Earth Cable (Rocker cover)

I've had a few issues with the rev counter and dash lights not working I believe this to be due to an earthing problem. I found 2 earth cables on the rocker cover, the back one is fine and intact however this brown wire located further down is completely broken off. I can't find the other end that it attaches too to know where it's supposed to lead to. 

I want to replace the earth cable and hopefully fix the rev counter and dash light problem. Can anyone tell me where this cable goes to from the rocker cover as I've got no idea, im guessing it goes to the fuse box or the hooks above somewhere but some guidance would be great? Any pictures and advice would be greatly appreciated. Could this also solve my fuel gauge not working? Thanks 

If it was an earth its somewhat redundant as there is a great big FO earth cable direct from battery to the chassis and gearbox/gearbox mount

the rocker cover small braided wire should go to the coil bracket

for the dash lights twiddle the rheostat on the headlight switch

Early-1800 said

If it was an earth its somewhat redundant as there is a great big FO earth cable direct from battery to the chassis and gearbox/gearbox mount

the rocker cover small braided wire should go to the coil bracket

for the dash lights twiddle the rheostat on the headlight switch

Thanks where about is the coil bracket

The coil brkt is normally on the bulkhead :



Realistically, the earth strap/cable can be fixed to any part of the bodywork, the whole body shell is the earth 👍🏽

The earth cable from the rocker cover to the ignition coil bracket is more important than it looks.

Believe me I found out the hard and expensive way. Without this the engine could just die at high speeds which is what kept happening to me.

Because of this I covered many embarrassing miles on the back of an AA flat bed and paid an auto electrician a lot of money for nothing. He doubled up on the earthing everywhere which had little effect, when all I needed was this piddly little earth wire from the coil bracket to the rocker cover.

You see I had a pre 83 carb engine with points and condenser which did not have or need this earth wire, but then I upgraded to a post 83 engine which has electronic ignition which does need this wire (as do you), but I did not know about this to my detriment.

AverageCitizen said

Early-1800 said

If it was an earth its somewhat redundant as there is a great big FO earth cable direct from battery to the chassis and gearbox/gearbox mount

the rocker cover small braided wire should go to the coil bracket

for the dash lights twiddle the rheostat on the headlight switch

Thanks where about is the coil bracket

I do already have a flat cable which is black connected to that from the rocker cover is there supposed to be 2 in the same place then?

jazzydog said

The coil brkt is normally on the bulkhead :



Realistically, the earth strap/cable can be fixed to any part of the bodywork, the whole body shell is the earth 👍🏽

I do already have a flat cable which is black connected to that from the rocker cover is there supposed to be 2 in the same place then?

No, just but one.  The other may have been a sender wire, I wouldn't worry too much about it, unless you can see the other bit as it may be inside of a sheath near it.  

Briano1234 said

No, just but one.  The other may have been a sender wire, I wouldn't worry too much about it, unless you can see the other bit as it may be inside of a sheath near it.  

I will check the sheath now, however I just had a light bulb moment, Could this broken earth wire possibly be for the Extra VDO oil pressure gauge that i have that doesn't work 

AverageCitizen said

Briano1234 said

No, just but one.  The other may have been a sender wire, I wouldn't worry too much about it, unless you can see the other bit as it may be inside of a sheath near it.  

I will check the sheath now, however I just had a light bulb moment, Could this broken earth wire possibly be for the Extra VDO oil pressure gauge that i have that doesn't work 

no becasue its simply connected to an engine block stud not an oil pressure sender

zod said

The earth cable from the rocker cover to the ignition coil bracket is more important than it looks.

Believe me I found out the hard and expensive way. Without this the engine could just die at high speeds which is what kept happening to me.

Because of this I covered many embarrassing miles on the back of an AA flat bed and paid an auto electrician a lot of money for nothing. He doubled up on the earthing everywhere which had little effect, when all I needed was this piddly little earth wire from the coil bracket to the rocker cover.

You see I had a pre 83 carb engine with points and condenser which did not have or need this earth wire, but then I upgraded to a post 83 engine which has electronic ignition which does need this wire (as do you), but I did not know about this to my detriment.

That is interesting as I've got at 83 GTI and have never had an earth from the rocker to coil bracket - not had any running issues at all. Am I just lucky?

