Monitoring oil with a data tool

[UKGTC]

I thought it would be a good idea to try and see the live oil pressure data my oil pump is producing and make sure my solenoid is working correctly with the high and low pressures. I have Foxwell NT710 system scanner which goes really deep into errors but I cannot find in the live data any mention of oil pressure. It's a shame because it even shows live data for fuel temperature and pressure on both banks.

Does anyone know on this unit if there is a way of viewing live oil pressure and if not is there another data logger that does that I can use?

 

[markjay]

Does your AMG GT C actually have the oil pressure sender? Most cars today only have an oil pressure sensor that can sense low oil pressure, but not an actual oil pressure sender that can measure the oil pressure.

The reason for that is that modern engines do not need to know the actual engine oil pressure, because its not a parameter that the ECU factors in, the only relevant information is to know when the pressure is too low, to alert the driver and protect the engine from damage.

This is how we used to do it in the olden days, for cars not fitted from the factory with an oil pressure sender and gauge:

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I.e., replace the original sender with a splitter that allows fitting both the old sensor and a the new sender, then wire the sender to a new oil pressure gauge on the dash.

But this is just to demonstrate a point, I am not suggesting that you should do this on an AMG GT C.

If, however, you are convinced that the car does have an oil pressure sender as standard, then get a generic ELM 327 Bluetooth OBDII dongle and the Torque app. The app will allow you to create a virtual gauge for anything that can be read via a PID through the OBDII port, including engine oil pressure, if a pressure sender is present:

 

[UKGTC]

I am not sure if it does or not because there are several OBD2 devices that show oil pressure and are compatible with M178 engine cars. Problem is not of the sellers know enough to confirm that the data input will indeed provide oil pressure information.
I was told that the oil pressure warning is linked to going below the 2 bar at some point but there is nothing to warn if it is running 2 bar over 3000rpm when the solenoid should be allowing the ump to output 4 bar.

P3 state they do not provide OBD2 gauges for the AMG GT but I found a company in the US selling them. P3 UK checked this out and said that is correct and are investigating if it is compatible and if yes I can ask if they have oil pressure.. Much neater way to have a gauge that fits in the driver vent.

These engines cost a fortune to rebuild so I want to be confident that when I am going over 3000 the oil pressure is correct.

 

[markjay]

I am not sure if it does or not because there are several OBD2 devices that show oil pressure and are compatible with M178 engine cars...

The oil pressure sensor and oil pressure sender are peripheral to the engine, and so some cars with the same engine might have it, while some not.

I can't think what the engine ECU could possibly do with this input (oil pressure), and so I'd say that if there's no oil pressure display on the dash then there's probably no sender in the car.

As you pointed out, the car only needs to know if the oil pressure goes down below a certain threshold, but other than that, the actual value is irrelevant from the engine's perspective.

..These engines cost a fortune to rebuild so I want to be confident that when I am going over 3000 the oil pressure is correct.

I am not sure what you mean. When the engine gets hot, the oil pressure wil do down, that's normal, as the oil gets thinner.

As long as the oil pressure is above the minimum, you can rev the engine. In reality, if it turns out that the oil pressure is lower than you expected (but still above the minimum), then your only option really is to use thicker oil. There's no other way to fix low oil pressure without taking the engine apart. And always driving the car below 3,000 rpm isn't a very realistic solution either...

 

[UKGTC]

The oil pressure sensor and oil pressure sender are peripheral to the engine, and so some cars with the same engine might have it, while some not.

I can't think what the engine ECU could possibly do with this input (oil pressure), and so I'd say that if there's no oil pressure display on the dash then there's probably no sender in the car.

As you pointed out, the car only needs to know if the oil pressure goes down below a certain threshold, but other than that, the actual value is irrelevant from the engine's perspective.



I am not sure what you mean. When the engine gets hot, the oil pressure wil do down, that's normal, as the oil gets thinner.

