Low oil pressure post-mortem...
08-09-2004, 05:46 AM
#1
Junior Member
Thread Starter
Join Date: Jan 2004
Posts: 1,841
Likes: 0
Received 0 Likes
on
0 Posts
Low oil pressure post-mortem...
Once again, thanks to you all for your thoughts and input.
They gave me a pretty detailed description of what they did, when they did it, and why they did it. It all sounds plausible, but I have no way of knowing if it is the truth.
Essentially, it sounds like oil was actually leaking through the pressure sensor and it got in the pin connector and fouled it up. I meant to bring in the write-up and post it verbatim (which I will do this afternoon). 6ULDV8 I am really interested in hearing what you have to say so if you want to hold off commenting until then.
One more interesting thing to note, whatever they did, they had to take out the instrument cluster. I don't know why. In fact, I would swear that the plastic cover is brand new. My last one had a few small scratches on it and this one is so clean it has a glare. I am not sure I will ever know the whole truth.
Anyway, the good news is I have driven it over 120 miles since I have gotten it back. One trip was about 50 miles straight and have not had any problems.
John in Cincy
They gave me a pretty detailed description of what they did, when they did it, and why they did it. It all sounds plausible, but I have no way of knowing if it is the truth.
Essentially, it sounds like oil was actually leaking through the pressure sensor and it got in the pin connector and fouled it up. I meant to bring in the write-up and post it verbatim (which I will do this afternoon). 6ULDV8 I am really interested in hearing what you have to say so if you want to hold off commenting until then.
One more interesting thing to note, whatever they did, they had to take out the instrument cluster. I don't know why. In fact, I would swear that the plastic cover is brand new. My last one had a few small scratches on it and this one is so clean it has a glare. I am not sure I will ever know the whole truth.
Anyway, the good news is I have driven it over 120 miles since I have gotten it back. One trip was about 50 miles straight and have not had any problems.
John in Cincy
08-09-2004, 10:25 AM
#3
Junior Member
Thread Starter
Join Date: Jan 2004
Posts: 1,841
Likes: 0
Received 0 Likes
on
0 Posts
Detailed listing from write-up...
"Checked oil pressure, found pressure low at fast idle and up. Placed lock carrier into service position. Removed oil pan assy and removed and replaced oil pump assy. Reinstalled oil pan and degreased area of repair. Test drove car inspedcted area of repair and found oil pressure switch leaking.
Replace oil pressure switch found after test drive for oil pressure repair. Oil pressure switch leaking oil. Removed and replaced oil pressure switch, cleaned area of leakage. Test drove car noted oil light coming on checked wiring from F1 oil pressure switch to T10P/3 connector appears fine. Removed instrument cluster and checked wiring from T10P/3 to T32/10 wiring appears fine. Checked complete wiring from F1 to T32/10 all appears fine, oil light still on. Removed oil pressure switch and test operation appears fine. Test oil pressure with mech gauge and found oil pressure in spec. Applied gound at F1 connector and retest for light appears fine. Removed connector housing from wiring at F1 found oil inside connector and on pin connector. Cleaned oil from housing and pin. Reinstalled pin into housing and applied stab 22 to connector. Test drove car appears fine now. Problem caused by oil pressure switch failure forcing oil into connector and pin."
Items replaced:
oil pump 078-115-105-D
seal (4) N-906-132-01
sprocket 078-115-121-C
screw N-903-659-07
gasket 078-103-610-E
switch 06A-919-081-D
This is the order it appeared on the bill. Some of it seems "stream of consciousness" to me and a lot of it doesn't make logical sense. As always, any comments are appreciated.
John in Cincy
Replace oil pressure switch found after test drive for oil pressure repair. Oil pressure switch leaking oil. Removed and replaced oil pressure switch, cleaned area of leakage. Test drove car noted oil light coming on checked wiring from F1 oil pressure switch to T10P/3 connector appears fine. Removed instrument cluster and checked wiring from T10P/3 to T32/10 wiring appears fine. Checked complete wiring from F1 to T32/10 all appears fine, oil light still on. Removed oil pressure switch and test operation appears fine. Test oil pressure with mech gauge and found oil pressure in spec. Applied gound at F1 connector and retest for light appears fine. Removed connector housing from wiring at F1 found oil inside connector and on pin connector. Cleaned oil from housing and pin. Reinstalled pin into housing and applied stab 22 to connector. Test drove car appears fine now. Problem caused by oil pressure switch failure forcing oil into connector and pin."
