Low oil pressure & P164B ECM light over 3700rpm
11-10-2017, 06:18 PM
#1
AudiWorld Member
Thread Starter
Low oil pressure & P164B ECM light over 3700rpm
Before I give up on this car and trade it in for a bicycle, can anyone offer any other possible reasons for low oil pressure?
Here's the situation:
No check engine light but fault code P164B (oil pressure switch malfunction) and ECM light comes on at normal temp and revs go over 3700rpm
Oil Pressure readings are:
idle 12psi
2000rpm 24psi
3700rpm 34psi
Car was bought with seized intake balance shaft.
So far I have:
Replaced Balance shaft, timing chain, tensioner and guides.
Replaced oil pump, oil pump control valve, oil pump chain.
Cleaned out sump and oil pickup tube (Although both were quite clean)
Replaced both oil pressure switches.
Replaced the turbo. (P0299 code)
No bits were found in the sump.
I have the correct Mann filter and 5w-30 oil at the correct level.
Now I'm stuck. Rebuilding the whole bottom end is simply too much and it's not worth me putting in a new engine. So before I give up, has anyone seen any problems with the filter housing and oil cooler?
That seems to be the only thing left I could try but I don't have much hope that that will fix it.
I'm pretty sure the P164 code is simply the computer saying "Hey! its 3700rpm and the pressure switch hasn't triggered yet." Which of course means either a bad switch or low oil pressure. My switch is good and I know my oil pressure is too low.
Mark
Here's the situation:
No check engine light but fault code P164B (oil pressure switch malfunction) and ECM light comes on at normal temp and revs go over 3700rpm
Oil Pressure readings are:
idle 12psi
2000rpm 24psi
3700rpm 34psi
Car was bought with seized intake balance shaft.
So far I have:
Replaced Balance shaft, timing chain, tensioner and guides.
Replaced oil pump, oil pump control valve, oil pump chain.
Cleaned out sump and oil pickup tube (Although both were quite clean)
Replaced both oil pressure switches.
Replaced the turbo. (P0299 code)
No bits were found in the sump.
I have the correct Mann filter and 5w-30 oil at the correct level.
Now I'm stuck. Rebuilding the whole bottom end is simply too much and it's not worth me putting in a new engine. So before I give up, has anyone seen any problems with the filter housing and oil cooler?
That seems to be the only thing left I could try but I don't have much hope that that will fix it.
I'm pretty sure the P164 code is simply the computer saying "Hey! its 3700rpm and the pressure switch hasn't triggered yet." Which of course means either a bad switch or low oil pressure. My switch is good and I know my oil pressure is too low.
Mark
11-14-2017, 06:05 PM
#3
AudiWorld Member
Thread Starter
I have finally got the P164b code with the ECM warning to clear.
I changed out the 5w-30 oil and replaced it with 3qts 5w-40 and 2qts 15w-50 and took new pressure readings.
This increases the oil pressure slightly by 2 to 6psi at normal operating temperature.
_______5w-30_____ 8w-45
idle ____12 _______ 14
2000___ 24_______ 28
3700___ 34_______ 40
Although at idle and 3700rpm it is still slightly below spec, 40psi is enough to make the blue oil switch switch on, which in turn prevents the P164B code
Obviously it's not an ideal solution, but it beats staring at the ECM warning light for now.
I changed out the 5w-30 oil and replaced it with 3qts 5w-40 and 2qts 15w-50 and took new pressure readings.
This increases the oil pressure slightly by 2 to 6psi at normal operating temperature.
_______5w-30_____ 8w-45
idle ____12 _______ 14
2000___ 24_______ 28
3700___ 34_______ 40
Although at idle and 3700rpm it is still slightly below spec, 40psi is enough to make the blue oil switch switch on, which in turn prevents the P164B code
Obviously it's not an ideal solution, but it beats staring at the ECM warning light for now.
12-11-2017, 05:19 AM
#5
AudiWorld Member
Thread Starter
You mean, does the code clear switching the ignition off and back on? Yes it clears every time.
One more postscript on this situation:
I drove around for a while with the new oil viscosity and received no warning light. But when the engine REALLY reached its normal operating temperature, which sometimes takes 40 minutes (the temp gauge will read normal long before the oil has reached its highest temp), then I could get the P164b to trigger when revving to 3700rpm. However, even though I had already replaced the blue oil pressure switch, I tried using another brand. I went from a VEMO to a Beck/Arnley. The Beck/Arnley switch completely solved the problem. The warning didn't trigger in any circumstance.