As long as the oil pressure is above the minimum, you can rev the engine. In reality, if it turns out that the oil pressure is lower than you expected (but still above the minimum), then your only option really is to use thicker oil. There's no other way to fix low oil pressure without taking the engine apart. And always driving the car below 3,000 rpm isn't a very realistic solution either...

On most of the MB engines there is a solenoid connected to the oil pump. The pump is designed to be able to put out 4 bar of pressure if it has the correct viscosity oil and the right amount in the system. 4 bar is only possible at 3000 rpm or above because below this rpm the solenoid reduces it to 2 bar. This is one of the many features designed to make the car more efficient, even if at a very low level.
The issue is the engine will suffer premature wear if the solenoid fails because it stays in the 2 bar position and not the 4 bar. If it failed and stuck at the 4 bar position none of this would be an issue. I was told by a MB tech that if the oil pressure was too low it would cause a fault warning but if it was at 2 bar regardless of the rpm it would not.
i spoke to an MB engine builder 2 weeks ago and they had a GTC with a M178 engine in for a rebuild due to the solenoid failing. 2 bar is not enough oil pressure for doing red line pulls and will eventually destroy the engine.

I understand what you are saying about hot oil goes thinner but the solenoid issue is different because when running at the 2 bar level it also reduces the volume of oil getting circulated. It is worth searching the M157 solenoid issue to see how many cars have gone bang and the amount of owners who simply disconnect the solenoid and say how much better it runs.

 

[UkrainianHype]

On most of the MB engines there is a solenoid connected to the oil pump. The pump is designed to be able to put out 4 bar of pressure if it has the correct viscosity oil and the right amount in the system. 4 bar is only possible at 3000 rpm or above because below this rpm the solenoid reduces it to 2 bar. This is one of the many features designed to make the car more efficient, even if at a very low level.
The issue is the engine will suffer premature wear if the solenoid fails because it stays in the 2 bar position and not the 4 bar. If it failed and stuck at the 4 bar position none of this would be an issue. I was told by a MB tech that if the oil pressure was too low it would cause a fault warning but if it was at 2 bar regardless of the rpm it would not.
i spoke to an MB engine builder 2 weeks ago and they had a GTC with a M178 engine in for a rebuild due to the solenoid failing. 2 bar is not enough oil pressure for doing red line pulls and will eventually destroy the engine.

I understand what you are saying about hot oil goes thinner but the solenoid issue is different because when running at the 2 bar level it also reduces the volume of oil getting circulated. It is worth searching the M157 solenoid issue to see how many cars have gone bang and the amount of owners who simply disconnect the solenoid and say how much better it runs.

My friend from USA has his engine out right now from amg gt 4 door, due to the same issue, he got lucky for this to be spotted during comprehensive service so its being done under warranty and luckily so because its such a massive job it seems.
Apparently with m178 you cant just unplug the solenoid, so if it's stuck closed you are done.

I would've hoped the newer platform had this metric on the performance screen, but seems like it's not there. Much like with m157 where you have to connect external pressure gauge to the oil pump and rev the car to certain RPM to test it and there is no live data for oil pressure..
How stupid.

If I were you I'd get xentry connected and try to find the oil pressure value, if it's not there you need to be looking for the external install sensor.

 

[UKGTC]

My friend from USA has his engine out right now from amg gt 4 door, due to the same issue, he got lucky for this to be spotted during comprehensive service so its being done under warranty and luckily so because its such a massive job it seems.
Apparently with m178 you cant just unplug the solenoid, so if it's stuck closed you are done.

I would've hoped the newer platform had this metric on the performance screen, but seems like it's not there. Much like with m157 where you have to connect external pressure gauge to the oil pump and rev the car to certain RPM to test it and there is no live data for oil pressure..
How stupid.

If I were you I'd get xentry connected and try to find the oil pressure value, if it's not there you need to be looking for the external install sensor.