Items replaced:
oil pump 078-115-105-D
seal (4) N-906-132-01
sprocket 078-115-121-C
screw N-903-659-07
gasket 078-103-610-E
switch 06A-919-081-D
This is the order it appeared on the bill. Some of it seems "stream of consciousness" to me and a lot of it doesn't make logical sense. As always, any comments are appreciated.
John in Cincy
08-09-2004, 11:31 AM
#4
Junior Member
Join Date: Jun 2004
Posts: 1,688
Likes: 0
Received 0 Likes
on
0 Posts
all very logiical and by the book, but he should have checked the gauge 1st
looks like you got an unesseesary oil pump.
the tech should have check the pressure with the mechinicla guage 1st
the tech should have check the pressure with the mechinicla guage 1st
08-09-2004, 11:45 AM
#5
Junior Member
Thread Starter
Join Date: Jan 2004
Posts: 1,841
Likes: 0
Received 0 Likes
on
0 Posts
What was illogical to me was the sequence...
although reading it another way (the first few sentences being the broad description, the rest being a detailed description of the same thing, it makes a little more sense).
So what they are saying is that they used VAG to confirm that the signal the pressure "switch" was sending to the driver information display was actually a low oil pressure signal and then just assumed that it was because of a faulty oil pump??
Furthermore, are they saying that the "switch" breaking caused the leakage and that caused an actual low pressure situation?? If anything, I would think that it would be the opposite-namely that the leakage through the switch caused it to send a signal of low pressure where none existed.
Finally, what was the relationship between the cam and valve cover work and the broken pressure switch??
I presume I will never know.
John in Cincy
So what they are saying is that they used VAG to confirm that the signal the pressure "switch" was sending to the driver information display was actually a low oil pressure signal and then just assumed that it was because of a faulty oil pump??
Furthermore, are they saying that the "switch" breaking caused the leakage and that caused an actual low pressure situation?? If anything, I would think that it would be the opposite-namely that the leakage through the switch caused it to send a signal of low pressure where none existed.
Finally, what was the relationship between the cam and valve cover work and the broken pressure switch??
I presume I will never know.
John in Cincy
Trending Topics
08-09-2004, 05:12 PM
#9
Junior Member
Join Date: May 2004
Posts: 1,495
Likes: 0
Received 0 Likes
on
0 Posts
Anatomy of a Wild Goose Chase (long)
Based on that information they gave you, I have to agree that the sequence of events here are out of whack. Its really not that important because you can easily put it together in the proper order. The tech puts his cryptic notes on the service order and then a service advisor writes it out so the customer can make sense of it. So in the translation these things never get written out perfectly, but this write up is far more detailed than most. I'm a guessing that because you asked them specifically to do so. There is enough detail here to paint a good picture.
Lets start with the first sentence. It says "Checked oil pressure, found pressure low at fast idle and up". In a previous post you said that the service manager told you that their "computer told them the oil pump was reading no pressure". I assumed that he just misspoke and meant that the oil pump was "producing" no pressure as oil pumps arent very good at reading anything. In one of my previous posts I joked that "oil pressure is checked with a mechanical gauge, not some VAG box". Let me clarify that as I should have done so earlier. It is possible to perform a simple test of the oil pressure system using a Vag 1551, VAS or probably even a VAG COM for that matter. The specification for oil pressure on your car is a minimum of 2 bar with coolant temp minimum 80 degrees Celsius and engine RPM at 2000. Using a 1551, display field 3 of group 1 of the instrument cluster will give you a pass-fail type reading. Its either oil p2<min (less than minimum) or oil p2 OK. I feel pretty certain that this was the beginning of the techs problem. The clue that he was going by this simple VAG test were the words "low at fast idle and up" in the first sentence and the previous "computer" comment by the service manager. Because he was getting a reading of below minimum he assumed that the sender was working the way it was supposed to. This is a classic case of, you can do it that way, but you really should do it the right way. The right way being pull the sender and hook up a mechanical gauge and get pressure readings at various engine speeds. Convinced that the sender was sending and the oil pressure circuit was functioning it was on to what builds oil pressure. That the car only had 49K miles on it would be highly unlikely that engine wear would be the cause for the pressure loss so it was natural to assume the oil pump was either bad or the pick up screen was being blocked. Screens blocked in 1.8T's are a common problem for those that don't change their oil regularly. Once he pulled the pans and saw nothing that might have clogged the screen he replaces the pump. Yikes! He's really scratching his head now cause that didn't work. Back