If you have the inclination you could simulate the pressure with a foot pump as long as gauge fairly accurate

just a silly question is the gauge fitted to the low pressure warning light switch
 
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Disco1BFG said:
IMHO, your first port of call here is a capilliary oil pressure gauge - preferably a Durite one. The number of times I have gone to weird engine oil pressure symptoms and it been some spurious electrical nonsense.... For instance, saw this exact issue on a vintage tractor with a (very nice looking ) electrical oil pressure gauge - readings all over the place - Capilliary gauge fitted, and all is well - same issue with a temp reading on an engine - all over the place - "garage" (!) had changed all sorts, at serious cost - turned out to the be the £5 gauge sender unit - which the temp fitting of a capilliary temp gauge found instantly.

If you still have high oil pressure after fitting a "proper" gauge, then my first port of call would be the pressure relief valve - this is designed to dump excess pressure at high engine RPM - so shouldn't really be operating at tick over - hence the importance, IMO, of getting a proper oil pressure reading.....

Good luck :)
Click to expand...

thanks! I will go through some tests and see what I can do - the point with the high RPM is a good one! So my hunch that it is the relief valve is probably wrong.
 
steve2286w said:
If you have the inclination you could simulate the pressure with a foot pump as long as gauge fairly accurate

just a silly question is the gauge fitted to the low pressure warning light switch
Click to expand...

Yes, that is my plan - I will check the sender with a multimeter to see if the problem is with the gauge or the wiring, then remove the sender and apply pressure (I have pressurised air, so the simulation is easy), that way I should be able to locate. At least it seems pretty clear that the oil flow is not the (primary) issue, that is comforting and at least I can drive!

I am not sure about your "silly question" - there is only one wire connected to the sender unit, and if it is disconnected the gauge shows zero. I am thus assuming the warning light is connected to the gauge.
Btw - could it be that my problem actually has to do with the voltage regulator for the dash indicators? I have not tested anything there, and since I have not been driving and the fuel indicator was pretty random before, I have no way of telling if the voltage regulation works - could a faulty regulator lead to this kind of false reading?
 
Good point I have read some gauges work off a regulated 10v supply rather than 12v
Do you have a green warning light for the oil pressure on with ignition and off when started up
 
steve2286w said:
Good point I have read some gauges work off a regulated 10v supply rather than 12v
Do you have a green warning light for the oil pressure on with ignition and off when started up
Click to expand...

Yes, I have the green light. It currently works as normally (on initially but off when engine runs and oil pressure high). I also had it light up (some time ago) when the oil level (and pressure) was dropping.
What surprises me is that when I put the key in position 2 then all gauges operate normally, so if the gauge is faulty then the indicator should go up as well - but it does not seem to do that. Only when the engine runs and the oil pressure actually increases does the dial start to move... So maybe the sender really has a mechanical issue. Anyway, rather than speculating I hope to get a chance to have a closer look soon!
 
kyamon said:
What surprises me is that when I put the key in position 2 then all gauges operate normally, so if the gauge is faulty then the indicator should go up as well - but it does not seem to do that. Only when the engine runs and the oil pressure actually increases does the dial start to move... So maybe the sender really has a mechanical issue. Anyway, rather than speculating I hope to get a chance to have a closer look soon!
Click to expand...

The oil pressure isn't the only thing rising when the engine is running - the output from the charging system should increase too ( dynamo or alternator ) - which would tend to implicate the voltage regulator .... this is why I consider such complication ( an electric oil pressure gauge ) smoke and mirrors.... a quality mechanical capilliary gauge tells the truth for many many years... hence my first port of call in this instance is to fit one - even if only temporarily.... you will then know .....
 
Disco1BFG said:
The oil pressure isn't the only thing rising when the engine is running - the output from the charging system should increase too ( dynamo or alternator ) - which would tend to implicate the voltage regulator .... this is why I consider such complication ( an electric oil pressure gauge ) smoke and mirrors.... a quality mechanical capilliary gauge tells the truth for many many years... hence my first port of call in this instance is to fit one - even if only temporarily.... you will then know .....
Click to expand...

I totally see your point. And unless I find a trivial electronics issue I will certainly compare the reading from my current unit with a mechanical gauge.
 
had a chance to do a couple of checks...
Battery Voltage engine off: 12.6 V
Engine idling (with choke): 12.3 V
Revving: 14.1 V

Resistance through the pressure sensor to ground is 60 Ohm with the engine off, drops to 45 Ohm when idling, and goes up through the roof when I rev it, but then it comes down again and fluctuates. Judging from the graphs I found for other oil pressure sensors this seems to be in the right ballpark, so the next thing will be to test the gauge.
Interestingly, at some point during these tests the gauge suddenly dropped to zero, but then rose back to 100. Another indication that the reading is not quite on the spot (mildly put), so I am getting confident that I can actually drive it again... Can't do a true pressure measurement just now, but that is the next step.
 