I looked into the solenoid and it appears to be the same one as on most other engines including the M157. I see they people removing theirs and some buy a cheap eBay one to have connected to the wring and not generate a fault. the one I saw just had it cable tied to somewhere out of the way.

 

[UkrainianHype]

I looked into the solenoid and it appears to be the same one as on most other engines including the M157. I see they people removing theirs and some buy a cheap eBay one to have connected to the wring and not generate a fault. the one I saw just had it cable tied to somewhere out of the way.

must be the same as m157 though, weird he said he can't just unplug, maybe he meant because of warranty.

that's good news then, i would personally not worry about the error message as it doesn't cause elm just when you scan it

 

[UKGTC]

must be the same as m157 though, weird he said he can't just unplug, maybe he meant because of warranty.

that's good news then, i would personally not worry about the error message as it doesn't cause elm just when you scan it

Yes that is what I was told, not error on the screen but kept on the log. I am getting my valve controller fitted today so I am going to get them to take a look at the solenoid and also what it takes to have a a splitter and a oil pressure gauge somewhere. With an electric sender I could have it somewhere out of the way if P3 don't have an option. It would be good to confirm the actual pressure under and over 3k rpm and again if the solenoid was disconnected. You would think they would have designed a solenoid that could fail in the 4 bar position and not the 2 bar.

 

[badgx]

Not sure if its relevant, I was looking into installing an oil pressure gauge via the oil cap. 63motorsport now sell a retro fit kit for m156 and m157, along with the wiring harness and external gauge. I wanted to get the kit specifically for the reasons you mention about, for my m157, ie having the facility to keep an eye on the 2 stage oil pressure. Mines unplugged so, it's receiving the full 4 bar oil pressure, the pressure should read a constant 4 bar instead of jumping between 2 bar to 4 bar.

No change in noise engine and yes you'll will lose a few mpg around town but I'm happy with that

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[markjay]

...I would've hoped the newer platform had this metric on the performance screen, but seems like it's not there. Much like with m157 where you have to connect external pressure gauge to the oil pump and rev the car to certain RPM to test it and there is no live data for oil pressure..
How stupid.

The reason is that engine ECU has no use for this metric. I.e., a switch that differentiates between high and low pressure is all that is needed, but the exact oil pressure figure is irrelevant as far as the ECU is concerned.

The only rationale for fitting an oil pressure sender, is if the car is also fitted with an oil pressure gauge on the dash.

And yes, mechanics may be interested in the oil pressure value, for example when evaluating if the oil pump is working properly, but then they simply connect an oil pressure gauge to the engine for testing.

 

[Bellow]

As far as I can see you don't need to monitor oil pressure only solenoid activity. Intercept its signal and tag in an LED for the dash to show the solenoid's activity - job done. Y/N?

 

[UkrainianHype]

The reason is that engine ECU has no use for this metric. I.e., a switch that differentiates between high and low pressure is all that is needed, but the exact oil pressure figure is irrelevant as far as the ECU is concerned.

The only rationale for fitting an oil pressure sender, is if the car is also fitted with an oil pressure gauge on the dash.

And yes, mechanics may be interested in the oil pressure value, for example when evaluating if the oil pump is working properly, but then they simply connect an oil pressure gauge to the engine for testing.

This makes total sense, Thanks.

But I would like to see this implemented just to alert the driver in case pressure goes down so that they stop driving and prevent further damage.

 

[badgx]

Its a really interesting thread.

For me my concerns were not so much the solenoid itself, i feel its uncommon for it to pack in, but Sods Law can do if the plunger does decide to become a bit worn & gritty in operation, similar as seen on the camshaft solenoids found in the m156.

