Question Does my wiring look correct?

Jack Rayner

Member
Hi all,

Looking for a bit of advice on some wiring locations in the engine bay of my '51-plate AUA.

First query - I usually reference workshop-manuals.com for part locations and when I was looking today for my gearbox speed sensor and coolant temp sensor I noticed that the conduit around the power feed to the starter motor solenoid is slowly getting chafed by the gear selector plates on top of the gearbox. Upon closer inspection it appears there are some clips on the conduit that aren't clipped into anything and also there's a metal bracket shown in the workshop manual photo that is entirely missing from my car.

Here's a photo of the cable routing:
20200515_191903.jpg

And here are some photos of the bracket I think is missing:
20200515_191925.jpg a2-3615.png

Second query - I'm trying to diagnose a faulty speedometer and @depronman mentioned I should take a look at the cable to the sensor mounted on the gearbox - thanks for the tip! 👍

I can see it buried on the back of the gearbox and the cable looks quite tight in the top of the sensor. I couldn't get a good photo but I wondered if it was due to some odd routing of the cable from where the loom seems to split at the top of the engine. My cable seems to go down underneath the throttle body and if I gently pull on it there appears to be absolutely no slack. Is this correct? And if I wanted to pull the sensor out would the easiest way be to pull the throttle body off?
20200511_191132.jpg

Any hints, tips or guidance is much appreciated.

-Jack
 

timmus

A2OC Donor
I'm trying to diagnose a faulty speedometer
Your car will have the more reliable MK20 ABS system. It does all the ABS processing, but isn't able to output an averaged speed signal to the instrument cluster. Instead, the cluster gets speed information directly from a probe in the differential casing.
Later A2s don't need this speed probe in the gearbox because the MK60 ABS system is able to output speed information to the instrument cluster. The downside is that the MK60 system is less reliable.

Indeed, the corrugated conduits have been routed incorrectly. I wouldn't be surprised if the little bracket had been lost during a clutch change or something like that. The route shown in the diagram is correct. Unfortunately, whilst I have a map of the TDI's engine bay wiring in my head, I'm much less familiar with the under-bonnet area of the petrol A2s. I've never known any A2 looms be as tight as guitar strings from factory, though, so I suspect this is an inadvertent modification by a careless garage.

Cheers,

Tom
 
Last edited:

depronman

A2OC Donor
I’ve done age clutches on the 1.4 petrol
I concur with Tom some one as not fitted the bracket when either doing a start motor change or clutch change

As for the wiring to the speedo sensor there is normally about 3”of play in the loom so some one as routed this incorrectly. Leading me to thing a clutch changes by a garage who don’t know the A2 very well is the most likely culprit

I would try to sort out the loom wiring
If you need some movement to allow the connector to be removed then remove the dog bone mount from the bottom of the gear box you can then rotate the gearbox an not to get some cable slack

Paul


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Jack Rayner

Member
Thanks for the responses, guys. :)

Indeed, the corrugated conduits have been routed incorrectly. I wouldn't be surprised if the little bracket had been lost during a clutch change or something like that. The route shown in the diagram is correct. Unfortunately, whilst I have a map of the TDI's engine bay wiring in my head, I'm much less familiar with the under-bonnet area of the petrol A2s. I've never known any A2 looms be as tight as guitar strings from factory, though, so I suspect this is an inadvertent modification by a careless garage.
I'll see if I can source the bracket, if not I might get a small piece of metal that I can mount to the original location. I'll also reroute the cable and then zip tie it to the bracket to hopefully avoid any future wear.

As for the wiring to the speedo sensor there is normally about 3”of play in the loom so some one as routed this incorrectly. Leading me to thing a clutch changes by a garage who don’t know the A2 very well is the most likely culprit

I would try to sort out the loom wiring
If you need some movement to allow the connector to be removed then remove the dog bone mount from the bottom of the gear box you can then rotate the gearbox an not to get some cable slack
I'll take a look at doing that as the cable is very tight and it appears to be pretty buried in there. It's making me wonder what other things they may not have put back correctly :oops:
 

Jack Rayner

Member
@depronman you wouldn't happen to have some photos of where the starter cable is meant to be? I can't work out which hoses I need to route it under. I think it might need to go across the top of the gearbox and then basically alongside the EGR pipe.

Cheers,
Jack
 

Jack Rayner

Member
I tried for a couple of hours to route the cable across the top of the gearbox and through to the front, I explored going under and over various hoses and linkages but I just couldn't get it to sit right. :(

The cable was either sitting on top of one of the gear selector cables or it was too short by the time it reached the front of the engine. I think realistically I would need to start pulling hoses off to get better access or maybe it would be easier to route if the car was up on a ramp; so for now I have placed the cable back in the original, incorrect position and used a zip tie to stop it getting in the way of the gear selector mechanism. Whilst I had the cables off I was also able to rotate the other cable down slightly so that it's no longer being rubbed. Once the car is all MOTed and mostly fixed I'll revisit this.

Oh, and it turns out there is a little more slack on the cable to the gearbox speed sensor after moving the cables around as someone had zip tied the loom to the bracket too far back, pulling all of the cables. It still doesn't function however... :D
 

depronman

A2OC Donor
I’m afraid I don’t have any pictures nor do I have a 1.4 petrol available atm to take any

Paul


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Davidkinton

Member
I think looking at your photo, that you are missing the cover which goes over the starter on a 1.4 petrol. They are quite difficult to fit, so lots of mechanics don’t bother. The cover does keep the cables out of the way of the gearbox tower though. The spare stud above the starter is where I connected my earth cable. Are you sure the picture you have is of the 1.4 petrol and not the diesel starter motor?


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GMH499

Member
I think looking at your photo, that you are missing the cover which goes over the starter on a 1.4 petrol. They are quite difficult to fit, so lots of mechanics don’t bother. The cover does keep the cables out of the way of the gearbox tower though. The spare stud above the starter is where I connected my earth cable. Are you sure the picture you have is of the 1.4 petrol and not the diesel starter motor?


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Is this the plate/cover that the pre-cat O2 sensor slides into? Mine is hanging around held up by some wiring. I had to fit a new sensor for the MOT, but can't make out where this plate attaches. I've just held it away from vulnerable areas by ties. 2001 1.4 AUA.
 

Davidkinton

Member
Is this the plate/cover that the pre-cat O2 sensor slides into? Mine is hanging around held up by some wiring. I had to fit a new sensor for the MOT, but can't make out where this plate attaches. I've just held it away from vulnerable areas by ties. 2001 1.4 AUA.
No, it’s a plastic cover that fits over the entire starter motor. It had been butchered on my car because it is awkward to fit. I got one from another member and replaced it when I refurbished the starter motor.


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GMH499

Member
No, it’s a plastic cover that fits over the entire starter motor. It had been butchered on my car because it is awkward to fit. I got one from another member and replaced it when I refurbished the starter motor.


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Thanks. I'm still finding my way around the car. Trying to do most jobs myself, though I did concede on the suspension arms, trailing bushes and driveshaft boots.
 
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