Tried a new gauge - it behaves exactly the same.
Played with the pressure relief valve to make sure it was not doing something funny, and with the little bolt above it. Makes no difference, the gauge goes to the maximum right away. It is very bizarre, because this would indicate a pressure far above 7 bars. But in this case there was no electronics involved other than the gauge - I ran a wire straight from the battery to the gauge and from there to ground. Voltage was around 13.5 V.
So my fear is that there indeed is some clogging somewhere. Since I had checked the oil flow at the rockers and did not see a crazy amount of spraying my guess is that the pressure there is no longer 7 bars. So there would have to be some resistance somewhere between the gauge and the rockers. Does anybody have a diagram of the oil flow? Does it split somewhere between the rockers and the crankshaft and if so, where is that?
 
The pressure drops on mine from 50 to 20 psi when warm 200tdi, it’s very low/ no pressure bad for engines and the green light comes on for that
 
Mine used to sit at 50 cold and warm, and since it now seems to start out at over 100 even after a drop it would be too high...
 
Update:
I removed the sump to check the oil pump and indeed found that there was an issue with the alignment of the shaft from the oil pump with the hole in the engine block. No idea where that comes from or if it has been there before (see photo). This had two consequences - the shaft was near impossible to remove from the block, and the hole for the oil to flow through to the oil filter adaptor was partially blocked because of misalignment. Although I can not completely explain why, my guess is that this is what lead to the high pressure (reading), wether it was real or not.
Unfortunately, when I finished everything and tried to fire up the engine, I had to crank it for a brief moment, and then the muffler exploded (second photo). The engine does not start, but (mis)fires quite a bit. Maybe I should get a bicycle... (kidding)
 

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Two steps forward and one step back
So the black mark on shaft next to hole suggests the pump shaft not inserted far enough ?
does anything engage on end of pump shaft stopping going fully home
And can the relief valve engage 90 degrees out
Impressive pic of exhaust

5E58FD75-4E88-41A2-80DD-2A2F21582C72.png
 
So the bend on the cover around the relief valve is probably from removing the shaft and it pressing against the inner walls of the block. I am not worried about that because it does not have a key function. The next hole up is the interesting one. It is actually a "double hole" with the shape of an 8, but I believe the top part is not supposed to be there. Somehow the locating screw (number 4 in 12.60.26. of the manual) must have been forced in so hard that it punched a new hole. I probably then dropped into that one, which indeed fixed the shaft about 5 mm too low such that the top hole in the shaft no longer lined up with the hole in the engine block.
Something stops the shaft at the top, I presume it is where the gear of the driving shaft for the oil pump engages with whatever rot it is driven by. The oil pump is now installed such that the exit hole for the oil lines up with the passage through the block, irrespective of any stop at the top.

Impressive, I agree. The sound was even more impressive :)

btw - what do you mean by "90 degrees out"?
 
Apologies if the questions sound a bit silly Not conversant with the 2.6
On my 200tdi a vacuum pump is driven off the oil pump and it needs to be inserted in a particular way
If it does not go fully home the engine prob needs turning to engage the cam
Have you opened up the pump to check gears , the little bit that broke off may have ended up in there
Where the cross is in the pump body relief valve wondering if the relief valve can be fixed in position 90 out in the cross or whether just pushed in in any position
 
steve2286w said:
Apologies if the questions sound a bit silly Not conversant with the 2.6
On my 200tdi a vacuum pump is driven off the oil pump and it needs to be inserted in a particular way
If it does not go fully home the engine prob needs turning to engage the cam
Have you opened up the pump to check gears , the little bit that broke off may have ended up in there
Where the cross is in the pump body relief valve wondering if the relief valve can be fixed in position 90 out in the cross or whether just pushed in in any position
Click to expand...

I am assuming the engine turning may become necessary if the driving shaft for the oil pump is completely removed, but I did not have to do that. The driving shaft goes down through the piece I showed on my photo, and all it does is move up and down by a few millimetres when the pump is out. Once the pump is installed the drive shaft slides back into place.

I did not go looking for the little pieces, I should probably have done that. The inside of the shaft looks smooth, so I don't know how that piece was removed, or if it was done before. Frankly, I can not imagine that I punched that hole with a bolt... But maybe I am wrong.

The relief valve is a steel ball that sits in the center of that cross and is pressed into the hole behind it by a spring, and there is no orientation when installed. I am assuming the cross-shaped channels are just for easier oil flow around and away from the ball.
 
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