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Sat Mar 20, 2010 4:38 pm

Hi- I'm really new at this.... I figured it would be easier to just ask then to look through all the goobledegop of that giant manual. I was changing my spark plugs the other day and noticed a disconnected wire. I'm not sure where it goes. It's the brown wire coming from the left white box.... it just goes down... to nowhere

Sat Mar 20, 2010 5:20 pm

Ground it.

Sat Mar 20, 2010 5:43 pm

That's what I thought.... What is the purpose of that white box anyways? Is that coming from the battery?

Sat Mar 20, 2010 5:57 pm

Those are idle air bypass solenoid valves, or idle speed boosters. You have two so that means your van is Digijet and has PS and AC, one valve for each.

When the AC compressor clutch gets powered, power also goes to one valve and it opens to allow a little extra air to bypass the throttle, which has the same effect as cracking the throttle slightly (no, it doesn't effect mixture, the air bypassed is metered air from after the AFM).

On the PS pump there is a pressure switch that senses the rise in fluid pressure from operating the steering, so that switches power to the PS valve to boost idle to compensate for the increased load.

In either case you shouldn't really notice any change in idle speed since they are calibrated to the extra load that would otherwise slow the idle. Make sure the hoses that feed air to the valves and back are intact and well-connected, these are a common source of intake vacuum leaks. You can test either valve by simply jumping power to either pin while grounding the other (there is no polarity on a solenoid). The valve will snap open audibly. If you do this with the engine idling, the idle will rise because the coresponding load is not being added.

Sat Mar 20, 2010 8:55 pm

Just to help you out in the future. A brown wire on an ACVW is a ground wire.

Sun Mar 21, 2010 7:55 am

ACVW? Why think so small? A brown wire on any German or Swedish car is a direct ground. A brown/white is a switched ground. And so on and on, there is a code to the whole system.

Sun Mar 21, 2010 8:46 am

tencentlife wrote: ACVW? Why think so small? A brown wire on any German or Swedish car is a direct ground. A brown/white is a switched ground. And so on and on, there is a code to the whole system.

10c,

Any chance there is a link to the wire color code?

Thanks! :D

Sun Mar 21, 2010 8:52 am

That's a great question. I have seen it all listed somewhere, but I didn't save a link, sorry. It ought to be in Bentley and any other manual for the cars in question. I know a few of the colors offhand but it's actually pretty comprehensive. I'll bet Mark (crazyvwvanman) can either recite the list or at least provide a link to it.

Sun Mar 21, 2010 12:35 pm

Here is an article I just found. I am trying to find out what the number at the top of every wiring diagram in the Bentley mean. The 30,X ect..
I think
30=direct connection to battery positive
50= key on or cranking
x=???

http://www.e38.org/understanding%20euro%20wiring%20diagrams.pdf

Good little article. Enjoy. I found some of the information I was looking for in it.

Sun Mar 21, 2010 12:43 pm

p. 4
http://www.e38.orgunderstanding%20euro%20wiring%20diagrams.pdf

I swear I have a better table I downloaded somewhere, but I can't find it...

Sun Mar 21, 2010 2:36 pm

Not quite on topic but I bought a English camper Conway Royale DL (look it up on youtube it's cool, the ones on YT aren't mine but the same) and took the European trailer plug off my Doka and went to wire it into my Jetta and I couldn't believe it the wires on a 2006 Jetta and 87 Doka and 89 Conway ALL MATCH just connect the same colour wires and everything worked.
If I was wiring a North American trailer I would have needed an adapter to match the Jetta and if I'm not wrong if I was wiring to a NA vehicle the wire colour would differ between vehicles (ford dodge gm).
If Europe can standardize wiring why can't everyone else???

Sun Mar 21, 2010 2:49 pm

BillM wrote: Here is an article I just found. I am trying to find out what the number at the top of every wiring diagram in the Bentley mean. The 30,X ect..
I think
30=direct connection to battery positive
50= key on or cranking
x=???

http://www.e38.org/understanding%20euro%20wiring%20diagrams.pdf

Good little article. Enjoy. I found some of the information I was looking for in it.

I was wondering the same thing not too long ago. This is what I figured reading the Bentley (wish I had your article at that time !):
(Not sure if this is correct wording, but I'll use "track" for vertical lines in Bentley schematics, and rails for horizontal ones, at top of pages).

- rail 30 is main battery fed on page 97.104, track 1
- rail 15 is when engine is running or cranking only. Fed from page 97.104, track 10. Small items only, since all the current goes through the ignition switch. So horn, backup light, not much more.
- rail X is when engine is running, but NOT cranking. Page 97.104, track 9, which feeds the load reduction relay (p. 97.111 track 86-89). Large loads, to free amps for the starter (rear defrost is one).
- rail 31 should be ground, but I'm still looking for the connexion in the schematics. Anyone ?