to the oil pressure circuit. Knowing that the pump is new and the sender is sending, it must be a problem in the wiring or the instrument cluster. Now here is where we will probably never know for sure what happened. You mentioned that you think you have a new cluster in your car. Do you still think so? I believe that's a very good possibility and heres why. Had he performed the wiring tests he described in the write up he would have immediately seen that the sensor was leaking and that would have been the end of it. No need to check any wiring at all. The sensor is a single wire with a spade connector covered with a protective rubber boot to keep water out. There is no housing that they mention in the write up. Very often if the sender has not been leaking very long, the boot will fill with oil and not appear to be leaking at all. Still convinced that the sender was sending I think he put a cluster in the car thinking it was in the circuit board. Then and only then did he work his way back to the sender. Once he peeled the rubber boot off to do his wiring test he saw that the sender was leaking and indeed the problem all along. It was his downfall to assume that since the sender was giving a signal it must be Ok. He never imagined that the signal could have been wrong. If that is indeed the way it went I'm not sure how they going to bill out the cluster because no way is Audi going to eat both a cluster and oil pump for the same problem. I do know one thing however, that tech has never been so happy to see the *** end of a car in his life.
Lets start with the first sentence. It says "Checked oil pressure, found pressure low at fast idle and up". In a previous post you said that the service manager told you that their "computer told them the oil pump was reading no pressure". I assumed that he just misspoke and meant that the oil pump was "producing" no pressure as oil pumps arent very good at reading anything. In one of my previous posts I joked that "oil pressure is checked with a mechanical gauge, not some VAG box". Let me clarify that as I should have done so earlier. It is possible to perform a simple test of the oil pressure system using a Vag 1551, VAS or probably even a VAG COM for that matter. The specification for oil pressure on your car is a minimum of 2 bar with coolant temp minimum 80 degrees Celsius and engine RPM at 2000. Using a 1551, display field 3 of group 1 of the instrument cluster will give you a pass-fail type reading. Its either oil p2<min (less than minimum) or oil p2 OK. I feel pretty certain that this was the beginning of the techs problem. The clue that he was going by this simple VAG test were the words "low at fast idle and up" in the first sentence and the previous "computer" comment by the service manager. Because he was getting a reading of below minimum he assumed that the sender was working the way it was supposed to. This is a classic case of, you can do it that way, but you really should do it the right way. The right way being pull the sender and hook up a mechanical gauge and get pressure readings at various engine speeds. Convinced that the sender was sending and the oil pressure circuit was functioning it was on to what builds oil pressure. That the car only had 49K miles on it would be highly unlikely that engine wear would be the cause for the pressure loss so it was natural to assume the oil pump was either bad or the pick up screen was being blocked. Screens blocked in 1.8T's are a common problem for those that don't change their oil regularly. Once he pulled the pans and saw nothing that might have clogged the screen he replaces the pump. Yikes! He's really scratching his head now cause that didn't work. Back to the oil pressure circuit. Knowing that the pump is new and the sender is sending, it must be a problem in the wiring or the instrument cluster. Now here is where we will probably never know for sure what happened. You mentioned that you think you have a new cluster in your car. Do you still think so? I believe that's a very good possibility and heres why. Had he performed the wiring tests he described in the write up he would have immediately seen that the sensor was leaking and that would have been the end of it. No need to check any wiring at all. The sensor is a single wire with a spade connector covered with a protective rubber boot to keep water out. There is no housing that they mention in the write up. Very often if the sender has not been leaking very long, the boot will fill with oil and not appear to be leaking at all. Still convinced that the sender was sending I think he put a cluster in the car thinking it was in the circuit board. Then and only then did he work his way back to the sender. Once he peeled the rubber boot off to do his wiring test he saw that the sender was leaking and indeed the problem all along. It was his downfall to assume that since the sender was giving a signal it must be Ok. He never imagined that the signal could have been wrong. If that is indeed the way it went I'm not sure how they going to bill out the cluster because no way is Audi going to eat both a cluster and oil pump for the same problem. I do know one thing however, that tech has never been so happy to see the *** end of a car in his life.