Gti engine oil light issues

[Time Bomb Tom]

Hi
I have T25 with an 8v golf gti engine, the oil light is flashing i have changed the pressure switch for a new part and this didn't make any difference, it was originally a diesel does any body have any ideas?
Many thanks.

[ghost123uk]

If your van is the type with the "DOPS" oil pressure monitoring system it requires 2 senders, one is "normally open" and one is "normally closed" and of course they have to be fed to the binnacle in the right place. Then there is the 2,000 RPM rev sensor (a complex circuit in the binnacle) = Type "buzzer" in our wiki for more info on it all !

If yours was a diesel it would have got it's revs info from a blue wire on the alternator, which is now probably not connected or even not there if you are using a non Diesel alternator, so that may well be the cause.

If it was me I would just wire it up as a simple oil warning light, using a normally closed sender (iirc the GTi engine does have one of each type fitted). If you need info on how to do that, just ask

[Time Bomb Tom]

i would be greatfull if you could show me how to do it, many thanks in advance
Tom

[Time Bomb Tom]

yes it is the golf alternator

[ghost123uk]

i would be greatfull if you could show me how to do it, many thanks in advance
Tom

OK, first a couple of questions =

What year is your van ?
Do you have a multimeter and a basic knowledge of how to use it ?
Are you OK with removing the binnacle (along with it's fairly delicate "ribbon" connecting cable) ? Or, would you rather leave that be and fit a separate light somewhere on the dash ?

Note = I cannot give you a detailed step by step "how to" but I can tell you what wires are required and where to put them, but you will have to work out how best to route the wires etc.

[ghost123uk]

Hey, "anyone else reading" = just wondering if (assuming DOPWS on this van) it might be better to put it back to standard, taking the revs feed from the coil ? Is the DOPS circuit on a Diesel (via alternator) the same as a Petrol one (via the coil) ? ( I only know about Petrol vans !)

[Time Bomb Tom]

Hi
my van is a 1990, yes i do know how to use a multimetre, i would rather connect to the original oil pressure light if that is possible?
cheers Tom

[ghost123uk]

Disconnect the -ve lead of the battery.

OK, well the first thing to do is test the 2 senders on the motor with your meter set to it's lowest Ohms, setting, and find out which one is the normally open one (closes as soon as oil pressure is there) (this is referred to as the "low pressure switch" the other being the High pressure switch of course that other one should be left disconnected )

Then you need identify at the binnacle end which wire is running back to the sender. (again using your meter as a continuity tester, you may / will need a long bit of wire to extend one of your meters leads back to the engine bay ) Or you could use the blue wire which would have been on the back of the alternator, it will still be hanging around somewhere, or you could use the one that goes to the "other" sender (after removing it from it's terminal of course) or you could even thread a fresh wire up front !

Then you cut the wire at the binnacle end and insulate the tail that is connected to the binnacle circuit end (just for safety).

Then the slightly tricky bit. You need to find out which "leg" of the oil warning LED (note = LED not bulb) has got some volts on it, and which "leg" is going to the earth track. (another reason why I asked if you are OK with the meter ).

Then, again with care, you need to cut the ribbon copper trace that is on the earth side of the LED and solder the wire you have got going to the sender on the motor to that "earthy" side of the actual LED.

This all sounds harder in print than it really is. I could do it in about half an hour (not meant as a boast by the way )

End result (and for clarity) you now have an LED being fed with 12 Volts (all be it via it's compulsory dropper resistor, but you don't need to concern yourself with that ) you then have a wire going back to the "normally closed" sender. When you turn the key on the circuit is complete and the LED lights up. When you start the engine the oil pressure opens the sender contacts, and the LED goes out. If at any time your pressure drops below the threshold of the sender, the LED comes on

Don't forget to re-connect the battery

Note = I may re-read this and E D I T to make clearer, so look back for any edits

[Time Bomb Tom]

Thank you im very greatfull

[ghost123uk]

Your welcome, note = I already edited it twice, once was when I remembered you won't actually get a 12 volt reading on the oil light because of voltage drop through it's current limiting resistor, but you will read a couple of volts on one leg (note = you will have to temporarily re-connect the battery of course, and turn the ign to "on" to get power to light up the LED for this test).

I should point out that others may consider it better to, sort out / re-wire / fix up... the full VW DOPWS (Dynamic Oil Pressure Warning System). If it was me though, I would do as I have outlined

[ghost123uk]

There is a thread about that at = http://forum.club8090.co.uk/viewtopic.php?f=39&t=85940" onclick="window.open(this.href);return false;