weird wiring gremlins.

[pionte]

I am after some help and advice concerning a strange electrical problem that I cant get my head around...

Its a van belonging to a young lady who lives close to me that is having problems so asked for help on social media, she has been messed around and generally taken for a ride by a long precession of mechanics who have maybe seen her as an easy touch and have charged money and not sorted the problems, so I have decided to try and help her ( not for any financial payment, but because I dont like to see people taken advantage of )

The van is a diesel ( thought from a golf ) fitted by some previous spanner wielding monkey no doubt

The problem.

After driving it back from the local garage who conducted the MOT test , it was turned of then the next time it was going to be used it would not start, or even turn over. A mechanic was called out, charged her £100 and told her it was the battery... It wasnt.

The next mechanic came and told her it was the starter motor, fitted a new one , charged her and left... it still did the same , no cranking atall.

So today I went to have a look and see if I could help, in my mind I thought it could be the ignition switch... im 99% sure that it isnt.

This is what I found.

When the ignition is turned on, this solenoid continuously buzzes and clicks..




There was 3 wires left dangling inside the engine bay.. 2 come from the same part of wiring loom as the brown wire for the glow plugs.


a white and blue one ,, live .( this was bare so I made safe with a red spade terminal )

A black one, this seemed to be an earth, again bare so I made safe. When I connected this the negative side of the battery the solenoid stopped buzzing...

A third wire red and yellow , coming from the same part of a loom for the temperature sender

didnt appear to be either a live or negative !


The starter motor was brand new, but some things here didnt make sense either. The main live cable directly to the battery positive was permantly live as it should be, the spade terminal that goes to ignition switch was also live whilst connected .... disconnected the wire to it was not live , untill you cranked then it became live ( as i thought it should ? ) but why is the spade terminal live ?

The brown wire going to the glow plugs was also strange, this was negative, surely this should have been positive??

My first thought was a bad earth,I checked the nose of the gearbox and battery earth, all good . so I connected a good quality jump lead from the bell housing/starter motor straight to the negative side of the battery just to discount this. No difference found.

So I am after any help that can be offered, can you confirm what the 3 mystery wires are , where they should go and what polarity they should be...

Am I correct in my thinking that the starter motor should have a permanent live ( thick cable ) and the spade should be only live whilst cranking ??

Also should the wire to the glow plugs not be a live ??

and what is this all about ? it seems neither live or negative


The electrics are a mess, ideally it needs a auto electrician who knows these vans. Although I trained as a auto electrician and qualified as a mechanic it was a long time ago, and I am no doubt rusty . I know my van but its a petrol and the electrics are as VW intended !

This young lady has been taken for a ride by guys that in the least deserve some bad karma... so I am hoping that with your help we can help her keep the van and put a smile back on her face.

Thanks for any help offered

Martin.

[ZsZ]

What is the year of the van? (from chassis nr.)
The relay is a glow plug relay, I think it is gone mad, try to source a working used one.
The thick wire looks a faded dirty red to me and then it is the glow plug switched live.

The blue/white is temp sender for the glow plug relay. The sender located in the coolant flange at the front of the head. The glow plug switch on when the engine is cold. If not connected, the glow plugs are working even on hot engine.
Not sure about the black, should be connected to an "electromagnetic switch" in contact with the X bridge on later buses.
The red/yellow should be connected to the coolant temp sender. The sender located in the coolant flange at the side of the head.

All above give signal as resistance to negative.

Starter should be connected as you described, that connecting point on rubber insulation is not from factory.

german wiring diagrams:
http://vwt3.hu/files/egyeb/Stromlaufpla ... 0-1985.pdf
http://vwt3.hu/files/egyeb/Stromlaufpla ... 6-1992.pdf

[Jakemate]

What's the voltage at the starter on the crank wire while cranking ?

[ELVIS]

Skim read pics as fighting with the youngest right now


Black is fuel stop solenoid on top of the pump, should be live when ignition is on...................

[ZsZ]

What's the voltage at the starter on the crank wire while cranking ?

the manual says more than 8V
http://vwt3.hu/files/egyeb/Elektrische_Anlage.pdf

on german forums they say it must be 12V

Black is fuel stop solenoid on top of the pump, should be live when ignition is on...................

Ohh... Fck I forgot that

[ELVIS]

Think brother ZsZ has covered most of it.

Got better quality pics of what that 'thing' is with all the wires hanging off it? give us a description of what is going where.

Presumeably you are au fait with basic wiring circuit for battery-starter-alternator-Live feed to P1 terminal in black box?

