not to say it can't happen, but...

All those things are going to cause a rich mixture, but not sooooo rich that is will cause the two things needed - total failure to ignite in the combustion chamber for long enough that the fuel can then get past the rings without evaporating in enough volume that you can see it in the oil.

Are we SURE its petrol in the oil?

[Shardana]

Originally Posted by aardvarkash10

Never seen it in an efi engine. Seen it plenty in engines where the fuel pump was driven off a cam lobe.

Are we SURE its petrol in the oil?

Yes, It's petrol .
I'm waiting new MAF.
Can I detach the flute with the injectors attached and turning the key to see if they leak?

[TonyS9]

I would be thinking about detaching the manifold, then running the fuel pump to create pressure. You could do this by just priming, turn the key (position 2 maybe) and not engage the starter. If you could measure fuel pressure that would be good too.

Up to 95 pump primes every time (thinner key)
after 96 pump primes only after about 10s of no ignition (fatter RFID key)

[Shardana]

Originally Posted by TonyS9

I would be thinking about detaching the manifold, then running the fuel pump to create pressure. You could do this by just priming, turn the key (position 2 maybe) and not engage the starter. If you could measure fuel pressure that would be good too.

Up to 95 pump primes every time (thinner key)
after 96 pump primes only after about 10s of no ignition (fatter RFID key)

Hello, i detached flute with injectors.
When i prime fuel circuit with the key, injectors spray fuel at high pression.
It's not okay !!!
Any suggestion?

[TonyS9]

If you arn't turning the engine the injectors should not fire.

Just to be clear I meant to only the turn the ignition on, this is when the fuel pump primes, do not use the starter motor.

If the injectors are leaking then they need to be replaced, but just to be sure its not an electrical issue, unplug the injectors and test again.