to hydrolock a diesel engine with fuel, the injectors must spray during all 4 strokes, ie stuck open. the way a common rail injector works, this is highly unlikely. you would also have loads of smoke from the exhaust,white , black and blue depending on the severity of overfueling.
Have I hydrolocked my diesel from overpressurised rail?
- Thread starter boxerbeemer
- Start date
I was thinking about that also. So the increased amount of injected fuel in common rail engine would only result in increased revolutions am I right? I was also thinking about smoke, but this engine is fitted with DPF filter.
yes increased rpm definitely. If a diesel engine hydrolocks because of a faulty injector it'll happen when the engine isn't turning
Thank you a lot, I really appreciate your answers. I am the engine enthusiast myself, so I really always want the best for the engine, let it be a lawn mower, motorcycle or a car. I also like to do maintenance by my own. This time was my first time doing on a diesel engine, that's why I am having some doubts about what I have done.
But now, hypothetically speaking: if the engine continued to run with such a high fuel pressure all the time, would there be a chance of hydrolocking itself? As you said, it is a common rail engine and it has a precise fuel injection timing, so the RPMs should rise from the fuel overflow and probably all of the fuel would be burnt. But do you think the hydrolock could eventually happen after some time? I am speaking about running without engine load. Thank you for the answer and best regards.
But now, hypothetically speaking: if the engine continued to run with such a high fuel pressure all the time, would there be a chance of hydrolocking itself? As you said, it is a common rail engine and it has a precise fuel injection timing, so the RPMs should rise from the fuel overflow and probably all of the fuel would be burnt. But do you think the hydrolock could eventually happen after some time? I am speaking about running without engine load. Thank you for the answer and best regards.
only if the injectors fail to close and injection continues during exhaust, intake and compression stroke. That's probably why Isuzu or opel makes the ecu shut everything down, so this doesn't happen
I agree, because too much fuel injected a little before TDC, when the injection takes place, would only result in higher engine power (RPMs, since the engine was in neutral gear). It isn´t possible that the injector wouldn´t close due to the overpressurised fuel rail, right?
One more interesting question: I see that the high pressure pump has to be in - phase with the crankshaft and camshaft, which means it has to be set fixed with a bolt prior to timing belt installation. I was thinking why is this so, is it to time the injection in case a crankshaft sensor fails? Just my thoughts, I couldn´t remember anything else.
Kind regards.
One more interesting question: I see that the high pressure pump has to be in - phase with the crankshaft and camshaft, which means it has to be set fixed with a bolt prior to timing belt installation. I was thinking why is this so, is it to time the injection in case a crankshaft sensor fails? Just my thoughts, I couldn´t remember anything else.
Kind regards.
no, it's to keep the pressure more equal. It assures that the pump piston is creating pressure at the same time an injector opens.
Didn't know that, thank you for the answer.
So does the fuel pressure have any influence on closing the injectors in common rail engines? Is there a way they could stay open due to the pressure too high.
So does the fuel pressure have any influence on closing the injectors in common rail engines? Is there a way they could stay open due to the pressure too high.
First time working on a diesel, I really want to be sure I didn't mess something up ... Also I like to learn
I'm not so familiar with denso injectors, but I don't think so. They could possibly fail to open or close early though
The injectors on yours are electronically controlled through the ECM (actually EDC in this case). Pressure will not blow them open, the valve in the injector lifts upwards to allow fuel in not pushed down. The only way to totally flood a cylinder would be if the injector was defective and stuck open, if this happened you would know it.
Once triggered to open higher than normal pressure would allow more uncontrolled fuel through the injector, the control unit will sense this and shut it down.
This is the best of my understanding on these things, I am by no means a common rail diesel expert.
Once triggered to open higher than normal pressure would allow more uncontrolled fuel through the injector, the control unit will sense this and shut it down.
This is the best of my understanding on these things, I am by no means a common rail diesel expert.
That is exactly what I have also thought. I heard about how a diesel engine can get hydrolocked due to the overfueling, but the fact is, that a diesel engine controlls the power by the amount of fuel injected (at the right crank angle, of course). So the real problem, as it seems, would be injecting a fuel at the inappropriate time - during intake and compression stroke. But for that it should have a faulty or stuck open injector.
I was really worried because of the noise of the engine and the fact it stopped by itself. I am really thankful for all the answers.
I was really worried because of the noise of the engine and the fact it stopped by itself. I am really thankful for all the answers.
That "hauling" noise under no or light load could be worn pulley on your alternator.....that one with a one way clutch and bearing inside 
Turn your AC off (and other things like fan and lights etc) to take away the load from your micro belt...and listen again
Turn your AC off (and other things like fan and lights etc) to take away the load from your micro belt...and listen again
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You had already have your pulley on his way out....but when you were testing your engine with that uneven idle....pulleys clutch failed definitely...
Hello,
I am back with some back news. The car started producing a strange noise, it can be heard like knocking, and vibrations occur every time when the engine is at 1800 RPM. The vibrations occur always, no matter what the load on the engine is, whether it is in neutral or in gear, the clutch pressed or depressed ...
I took an oil sample from the dipstick tube, the oil only has 2000 km but I sent it for the analysis this week. But it seems the analysis won´t be done this year yet, because the shipping times are very long these days during corona lockdown.
Anyway, because I pumped out a little too much oil I put the rest of it in a crystal clear glass jar. I washed it several days before and dried it, it was really spotless. now, as the oil was sitting a few days inside, I see the deposits on the bottom. I have no idea what that could be. Could this be metal contamination? I have no idea any more. The tubing that was used to collect the oil was also crystal clear and clean, the pump was a vacuum pump with no direct contact with oil. And since I have a lot of waiting coming for the oil analysis to be done, these time are really not fun at all anymore ...
Deposits can be seen below on the attached picture. If anyone has had onfortunate circumstances to deal with metal conamination in oil, then please tell me whether this seems like metal contamination or not ... And the oil only has 2000 km on the clock. You would expect it to be spotless.
I am back with some back news. The car started producing a strange noise, it can be heard like knocking, and vibrations occur every time when the engine is at 1800 RPM. The vibrations occur always, no matter what the load on the engine is, whether it is in neutral or in gear, the clutch pressed or depressed ...
I took an oil sample from the dipstick tube, the oil only has 2000 km but I sent it for the analysis this week. But it seems the analysis won´t be done this year yet, because the shipping times are very long these days during corona lockdown.
Anyway, because I pumped out a little too much oil I put the rest of it in a crystal clear glass jar. I washed it several days before and dried it, it was really spotless. now, as the oil was sitting a few days inside, I see the deposits on the bottom. I have no idea what that could be. Could this be metal contamination? I have no idea any more. The tubing that was used to collect the oil was also crystal clear and clean, the pump was a vacuum pump with no direct contact with oil. And since I have a lot of waiting coming for the oil analysis to be done, these time are really not fun at all anymore ...
Deposits can be seen below on the attached picture. If anyone has had onfortunate circumstances to deal with metal conamination in oil, then please tell me whether this seems like metal contamination or not ... And the oil only has 2000 km on the clock. You would expect it to be spotless.
Attachments
put the oil through a filter paper, like a coffee filter. Then you can look at the debris after the oil has drained through. I looked at the photo butt can't tell what it is.
You can also try a magnet outside the jar to see if it's iron.
You can also try a magnet outside the jar to see if it's iron.