Edit: just found connection from rail 31 to ground on page 97.117, left of track 153.

Sun Mar 21, 2010 4:27 pm

jmranger wrote:
I was wondering the same thing not too long ago. This is what I figured reading the Bentley (wish I had your article at that time !):
(Not sure if this is correct wording, but I'll use "track" for vertical lines in Bentley schematics, and rails for horizontal ones, at top of pages).

- rail 30 is main battery fed on page 97.104, track 1
- rail 15 is when engine is running or cranking only. Fed from page 97.104, track 10. Small items only, since all the current goes through the ignition switch. So horn, backup light, not much more.
- rail X is when engine is running, but NOT cranking. Page 97.104, track 9, which feeds the load reduction relay (p. 97.111 track 86-89). Large loads, to free amps for the starter (rear defrost is one).
- rail 31 should be ground, but I'm still looking for the connexion in the schematics. Anyone ?

That what I thought,but I really wasn't sure about 31. Thanks. Makes installing an option like powerwindows to a van that didn't have them a bit easier to figure out now.

Sun Mar 21, 2010 8:25 pm

tencentlife wrote: ACVW? Why think so small? A brown wire on any German or Swedish car is a direct ground. A brown/white is a switched ground. And so on and on, there is a code to the whole system.

Not sure why I limited it to ACVW's since we were talking about a WBXer. :?

Mon Mar 22, 2010 5:42 am

[hijack :oops: ]
quick question: could a faulty PS pressure switch cause erratic idling (on an MV)?
[/hijack]

ta,
Matt

Mon Mar 22, 2010 7:54 am

Wildthings wrote: tencentlife wrote: ACVW? Why think so small? A brown wire on any German or Swedish car is a direct ground. A brown/white is a switched ground. And so on and on, there is a code to the whole system.

Not sure why I limited it to ACVW's since we were talking about a WBXer. :?

Yeah well I was going to write any European car but then I thought I wasn't sure about the French, Brits and Italians, since it's been decades since I had my hands inside any of them. The French especially love to be different for difference's sake, and the Brits are merely odd, plus they were under the dominion of the Prince of Darkness for so long. But the article linked above confirmed my earlier notion that the DIN standard was in use all over the continent. What the article doesn't point out (in a quick scan, anyway, I haven't read the whole thing closely yet) is that even the wire colors are standardised.

I had submitted a post yesterday to that effect but somehow it disappeared. I wasn't sure whether Lucas was with a C or a K so I Googled it, and the first hit was this page full of jokes. Smoke dies hard:

http://www.mez.co.uk/lucas.html

Mon Mar 22, 2010 8:00 am

Mzwo wrote: [hijack :oops: ]
quick question: could a faulty PS pressure switch cause erratic idling (on an MV)?
[/hijack]

ta,
Matt

Does yours have the same Digifant system and idle speed controller as MV's have in the US? Or does it run on Digijet and use idle boost valves like the OP of this thread? In either case the PS pressure switch is supposed to help boost idle speed to compensate for the increased load from working the steering at idle, but it works in different ways with the two systems. If you have the boost valves you should be able to check out the system the way i described above, it is bone simple.

Tue Mar 23, 2010 7:38 am

tencentlife wrote: Mzwo wrote: [hijack :oops: ]
quick question: could a faulty PS pressure switch cause erratic idling (on an MV)?
[/hijack]

ta,
Matt

Does yours have the same Digifant system and idle speed controller as MV's have in the US? Or does it run on Digijet and use idle boost valves like the OP of this thread? In either case the PS pressure switch is supposed to help boost idle speed to compensate for the increased load from working the steering at idle, but it works in different ways with the two systems. If you have the boost valves you should be able to check out the system the way i described above, it is bone simple.

MVs use Digifant the world over, as far as I'm aware. Differences between markets are likley to be subtle, though I'm a little out of my depth here. In any case, my MVs uses Digifant, which means that I haven't got boost valves, merely the pressure switch talking to the idle control unit behind the far side taillight.

I've been hunting the causes for occasional high idling and only temporary fuel shutoff/engine braking for a while (throttleswitch measures ok, its adjustment appears fine, no apparent vaccum leaks, throttle body ok, gasket will be renewed as soon as spare arrives) and, clutching at straws, I thought that maybe a faulty PS pressureswitch could be a culprit...

whatcha reckon?

cheers,
Matt