Can you hear fuel pump prime?

T81UNN

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Does the in tank fuel pump prime when the van unlocked or door opened? Should I be able to hear it?
 
Does the in tank fuel pump prime when the van unlocked or door opened?
On diesel engines - no, it does not. Only when engine is running (the pump starts when ignition is turned into START, thus immediately before engine is cranked).
 
I thought on the T6.1 it primes on driver door open? There is certainly several buzzes and whines kicking off in mine when the door opens.
 
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I thought on the T6.1 it primes on driver door open? There is certainly several buzzes and whines kicking off in mine when the door opens.
Yup, same here with my T6.1.
 
I'll try at some point, but it does involve having the "are you messing about with the van again" conversation with MrsR for assistance with the door.

As an aside if someone wanted to intercept some of the circuits that go through the harness couplers are those connectors easy to get hold of, tried looking but can't find a good search term.

Or is it just easier to depin and intercept that way?

Couple of experiments I'm considering but want to be able to easily return to stock so want to avoid cutting cable or scotch like taps.
 
I'll try at some point, but it does involve having the "are you messing about with the van again" conversation with MrsR for assistance with the door.

As an aside if someone wanted to intercept some of the circuits that go through the harness couplers are those connectors easy to get hold of, tried looking but can't find a good search term.

Or is it just easier to depin and intercept that way?

Couple of experiments I'm considering but want to be able to easily return to stock so want to avoid cutting cable or scotch like taps.

No need to break or depin anything.

I think the connectors are large enough that you can just push multimeter probe next to the wire. Use a bit of tape or something to keep the probe in place. If the connector is too tight to get a contact with probe, take a piece of thin scrap wire, attach the other end to the probe and push the other end to the connector with something thin, eg a needle. You can test the contact by turning the ignition on - then you definitely should see 12-15V.

I'm not quite sure if it looks exactly the same in T6.1 but most likely there's a similar connector block to T6 with many connectors as in below image, circled with green. 'Scuse the mess, this was taken while I was building / testing my leisure electrics setup.

1695456676060.png


> it does involve having the "are you messing about with the van again" conversation with MrsR for assistance with the door.

Place the multimeter so that you see it immediately when opening the door - no assistance needed. Or just sit in the van with doors locked for some time so that the van thinks it's time to sleep. And, keep messing with the van, it will become a routine and in couple of years no questions asked anymore! :thumbsup:
 
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Ah no, not for this, for other projects. Just thought I'd asked as the two electrics wizards were on the thread :whistle:

Yes the side harness block is the same in the 6.1 but the front relay/fuse frame is sort of reversed with the big fuse strip on the front of the seat and relays a bit behind

20230711_093811.JPG
 
blue/yellow pin
Isn't the connector (T6f/T6ao) actually under the van in T6.1 - different than it was with T6?? :unsure:

The functionality depends also on engine type. The old C-series engines have a simple fuel pump relay as T6 did.

D-series engines have a dedicated fuel pump control unit (J538) running the fuel system pressurisation pump - VCDS data suggests it's PWM driven.
 
Ah no, not for this, for other projects. Just thought I'd asked as the two electrics wizards were on the thread :whistle:

Yes the side harness block is the same in the 6.1 but the front relay/fuse frame is sort of reversed with the big fuse strip on the front of the seat and relays a bit behind

View attachment 214932

Hmm the wiring diagram says it should be 6-pin black connector in left seat box (TSKVL) but not seen in that image?
 
Hmm the wiring diagram says it should be 6-pin black connector in left seat box (TSKVL) but not seen in that image?
Isn't it actually TAK=Coupling point for fuel tank? I think the TSKVL refers only to 3-pin connector next to label "TSKVL" A bit confusing sometimes - agreed...
 
Isn't the connector (T6f/T6ao) actually under the van in T6.1 - different than it was with T6?? :unsure:

The functionality depends also on engine type. The old C-series engines have a simple fuel pump relay as T6 did.

D-series engines have a dedicated fuel pump control unit (J538) running the fuel system pressurisation pump - VCDS data suggests it's PWM driven.

You're probably right, too many versions :rolleyes:. I just went by T6.1 diagram that was available in downloads. But as @roadtripper points out, they don't cover DNAA engine.
 
I'm a DNAA engine - I don't see a wiring diagram for that specifically (there is a choice of two)
That's a shame because now it's got my interest I want to know for certain :cool:

Obviously it's high time to join the VCDS team - below a snippet from a DNAA :thumbsup:

Time06:14:3306:16:2206:18:2106:19:57
IDE00021Engine RPM/min
0​
892​
893​
1698​
IDE07824Tank-internal presupply pump 1 bank 1: activation%
10​
25.63​
26.47​
28.31​
IDE07825Tank-internal presupply pump 1 bank 1: nominal valuel/h
0​
61.7​
65.1​
70.6​

PWM data (IDE07824) 10% indicates OFF-state, as well as 90% indicates MAX blast-state. The ranges outside are for diagnostics purposes - to indicate short to ground and short to plus states.

Unfortunately ECU doesn't communicate without ignition on so VCDS can't tell what's going in there before ignition is turned on... Would the ECU run without ignition on???
 
Don't tempt me, as (mostly) a software engineer by day I intend to but I'm holding myself to a moratorium of wait till the factory warranty is done just in case...

Things like lights off with parking brake, tweaking up the lane assist and changing the behaviour of the towing socket are all very tempting. If I knew I could disable the auto close on the electric tailgate I'd be right there as having it accidentally close on the deployed rear kitchen is my constant worry - and why I'm thinking of intercepting the wiring with a switch unde the seats either at the fuse or the harness connector - crude but effective.
 
Would the ECU run without ignition on???

That's a very good point. I assume it would also communicate if it did run, even partially, for diagnostics purposes. But then you also mentioned there's the new control unit J538...
 
If I knew I could disable the auto close on the electric tailgate I'd be right there as having it accidentally close on the deployed rear kitchen is my constant worry - and why I'm thinking of intercepting the wiring with a switch unde the seats either at the fuse or the harness connector - crude but effective.

If the electric tailgate is anything like in Mrs's Audi, it doesn't take much to stop it mechanically - it's a safety feature, can easily be stopped by hand and the motors stop at that point (or even take it up again, don't recall that right now). The force would not really break anything that easily.

I think it could be easily clamped up with basically any kind of support, something like https://www.amazon.co.uk/MOUNTING-Telescopic-EXTENDABLE-Construction-Operation/dp/B00EPZZLSM spurs into mind, set up from above tail light to half-way across tailgate edge, in 45'ish angle. Maybe you can come up with something neater though, just an idea that maybe wires do not need to be harmed. ;)
 
It's quite the force actually on this one with the weight of the tailgate, I have to use both hands to stop it. I also have windbreakers and soon maybe tent over it that I'd rather it didn't trigger the close.

Anyway will start another thread on that.
 
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