My conclusion is that the switches are designed to switch within a certain range. There are slight triggering differences between brands, and if your oil pressure is close to the lower end of the spec you may get a warning if you happen to have one of the switch brands that trigger at the lower end of the range.
One more postscript on this situation:
I drove around for a while with the new oil viscosity and received no warning light. But when the engine REALLY reached its normal operating temperature, which sometimes takes 40 minutes (the temp gauge will read normal long before the oil has reached its highest temp), then I could get the P164b to trigger when revving to 3700rpm. However, even though I had already replaced the blue oil pressure switch, I tried using another brand. I went from a VEMO to a Beck/Arnley. The Beck/Arnley switch completely solved the problem. The warning didn't trigger in any circumstance.
My conclusion is that the switches are designed to switch within a certain range. There are slight triggering differences between brands, and if your oil pressure is close to the lower end of the spec you may get a warning if you happen to have one of the switch brands that trigger at the lower end of the range.
10-08-2018, 03:40 AM
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You mean, does the code clear switching the ignition off and back on? Yes it clears every time.
One more postscript on this situation:
I drove around for a while with the new oil viscosity and received no warning light. But when the engine REALLY reached its normal operating temperature, which sometimes takes 40 minutes (the temp gauge will read normal long before the oil has reached its highest temp), then I could get the P164b to trigger when revving to 3700rpm. However, even though I had already replaced the blue oil pressure switch, I tried using another brand. I went from a VEMO to a Beck/Arnley. The Beck/Arnley switch completely solved the problem. The warning didn't trigger in any circumstance.
My conclusion is that the switches are designed to switch within a certain range. There are slight triggering differences between brands, and if your oil pressure is close to the lower end of the spec you may get a warning if you happen to have one of the switch brands that trigger at the lower end of the range.
One more postscript on this situation:
I drove around for a while with the new oil viscosity and received no warning light. But when the engine REALLY reached its normal operating temperature, which sometimes takes 40 minutes (the temp gauge will read normal long before the oil has reached its highest temp), then I could get the P164b to trigger when revving to 3700rpm. However, even though I had already replaced the blue oil pressure switch, I tried using another brand. I went from a VEMO to a Beck/Arnley. The Beck/Arnley switch completely solved the problem. The warning didn't trigger in any circumstance.
My conclusion is that the switches are designed to switch within a certain range. There are slight triggering differences between brands, and if your oil pressure is close to the lower end of the spec you may get a warning if you happen to have one of the switch brands that trigger at the lower end of the range.
I have exactly the same problem. EPC light comes on because the engine is having low oil preasure. Also the same error code is generated. Can someone tell me what pressure bar specs should the blue pressure sensor have? In order to avoid this aproblem. Thank you very much.
I live in Romania and ebay or amazon is not delivering the Beck Arnley to Romania. Thank you
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10-08-2018, 07:54 PM
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Thank you
10-15-2018, 05:16 PM
#10
AudiWorld Member
Thread Starter
Pressure switch
Radu, the Vemo switch is labelled as 2.55bar (37psi) I tested the switch to see when it switched by applying air pressure and it closed at 37psi.
Europarts specifies a similar switch with the value range 2.15-2.95 bar. (31 - 42psi)
I don't think I tested the Beck Arnley one, but my theory is that the switching point is not exact. i.e. there is always some variation because of minor variations during manufacture.
Do a search on
Beck Arnley 201-1983
There are 7 or 8 suppliers, someone will be willing to ship to Romania.
Of course, this doesn't fix the root problem of low oil pressure on your car. As you can see from my post, I changed everything and the only option left was completely rebuilding the engine with the crankshaft bearings, which I was not willing to do. I think the engine will be OK at your lower pressure. To fix the warning you just have to find a switch that triggers at a lower value like at 2.3 bar.
Europarts specifies a similar switch with the value range 2.15-2.95 bar. (31 - 42psi)
I don't think I tested the Beck Arnley one, but my theory is that the switching point is not exact. i.e. there is always some variation because of minor variations during manufacture.
Do a search on
Beck Arnley 201-1983
There are 7 or 8 suppliers, someone will be willing to ship to Romania.
Of course, this doesn't fix the root problem of low oil pressure on your car. As you can see from my post, I changed everything and the only option left was completely rebuilding the engine with the crankshaft bearings, which I was not willing to do. I think the engine will be OK at your lower pressure. To fix the warning you just have to find a switch that triggers at a lower value like at 2.3 bar.