Not your average oil pressure issue

**Mott6904** · 12-26-2008 10:10 PM

I just bought a 99 a4 and it has been nothing but problems ever since. I bought it with a broken timing belt and rebuilt the head and put all updated timing parts in. All was good besides the oil light came on, so i replaced the oil pressure sending unit. the light still came on, So i pulled the pan and it was a little sludged but the pickup was not clogged. I bought a new oil pump with pickup and replace it today, but it still comes on. I put an oil pressure gauge in place of the the temperature sender. Before when it was cold i was getting at the most 40 psi at the most then when it warmed up it wouldnt go above 20 and at idle it was around 10psi. So when i replaced the pump and first started it shot up to 80 - 90 psi. at idle its around 20 psi and cruisin around 30-40 psi. I checked the wire going from the sender to the connection in the ecu box with a continuity tester while wiggling the harness and it never lost broke its connection. What do you guys think i should test now. This thing is pissing me off and i only bought it for a good daily driver since my nissan eats way too much gas. please help Im lost and dont know where to go from here. Yes i searched and nothing matched my cituation.

**Militant-Grunt** · 12-26-2008 11:24 PM

What oil weight do you use?

**Mott6904** · 12-27-2008 01:02 PM

i was using mobile 5w30. this time i used a cheap napa 10w30 to see if my problem was fixed before i put the expensive crap in. The light comes on a t 25 psi which doesnt make any sense to me when idle spec is as low as 14 psi.

**Mawhitey** · 12-27-2008 04:19 PM

You sure the right switch fitted? as iirc there is a few different pressure ones, if its deffo iddling @ 20psi when warm then you bang on buddy. I assume no rattling from the lifters?

**kjgarreau** · 12-27-2008 05:38 PM

The switch doesn't trigger until 2000 RPM... if it can't verify minimum pressure then you get a light. You might have gotten the wrong switch, what part number did you get?

**Mott6904** · 12-28-2008 10:07 PM

068919081 thats the part number from the autohausaz.com website. It says it is a 1.4 bar switch which equals 20 psi, but it comes on a 24-27 psi? There is also a 3.6 psi and 4.4 psi switch on the website but they seem a little low. this is pissing me off because i just bought the car for 1000 dollars and then rebuilt and replaced everything that normally go wrong with these cars and this is all thats left to do. This little thing is keeping me from driving the car much becuase they light scares me.

**Mawhitey** · 12-29-2008 01:03 PM

That apears to be the right number, and spec, it seems your new one maybe faulty then
you could try 068919081A instead, thats 0.9 same thread and all

**quattro16** · 12-29-2008 01:33 PM

Sounds like a cluster problem if the actualy mechanical oil gauge is reading correctly.

**Mott6904** · 12-29-2008 09:37 PM

sometimes if dips down to 15 psi at idle but that is still within specs. im going to remove to oil filter housing and see if there is some junk in that and replace the sensore with the .9 i guess and then do an engine flush again. I dont think there is much junk in the engine because i just had the head and pan off and hot tanked. Do you guys recomend the diesel fuel flush? i think i might have a maf problem Im not getting the best of gas mileage,it is a little doggy, and shifts too soon sometimes. But i dont know I might just be use to my 450hp nissan or my 05 r1, how knows