Engine doesnt stop when ignition ‘off’

[937carrera]

That's the standard low pressure oil switch, F22 in current track 29.

On the assumption that your '86 van has a late engine with the DOPS oil pressure system there should be a "relay 43" which controls when the oil pressure warning light comes on in the dash.

Ignition on, engine off the red LED should be illuminated.

Is there a second switch on the rear ?

[itchyfeet]

Seen this before.
there are two circuits to the engine
one is ignition live the other is thermoswitched.
mix them up and you get this

The answer was staring you in the face 10 days ago.

“The truth knocks on the door and you say, "Go away, I'm looking for the truth," and so it goes away. Puzzling.”

― Robert M. Pirsig, Zen and the Art of Motorcycle Maintenance: An Inquiry Into Values

[937carrera]

To be fair, there was more than one issue to solve, and the PO seems to have been very inventive in his deployment of electrical repairs. Your photos were an undoubted help in solving this.

Do you agree with my explanation of what was actually happening ?

To the OP, I see you said there is a second oil pressure switch, so you do have a DOPS van. Is there a wire onto the switch, or is there a brown wire with a spade on, going to earth somewhere near the dizzy ?

[itchyfeet]

Do you agree with my explanation of what was actually happening ?

I'm sorry I'm not following the tread, 10 days ago I was on holiday when I made that comment and so I was not likely to get into solving the problem and it looked like you were doing just fine without me

[937carrera]

Yeah, your holiday post explained the absence from board postings, this was my conclusion

Hmm, I have been head scratching a bit, let me have a go

I think one of the connectors on the wire from terminal 30 on the intake manifold relay was connected to the connector for N1 (choke) or N3 (by pass air valve)

Consequently, once ignition was made live, the relay engaged and the battery live from the alternator became connected to N1 or N3, each of which normally receives power from terminal 15 on the coil. The current flowed to the coil, providing voltage to the other connections on terminal 15 of the coil, which in turn connects to F35 thermoswitch and thus to the coil part of the solenoid part of the relay, keeping it permanently engaged even when ignition was off.

As suspected, itchy was pointing in the right direction all along (as no doubt did his pictures) , I'm delighted you got it sorted in the end.

Looks like another bodge on the oil pressure switches is about to rear its head. Based on what we've seen so far I'll be surprised if the wire to the rear switch isn't earthed....... and we know what'll be next

[100leelee]

Will check the wiring of the switches at the weekend....
Who knows what joys await.....

[Barybus]

Hmm, I have been head scratching a bit, let me have a go

I think one of the connectors on the wire from terminal 30 on the intake manifold relay was connected to the connector for N1 (choke) or N3 (by pass air valve)

Consequently, once ignition was made live, the relay engaged and the battery live from the alternator became connected to N1 or N3, each of which normally receives power from terminal 15 on the coil. The current flowed to the coil, providing voltage to the other connections on terminal 15 of the coil, which in turn connects to F35 thermoswitch and thus to the coil part of the solenoid part of the relay, keeping it permanently engaged even when ignition was off.

As suspected, itchy was pointing in the right direction all along (as no doubt did his pictures) , I'm delighted you got it sorted in the end.

Hello ! Sorry if I’m not doing this the correct way, I’m currently battling this same situation, owned my t25 for 2 years not had this before, I believe it’s the DG engine. recently changed my intake manifold heater relay (the one in the rear) I have a electric pump fitted as well. I changed my pierberg to Weber single DGV/DEGV (if they are the same thing - DGV/DEGV?) and in all honesty I’m lost !

I’m reading and re reading this thread to try and work out where to start.

I have ordered the relay stamped with 18 on it but this clicks when ignition is switched on and clicks when ignition turns off - is this an indication that it’s fine ?

The wire coming from the manifold is connected to the same place as before the carb swap, reading the thread you talk about this ?

The ignition coil terminal 15 is a point of interest that I need to go back and have a look at.

Basically I am giving as much information as possible in the hope that someone may be able to help! And I’m not sure where to start how to word what I’m saying or even ask the correct questions.

Any help would be appreciated as a non refundable ferry ticket has been purchased in 3 days time, and a few promises made to the misses