Unexpected buzzer of doom

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lahoski
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Unexpected buzzer of doom

Post by lahoski »

Afternoon!

Started the van up after 10 weeks of not moving. As soon as I rev the oil pressure light comes on and I get the buzzer of doom.

I'm fairly comfortable to assume that there isn't really an oil pressure issue, as I have seen a glimmer from the light prior to this, plus the engine is cold.

I tried grounding the wire to the sender below the waterpump to the spade on the distributor, but the buzzer still goes off when the revs rise.

Is there an acceptable way to disable the buzzer so I can drive the damn thing?

Any suggestions on testing the wiring would also be gratefully received! :)

Rob
1.9 DG tin top conversion

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AngeloEvs
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Re: Unexpected buzzer of doom

Post by AngeloEvs »

After a 10 week layoff I would not rule out the possibility of low oil pressure. The oil pressure light staying on will trigger the buzzer. I would check the oil pressure is actually ok then move on to checking the two oil pressure switches, the low oil pressure switch may have got contaminated which is why the LED is faintly glowing.

The second oil pressure switch is operated by a higher oil pressure and connects to chassis whereas the the low oil pressure switch disconnects from chassis once the engine has started.

You can revert to the earlier oil pressure warning system which has the oil pressure led connected directly to the low pressure oil switch by removing the DOPs (buzzer of doom) circuit in the speedo and fitting a resistor into the socket that connects to the DOPs PCB. If you want details I can post a link to a thread that covers this modification.
1987 DG Karisma LPG with remodelled interior

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937carrera
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Re: Unexpected buzzer of doom

Post by 937carrera »

lahoski wrote: I tried grounding the wire to the sender below the waterpump to the spade on the distributor, but the buzzer still goes off when the revs rise.


I have been thinking about this and tend to agree that it isn't an actual oil pressure problem.

If you have put the wire that connects to the rear oil pressure switch onto an earth (I have a handy one on the dizzy BTW), then the DOPS should not sound.

As it is, then that tells me that the engine revs on the green wire is working correctly, but that there is a break in the wire to the switch (because the spade going to earth isn't actually providing an earth)
1981 RHD 2.0 Aircooled Leisuredrive project, CU engine
1990 RHD 1.9 Auto Sleeper with DF/DG engine

lahoski
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Re: Unexpected buzzer of doom

Post by lahoski »

AngeloEvs wrote:After a 10 week layoff I would not rule out the possibility of low oil pressure. The oil pressure light staying on will trigger the buzzer. I would check the oil pressure is actually ok then move on to checking the two oil pressure switches, the low oil pressure switch may have got contaminated which is why the LED is faintly glowing.
Oops, I meant 'haven't seen a glimmer' - I'm only ruling out because I've only seen the light flashing when I turn the ignition on and going out as soon as I start the engine.

The second oil pressure switch is operated by a higher oil pressure and connects to chassis whereas the the low oil pressure switch disconnects from chassis once the engine has started.

You can revert to the earlier oil pressure warning system which has the oil pressure led connected directly to the low pressure oil switch by removing the DOPs (buzzer of doom) circuit in the speedo and fitting a resistor into the socket that connects to the DOPs PCB. If you want details I can post a link to a thread that covers this modification.

That'd be great, thank you. Is it a permanent modification or something that can be changed back?
1.9 DG tin top conversion

lahoski
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Re: Unexpected buzzer of doom

Post by lahoski »

937carrera wrote:
lahoski wrote: I tried grounding the wire to the sender below the waterpump to the spade on the distributor, but the buzzer still goes off when the revs rise.


I have been thinking about this and tend to agree that it isn't an actual oil pressure problem.

If you have put the wire that connects to the rear oil pressure switch onto an earth (I have a handy one on the dizzy BTW), then the DOPS should not sound.

As it is, then that tells me that the engine revs on the green wire is working correctly, but that there is a break in the wire to the switch (because the spade going to earth isn't actually providing an earth)

I've tried earthing the wire on the dizzy which didn't work. I've also just tried it on the point under the coil - I think that's the rear lights are earthed? The hazards were working so I assume that the wire the oil pressure was actually earthed properly! Again, still got the buzzer sounding.

I measured the resistance across the brown wire from the sender the the split (where the other oil pressure sender wire comes up) and it was greater than 1 ohm, which seems high to me but my electrickery skills are quite poor. I can follow instructions but not actually interpret anything I find out :roll:

Is it possible to earth anywhere nearer the PCB for the buzzer?
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937carrera
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Re: Unexpected buzzer of doom

Post by 937carrera »

http://syncrosport.com/info/wiring/VW_T ... _SP_DG.pdf

Page 5:

Connector E15 on the fusebox, or the yellow wire in the 7 pin connector in the "junction box"
1981 RHD 2.0 Aircooled Leisuredrive project, CU engine
1990 RHD 1.9 Auto Sleeper with DF/DG engine

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AngeloEvs
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Re: Unexpected buzzer of doom

Post by AngeloEvs »

Untill you locate the fault you can find details of a simple mod (reversible) in the following thread....

viewtopic.php?f=39&t=167903
1987 DG Karisma LPG with remodelled interior

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