Before you worry about the whole van and its issues, break it down to getting it cranking first.

Live feed from fully charged battery to starter. is the solenoid spade deffinitely deffintely deffinitely live with nothing on it? take off the trigger wire (black/red i think?!) if you bridge the starter from the live feed to the solenoid with a heavy screwdriver it should turn over.

If you are positive about the solenoid being live its a duff starter, as you say, should be triggered when cranking when key is fully turned (position 3?) then when you let go of the key the ignition feed is cut.

IF the solenoid terminal is deffinitely live when nothing is connected to it, in therory, the starter should be continuously turning/cranking.

let us know how you get on chap

[pionte]

Guys thank you for taking the trouble to reply... very much appreciated .

I am going to head back on over tomorrow morning and take another look, and double check my findings.

I didnt test Voltages with a AVO meter as the one I carry in the van had a flat battery , I will take my other one with me tomorrow. I was just doing basic testing using a 12v test lamp, this at least told me if I had current and what polarity by swapping from + to - on the battery. I will check tomorrow and report what Voltage is present.

I was expecting the starter to spin when I supplied 12v to the solenoid, although to be fair I cant ( without a working AVO meter ) be certain that the battery is giving a healthy voltage, when position 3 is selected on the key there is no dimming of lights , which suggests that the circuit is not being completed and the starter is not even trying to be engaged .

My haynes manual is for the petrol engine only, so it doesnt give diagrams for diesel, thank you ZsZ for linking to the German one, I will have a look through and see if it can give me some pointers. My first concern is to get the thing cranking... I think that there is something fundamentally wrong at the moment, it must be a broken or incorrectly fitted wire somewhere, maybe something done by one of the previous mechanics that have looked at it. I was baffled when I couldnt get the starter to engage by bypassing the ignition wire.

Thank you again, and I will post my findings after tomorrow and take less blurry pictures !

Martin

[pionte]

A huge thank you to Elvis, Zsz and Jakemate for taking the time and effort to reply.

Armed with a fully functioning AVO meter ( amazing how much information can be gained by using the correct tools !) I was able to discover that I was NOT getting 13v to the spade on the starter motor, a quick check of the ignition switch ruled that out as the culprit, and a proper test of the battery showed that it must have a dead cell as the voltage was dropping of quickly after being on charge over night, so jumped from another car the van finally span over.

The next job was to connect the wires as you described and I found the break in the wire going to the fuel stop solenoid, this was hidden away in some trunking but was where the black wire should have been going, with this fixed and all the other wires connected the van burst ( well coughed and smoked ) into life ..!

So again a debt of gratitude is owed to you, the look on the owners face was worth all the effort .

There are numerous other issues that will need to be sorted, the main one being a leak from the diesel pump, it has been suggested that this could be the gasket from the cold start ... and the wipers dont work, I think this is the relay , It had a good earth, good live feed and a working trigger feed, and when i bypassed it the wipers worked, so I will look up the part number for her.

I still have no idea what the bundled group of wires on the rubber mount are for, probably something inside the van would be my guess , but not relevant to the engine wiring so I didnt look any closer.

[Oldiebut goodie]

Cold start lever has an o-ring on the shaft not a gasket. It can be done with the pump on but be prepared for one heck of a lot of swearing as it is worth 20 spanners on the haynes difficulty scale. Put rag underneath to catch the nut that will drop or have a spare ready and also one of those long spring loaded pick up tools! Lever is difficult to get back on to the shaft alone without getting the nut back on. The shaft needs to be held out at the same time as the lever is put back on to get it in the correct position on the shaft and also held out to get the nut back on.(the shaft has free in and out movement) Without space to manoeuvre it is nigh on impossible. A job that if you have done it once in situ you will say never again.

[ELVIS]

Yay!!!!!

Also worth checking O ring on top of pump where the throttle shaft exits the pump top vertically. These are very common to go.

Good on you for being a neighbourly neighbour and good egg, good karma be with you bro

[pionte]

Thanks for the info OBG, it sounds a real pig of a job... Im not going to volunteer myself for this particular one ! Im not a big fan of the oil burners, and try to avoid where possible

The van is now at least running so she can get a garage to come and collect. She needs it moved within the next 2 weeks and I just dont have the time to spare before then.

Thanks Elvis, when I heard how she had been treated it made my blood boil, happy that I could help a young girl out, I think fair play to her for taking on a van that was older than her ! Im not sure I would encourage my daughter to do the same!!