I've always wondered why it needs an addition earth from the rocker cover when both the gearbox/engine and chassis have full fat cables direct from battery -ve

paceman said

That is interesting as I've got at 83 GTI and have never had an earth from the rocker to coil bracket - not had any running issues at all. Am I just lucky?

What I've discovered is, if you have a points/condenser set up you probably don't need to earth your ignition coil bracket to the rocker cover. I have owned many Mk1s with this set up and like you have never needed it. Which is why I was so confused when I had all the issues after changing the engine to a later one that had electronic ignition with the TCI module. Then you do need this additional grounding but I found out too late.

Even, if you have not had any problems, I would earth the coil to the rocker anyway. It is a quick, inexpensive job and pretty much invisible and could prevent problems in the future. It seems logical after all, as all  high-power components under the bonnet, i.e., alternator, starter, and ignition coil can benefit from having the best grounding possible. Apart from the eradication of all the problems I was having I noticed that my car was more responsive after I earthed the coil, but that could be that it was finally running as it should.

 

While yes the main ground from the Battery to the Frame and Frame to engine/Tranny is a Big Honking WIre there are plenty of Caveats to grounding.

Since I never had a MFA in my rides, I understand that the Missing valve cover to coil bracket is part and parcel to a good running MFA.

I tend to think that the Engineers at VW and Bosch, realized that earthing the engine wouldn't shield all of the Spurious EMF pulses in the Engine compartment from the Firing Mech/ECUs of the Engine.  As in the Coil not being directly tied to the Engine ground as a differential potential of less than a .05mv can wreck havoc on electronics.

Additionally there are Bonding wires from the bonnet to the frame, and brackets to the frame as well.

Originally you would see this as Motorboating in your radio speakers from Spurious EMF pulses in to the final Drivers of your Radio.

In a perfect would it isn't needed, but alas, in VWs it is.
I have seen the Aftermath of bad grounds on the main cables causing other ways for the Starter to find a good ground when you try to start the car.

Through the Clocks via the Speedometer cable.
Through the Clutch Cable.
Through a Senor wire on the Engine.

Don't over think that your OEM ground cables are still good, as they are a Big Honking Wire.

Stranded unshielded wires deteriorate, The individual wires which have no shielding and rely on the Twisting to seal the internal wires can corrode.  when they get dirty they will insulate the connectivity of the strands.

I have seen it on Grounds on my Various Rides over the years, Some Extreme, some subtle.

I think that a good shield can prevent this, but….it can also hide it.

Testing is warranted if you start having issues that are flaky.

Voltage Drop testings of major ground
Frame ground to Coil Bracket resistance.
Using Radiation Apps on your Phone may show you
things as well.

I learned a lot from driving 50's, 60 's, and 70's British Leyland cars, as well as 80's Detroit cars.

I learned a lot from my times chasing down Faulty Electrical things in Airplanes, and Major Network Computer issues.

One of my Favorites that earned me a ton of monies, is when I discovered that ones companies servers were on two separate power sources Transformers outside the Building, leading to a 45VAC volt differential in the Grounds between the servers that were only tied together via the Grounds between terminals.

The Quick work around was a large extension cord running from the one server to Power the other from the same outlet.

Another was finding that a Steam Table in the Commissary of a Prison was causing a spike in the A/C issue of the network.  I discovered it by Accident, as I moved the Steam table away from the Outlet I felt a Tingle in my hand…

I suspect they were trying to electrocute the Inmates to reduce recidivism, Just a Joke, the Warden, and couple of deputies that were tasked with my Security were Wide Eyed, when I used my meter to Prove the point some one could of Fried and die..

Good Grounds are paramount to preventing issues and Spurious things from ruining your day.

BIG CAVEAT.

With the advent of resistored plugs and wires, the need for additional bonding wires was semi negated.  How ever with the invention of Solid state components and different conditions of folks under the hood as in non-resistored wires and or plugs, spurious emf issues could occur, and some of the Cost effective after market radios experienced the PUTT PUTT PUTT of the engine again as it was being filtered in the Final Amp circuits of the Super Hetrodyne am/fm receivers more so when listening to AM over FM and when Cassettes were playing. Which made additional bonding wires useful again.  You can also tell that it is a bonding wire because it was a flat braided cable that was insulated… Wait they would insulate a bonding wire and not the main ground wires?  Who'd of thunk that one for better grounding?