Oil Pressure Warning light not ON

[pfield69]

At last I've got round to testing it.
I used 1k5ohm resistir to test the circuit. the result was No lit LED.
I did notice that the pcb header pin #8 was bent and was possibly going into socket #9 (empty as shown in AngeloEVs pic). I straightened it and just inserted the PCB. The result is that with 0.3b sensor closed and 0.9b sensor open the LED flashes (engine not running). When the engine is started (0.3b sensor open) the light goes out. I have left the 0.9b wire (yellow) closed as there is no sensor to fit it to.

Also is the buzzer the small device on the PCB in the speedo?

[AngeloEvs]

Buzzer is on the PCB in speedo. You are corrrect, the wire for the high oil pressure switch needs to be earthed as leaving it disconnected will cause the buzzer to sound when your revs exceed 2000rpm. If the led is flashing with ignition on and going out with engine started then it sounds like you now have it working .....

[italianjob]

morning all

1.9 DG petrol engine 85 registered C reg

I've recently developed the notorious BOD syndrome amd I want to try and sort it out. BOD only comes on after about 30 seconds from setting off and takes anything up to 30 minutes to go off - bliss. Its been like this for the last 6 weeks - I've checked the oli and water levels and all is fine.

Was recently services a month or so before the whole BOD thing kicked off. So I'm thinking its either the low/high pressure sensors or the PCB.

Now, I've read through the wiki and most of the posts relating to the BOD - as a 'quick fix' can I simply disconnect the PCB connect from the back of the speedo to shut the thing off As a fix so I can go away in the van next weekend because I'm the support crew for a Trialwalker Team down on the southdowns.

How does the resistor fix work How does the connector go back in if there's a resistor fixed to it - or does the resistor fit on the back I promise I will get it fixed properly when I've got the money and time!

thanks for now -and as always, any advice would be gratefully recieved.

Ta

[Holydiver]

The oil pressure led is controlled by the BOD PCB in the speedo but Im curious when you decribe the oil pressure switch on 'left/top of cylinder'. The 0.3 oil pressure switch on a post 86 DG is accessed by removing the push rod tube cover plate which is underneath and not on top.

AngeloEvs
Just read this thread and you seem to know a bit about the speedo / oil pressure switch, so was wondering if you can help with a problem I've got?
Got a 91 westy Atlantic 1.6td and have been driving it now for 3 years on a KPH speedo but decided to change it for a MPH one the other week, but since fitting it the oil pressure warning light comes on once the vans upto temp but only on tick over, a quick tap on the acc peddle and it goes off. anyway I did a 300 mile trip last week and everthing seem fine with engine and oil level, accept the warning light / buzzer still goes off at tick over, after reading this thread I guess it's something to do with the speedo PCB ?? any ideas?? Ive check all the connection and they seem fine.

Any help would be good because the buzzer driving me mad

[AngeloEvs]

There is always a risk in assuming that because something happens shortly after a mod that there must be some sort of link, hopefully there is in your case but bear that in mind.

Did you swap the speedo or the entire dash assembly?
The PCBs (in the speedo) that control the Buzzer and LED are different for Diesel and Petrol. When swapping dashoboards or speedo, the PCB (in the speedo housing) must be the correct one. It may be faulty, incorrect type or there may be other issues but you could refit the original speedo or swap the PCB's over and see if the fault continues.

[Holydiver]

There is always a risk in assuming that because something happens shortly after a mod that there must be some sort of link, hopefully there is in your case but bear that in mind.

Did you swap the speedo or the entire dash assembly?
The PCBs (in the speedo) that control the Buzzer and LED are different for Diesel and Petrol. When swapping dashoboards or speedo, the PCB (in the speedo housing) must be the correct one. It may be faulty, incorrect type or there may be other issues but you could refit the original speedo or swap the PCB's over and see if the fault continues.

Sorry to ask again, so if I under stand correctly the PCB in behind the speedo face is different for Diesel & Petrol? so if I swap these over it should resovle the fault? if fitting the old one back works??.
I suppose the other option is to do away with the switch and if a oil temp and pressure gauges
Thanks for the info i'll have a play with it at the weekend I've even got an oil switch that works at a lower pressure 0.15-0.35 bar (anything better than the buzzer)

cheers again

[Aidan]

yes the bod circuit in the speedo housing is specific to fuel type (there are also various different diesel ones depending on weather p/s, air con, built on friday etc.....

the petrol one can be identified by the IC on the board it being an ITT standard chip, the diesels have unique chips with no manufacturer mark (thanks to Angelo for sharing that information - I have one spare diesel and two spare petrol bod circuits in stock)

[Holydiver]

Thanks for the info, just a bit pissed off because I bought my MPH speedo from a trader over ebay and I asked the question first "is a Diesel speedo different to a Petrol one" The answer was "NO"
Shouldn't complain that least the speedo works well.

[Aidan]

speedo isn't different only the bod circuit which isn't part of the speedo it's part of the electrical system, if you bought a speedo of me it wouldn't have the bod circuit in it, so you'd have to transfer your old one over, to be fair at that level not a lot of traders would know it's different you have to be really nerdy like me to know that there are such subtle difference

[AngeloEvs]

Hope I didn't confuse you Aiden, its the Diesel PCB that has the commercially Available Chip as described in your post and the Petrol PCB that has the VAG coded chip.

[Aidan]

you have confused me the one you labelled Petrol has the ITT chip on it
so how do you determine which of the three diesel ones which ? or is that just flashed into the chip ?

so I have 2 diesel bods and 1 petrol bods, and I'll be keeping the petrol one for my van.

If you need a diesel one anyone

[AngeloEvs]

The ITT chip is the VAG coded one for petrol, the Diesel has a stock standard 4000 series chip but to overcome any confusion in the event that the lettering/numbering has detioriated with age and unreadable I have photographed the Petrol type and the easiest distinction is the silver component (Crystal Oscillator) that sits directly to the right and held with a dab of glue. Only petrol DOP's PCBs have this fitted.

[Aidan]

ok so I have one spare diesel and one spare petrol and one in my box of spares for my van
thanks for clearing that up Angelo

[Holydiver]

Thanks for all the help, swapped the PCB in the speedo with my old one, all fixed no more low oil pressure warning.