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1.9 dg oil warning buzzer (with a difference)

Posted: 23 Apr 2009, 20:03
by jake1953
Having bought my van 4 weeks ago, it has sat on the drive since. All was well during the test drive and the owner brought it to my house from 50 miles away as I had no insurance. I gave it a full engine service at the weekend and prior to draining the oil, I took it for a short drive to warm the oil up. The oil light came on and the buzzer sounded. I have since changed the oil, filter, dizzy cap,rotor arm,ht leads and spark plugs also the silencer. Took it for a test drive last night(had to sort the sump plug out) and the buzzer and light still come on. in the driveway, the light goes out as soon as the engine starts. If I drive it very carefully throught the gears the light and buzzer don't come on. If I drive it "normally" they come back on. they don't like too many revs. I am going to fit a new oil pressure switch on sat am.
Does this switch only control the buzzer or does it bring on the oil light as well? when they do come on, they both come on at the same time but the light flashes- not staying on constantly.
Any tips on this one?

Re: 1.9 dg oil warning buzzer (with a difference)

Posted: 23 Apr 2009, 21:04
by jaylo264
Someone on here should be able to sort you out properly ,could be dodgy ; i know fairly little about the oil "buzzer of Doom" ( search on here for it !) except that mine used to give me grief , occ, then i gave the dashboard a slap and it stopped it . :shock:
jaylo

Re: 1.9 dg oil warning buzzer (with a difference)

Posted: 23 Apr 2009, 21:17
by ermie571
hehehe had this with mine,....driveeverywhere at less than 2500 revs and you are fine...trouble is, this restircted me to around 30-40 mph depending on gear!!

New oil pressure switch methinks! There are two- I had to replace the one near the water pump! That is a fun job!

Goodluck

Re: 1.9 dg oil warning buzzer (with a difference)

Posted: 23 Apr 2009, 23:08
by AngeloEvs
In the speedo housing lives an overly complicated circuit. This checks the condition of two oil pressure switches and the engines RPM via the ignition coil (or the Alternator on Diesel models). It controls the Buzzer and the Oil Warning LED. One oil pressure switch is set at 0.3 Bar and the other at 0.9 Bar. The circuit checks that the 0.3 Bar switch is open when the engine is started and the LED extinguishes. It also monitors the RPM and the 0.9 Bar switch, this should be closed (connected to chassis/ground) at RPM above 2000. On an healthy engine this switch will close when the engine is started from cold. If the switch opens and the RPM exceeds 2000 then the buzzer will sound and the LED will flash. This is the DOPS (Dynamic Oil Pressure Warning System) or better known as the 'buzzer of doom'. I have put a mod in the Modifications Forum which could be used to monitor what the switches are doing under driving conditions. You need to check that 0.9 Bar switch isn't opening and that the wiring/conx are OK.

Re: 1.9 dg oil warning buzzer (with a difference)

Posted: 24 Apr 2009, 08:32
by Ian Hulley
You'll know if you really have got low oil pressure 'cos the tappets drain and then the engine rattles and stops, closely followed by a sobbing noise coming from the area of your bank ballance .... trust me ... I've been there. :roll:

IIRC the B.O.D. only kicks in above a certain rpm where-as the light stays on all the time if there's low pressure.

Ian.