Author Topic: Oil Pressure Problems..................HELP! (Read 5367 times)

MontanaGTD · « **on:** January 18, 2007, 12:56:29 pm »

Ok - i've been playing with the car a little while i've been off workj for the last few weeks.

I've fitted a y-piece in the top of the oil filter housing where the pressure sensor fits - so I could fit the oil temp and the oil pressure gauges out of an Audi coupe. I took the car out for a run tonight and the oil warning light came on and the buzzer sounded. But there is plenty of oil in it and the oil pressure gauge was showing between 3 - 5 bar (the pressure sensor and the gauge only go to 5bar!) I wondered what pressure the GTD runs at about 4000rpm? I wondered if i had broken the pressure sensor with too high a pressure?? (the original oil pressure sensor takes its reading from the top of the VDO one)

Anyone got a set of these gauges in their car??

I've take out the VDo gauge sensor and replaced the original one and the oil warning light doesnt come on and the buzzer doesnt sound!

jtanguay · « **Reply #1 on:** January 18, 2007, 01:17:53 pm »

well the oil buzzer takes a dynamic reading from two locations... the high pressure, and the low pressure. i used to know the high and low pressures of the gassers, but they might be different than the diesel.

i think it was something like 0.8 bar low side and 1.8 bar high side??? im probably wrong, but if any pressure was out of sync the buzzer would come on. the low pressure would buzz if the pressure dropped below acceptable level, and the high side would buzz if the pressure exceeded the set pressure.

maybe the tee you installed is in some way restricting the flow of oil??? or maybe the sensors are out of whack... or possibly you just need to clean the ground/contacts??? i remember someone saying that there would be a bad ground if i used teflon tape... gives you a few things to think about at least

Vincent Waldon · « **Reply #2 on:** January 18, 2007, 02:28:54 pm »

I run the VDO Audi gauge setup on my Jetta but tapped into the sensor on the block... mines a turbo so there's no room for the new oil pressure sensor on top of the oil filter.

Nevertheless the sensor that comes on when the engine is over 2000 RPM is the one on the oil filter and hence where you were working... broken or loose wire ?? Teflon tape preventing a good ground ?? The tee is metal, right ?? Did it get damaged when it was unscrewed and then placed back in ?? Dirt got into the hole ?? OK I'm reaching !

MontanaGTD · « **Reply #3 on:** January 18, 2007, 03:17:41 pm »

connector is metal (genuine VAG adapter!)

I have no idea!

jtanguay · « **Reply #4 on:** January 18, 2007, 05:27:08 pm »

hmmmm i would troubleshoot the issue as follows:

connect up all sensors like you had in the photo, but only connect the sensor wire for the idiot light.

if it still buzzes then something is wrong with the connections. if it doesn't buzz, then bad ground, or another sensor is screwing with the signal somehow??

wolfsburgnut · « **Reply #5 on:** January 18, 2007, 06:32:25 pm »

I had that exact same problem! Only it was with the gauges out of a cabriolet... but the same sensor. The gauge side of the sensor worked fine and gave a good reading that I verified with a mechanical gauge. However the dummy light contact was no good in it and would trip the dynamic oil pressure system buzzer. Here is a tip to know what sensor is giving you a problem in the future. If you hear the buzzer and get the light it is the 2bar sensor which is the one in the oil filter arm. If you just get the light it is the sensor in the head.

Peter

jtanguay · « **Reply #6 on:** January 18, 2007, 06:50:37 pm »

thanks Peter, i thought it was around 2bar

i thought that the low pres sensor would buzz too... oh well good to know!

Vincent Waldon · « **Reply #7 on:** January 18, 2007, 10:16:47 pm »

OK now I get it... you removed the original hi pressure sensor and replaced it with the Audi sensor.

Yup... won't work... the Audi is a different polarity (normally open vs. normally closed or visa versa.. at least mine is) and set for a different pressure as well.

On mine I decided to keep the orignial hi pressure sensor where it was and put the tee on the low pressure sensor hole in the block... now my oil pressure light doesn't warn me if my pressure is low when the engine is below 2000 but it will when I'm on the highway.

jtanguay · « **Reply #8 on:** January 19, 2007, 04:14:51 am »

your best bet is to have the original high pres sensor on one end of the tee, and the sensors for your gauges on other ports. you will probably need to buy an additional tee for that. just keep the original sensor closest to the oil port.

how do those dual pole pres senders work??? they say that one pole is for the idiot light, and the other is for a gauge... only makes sense that if it's from a 5 cyl audi, that the pressures would be different.

MontanaGTD · « **Reply #9 on:** January 22, 2007, 11:52:09 am »

This VDO sensor is a 1.5-5bar Audi 4 cylinder one!

Vincent Waldon · « **Reply #10 on:** January 22, 2007, 12:15:55 pm »

My Audi sensor has two poles:

One pole is from the analog pressure sensor... a variable resistance that drives the analog gauge. IFAIK there are two styles: 0-5 bar and 0-10 bar.

The second pole is a switch to ground... it has a trip pressure and a "polarity" (normally open or normally closed). It drives the idiot light, but at least in mine, both the trip pressure and the "polarity" are different than the High pressure switch that normally lives on top of the oil filter housing.

Vince