Oil Pressure Nightmare

[Guest MurphGti]

hi

 

i bought a 205 gti about a year ago the car has run fine since i got it but ive recently encountered a problem with the oil pressure when i put the foot down the oil pressure gauge goes way down to the red bar i was wondering if anyone can diagnose the problem?

[sub205 5]

mostly caused by a defective pressure sensor.

[Tom Fenton 1,542]

My guess would be the wiring to the sensor. The sensors themselves are pretty reliable I have found.

 

First thing to do is cut the terminal off the end of the wiring and crimp a new one. Then touch this to earth, the gauge should then read full scale. Clean the spade on the sender with some emery cloth. Then plug it back on and fingers crossed this is your problem solved.

 

If that doesn't sort it, the next place to look is the brown multiplug, but have a search, as how to fix that has been covered a few times now.

[madspikes 41 1 Cars]

My oil pressure sensor fail, was working one day, and not the next!

 

If its some times working, I would point at a wiring problem.

 

Does the oil pressure warning light come on, as this is a seperate sensor (switch), which is triggered by low oil pressure.

 

In my build thread, there is some info on testing an oil pressure sensor, its somewhere near the end of the thread.

 

Mad.

[Guest MurphGti]

My oil pressure sensor fail, was working one day, and not the next!

 

If its some times working, I would point at a wiring problem.

 

Does the oil pressure warning light come on, as this is a seperate sensor (switch), which is triggered by low oil pressure.

 

In my build thread, there is some info on testing an oil pressure sensor, its somewhere near the end of the thread.

 

Mad.

 

 

nah mate the light doesnt come on, just when i put the foot down the pressure drops down quite a bit then when i release the pedal the pressure comes up after a few seconds

[DrSarty 90 1 Cars]

nah mate the light doesnt come on, just when i put the foot down the pressure drops down quite a bit then when i release the pedal the pressure comes up after a few seconds

 

In which case then it's 99.65% likely it's what Tom suggested along with the most likely fix. The loose connection is either at the sensor itself or the brown plug by the gearbox which corrodes badly and causes all sorts of intermittent faults...just like this one.

 

There is a thread on here which shows really well how to remove/renew that brown plug.

 

So your pressure is not dropping - just the reading on the dash gauge.

 

I suspect it's the movement of the engine causing this, which to me points at the brown plug more than the sender connection, but it could be either and I'd start at the sender.

[GLPoomobile 958]

Whilst I'd agree that an electrical gremlin is likely, can you just clarify how the needle drops? Does drop smoothly? Does it drop to more or less the same point? Does it go from 'normal' to this possibly false reading almost instantly, or does it scale smoothly down the gauge to the lower point?

 

The reason I ask is that an electrical fault, such as a bad connection at the sensor, or at the brown plug, or a broken wire etc are more likely to cause very inconsistant results, such as flickering of the needle.

 

Not trying to worry you though, but please confirm how the guage behaves.

[pablo 0]

check the spade connector on the sensor, made from thinnest metal known to man and break off real easy. Might be just touching the wire by fluke but then moving around when you gun it.

[Masekwm 2]

Anyone experienced the opposite? When accelerating the car reads max then settles back to what it should be when idling?

[pablo 0]

thats what its meant to do. at higher revs you get more oil pressure.

 

will start off high too when the cars cold as the oil is thicker. then drop as the oil warms up

[Masekwm 2]

thats what its meant to do. at higher revs you get more oil pressure.

 

will start off high too when the cars cold as the oil is thicker. then drop as the oil warms up

 

It's meant to go to Max? All the way round the guage?

[pablo 0]

Mine goes near max iirc

Edited October 27, 2009 by pablo

[Masekwm 2]

Mine never used to do this, I'm sure it's electrical but hate wiring!

 

[omega 82]

Mine never used to do this, I'm sure it's electrical but hate wiring!

 

 

 

 

wow!!!

[KieranGTI 0]

A friend of mines sits at the second mark from the red, when at idle or revved with the stop light also on. What's the story.

[martyn180 9]

Mine use to do this, first I changed the spring to a new one(about £15 with spring/new sum gasket from pug and is about an hours job), and the pressure went up a little, but still fluctuated. I then cut the oil pressure wire back about in inch as it was corroded, and put a new spade on.

 

Its been fine ever since, always goes upto 3/4 even on a 150 mile run it never dropped.

Edited October 29, 2009 by martyn180

[KieranGTI 0]

Mine use to do this, first I changed the spring to a new one(about £15 with spring/new sum gasket from pug and is about an hours job), and the pressure went up a little, but still fluctuated. I then cut the oil pressure wire back about in inch as it was corroded, and put a new spade on.

 

Its been fine ever since, always goes upto 3/4 even on a 150 mile run it never dropped.

 

Nice when its easy thought there was going to be bother. There is a lot of smoke from the car too, i should of mentioned earlier mainly white on start up but does die down

the car isn't used much due to work being carried out.

[martyn180 9]

Nice when its easy thought there was going to be bother. There is a lot of smoke from the car too, i should of mentioned earlier mainly white on start up but does die down

the car isn't used much due to work being carried out.

 

 

Mine had a little blue/white smoke when cold from start up and also dies down . My next job is the valve seals, but that does not effect oil pressue, although it does burn oil, which leads to low oil presure if not topped up regulary

have you done a compression test to check the rings/valve seats?

[jord294 92]

low oil level can also cause needle to drop when accelerating hard

[KieranGTI 0]

Mine had a little blue/white smoke when cold from start up and also dies down . My next job is the valve seals, but that does not effect oil pressue, although it does burn oil, which leads to low oil presure if not topped up regulary

have you done a compression test to check the rings/valve seats?

 

No haven't had this done yet, its all pointing to the valve stem oil seals was thinking this was the problem from word go.