My concern was more focused on the longevity of the 2 stage oil pump. Its not really design like a traditional variable oil pump. These 2 stage oil pumps are constructed differently, with internal veins. To me they are new in design and look fragile. We have little information on the forums about the durability, so the question for me, how long will it last at a constant 4 bar pressure, and will it loose some of its original out of the box pressure compared to say an old worn part. The internal veins and the magnesium shell within the 2 stage pump, doesn't appear that robust to me. Could be wrong though, I know someone who may know the answer, may chime along soon

On that point, not heard many bad news about these 2 stage oil pumps, would normally hear about them ususlly first appearing on the usual US and UAE forums or Tasos videos from the dusty suburbs of the desert 🏜

I don't believe the LED method would help if the plunger is stuck but definitely a good call.

 

[Bellow]

As far as I can see you don't need to monitor oil pressure only solenoid activity. Intercept its signal and tag in an LED for the dash to show the solenoid's activity - job done. Y/N?

I'm giving that a N. Because of this:

For me my concerns were not so much the solenoid itself, i feel its uncommon for it to pack in, but Sods Law can do if the plunger does decide to become a bit worn & gritty in operation, similar as seen on the camshaft solenoids found in the m156.

The solenoid could fail with the signal to it intact.

how long will it last at a constant 4 bar pressure, and will it loose some of its original out of the box pressure compared to say an old worn part.

4 bar is nothing to be concerned about.

I don't believe the LED method would help if the plunger is stuck but definitely a good call.

Ah, only noticed that bit at the end. Agreed, as per my comment at the beginning of this post.

 

[badgx]

Some goodies here but couldn't see anything listed for the m178. Just noticed SPR Autos are now listed as UK dealer. I have in the past got my parts direct from 63motorsport

Oil Pressure Gauge Readout for AMG; Protect your AMG — 63 Motorsports Inc.

63 Motorsports installs Oil Pressure Gauge to read Oil Pressure for your High Powered Mercedes-AMGs

www.63motorsports.com

 

[Bellow]

4 bar is nothing to be concerned about.

To put that in context - petrol injection pressure is typically 4 bar. Containable with plastic pipes and generated by a pump running in petrol - no oil there. Common rail diesel pressures circa 1350 bar.

 

[markjay]

To put that in context - petrol injection pressure is typically 4 bar. Containable with plastic pipes and generated by a pump running in petrol - no oil there. Common rail diesel pressures circa 1350 bar.

This one of the reasons that a petrol fuel pump costs pennies, while a Diesel HP pump costs around £1,000 (give or take). Personally, I'd avoid modern Diesel engines unless the car is still under warranty, and I said that long before the AdBlue debacle. Modern Diesel engines are fitted with a myriad of complex and expensive gadgetry, not my idea of how reliability is achieved.

 

[badgx]

To put that in context - petrol injection pressure is typically 4 bar. Containable with plastic pipes and generated by a pump running in petrol - no oil there. Common rail diesel pressures circa 1350 bar.

Oh yes, that's correct Not worried at the 4 bar pressure, what I was referring to was the unknown longevity of a 2 stage pump set to run at a constant 4 bar mode, the oil pump uses internal veins and the material used for the casing is of magnesium, appears fragile tbh. Hopefully the life expectation is not reduced by this simple mod, and lots of people have unplugged it including myself, with the view it will better aid lubrication and cooling thus preserving the m157 but hopefully doesn't come at the cost of reducing the life of the 2 stage oil pump. No reports of bad news across the pond, so I think all is cautionously good. I would definitely consider retrofitting the oil pressure gauge though for peace of mind, 63motorsport are pretty good, and im happy to pay a little extra for their parts

 

[Fastcar155]

I much prefer a dip stick to check the engine oil level because you can check the condition of the engine oil at the same time.

With the Mercedes M276 engine oil Shell 5 W 30 the oil was difficult to read because it's so clean but in the VW group Tsi 1.5 engine the Castrol oil 0 W 20 the oil has become noticeable dirty ( it does have a green dye in the oil ) but it does have the camshaft belt running in oil and the belt change is 15 years or 150000 miles which ever comes first !