Ground Wires

[rayf3262]

hmmm....very odd Ray, because I am 99% sure its disconnect the bottom end, as that was the end that attached to the starter!! I wonder if its touching the starter, and if so, would that cause any anomalies??

next job is to insulate both ends or attempt to remove....

Just re read your original post.
If you are reading 43 or so mV on the redundant cable, then yes it's almost certainly disconnected, so don't worry, but do check it to be sure.
The test meter you are using will be very sensitive and the voltage you are seeing is, in all probability just a small induced voltage from the other wiring in close proximity.

 

[clivvy]

hey chaps. I havent had much time at all the last few weeks to look at this issue. I took it out tonight for the first time, just a short couple of miles round the back to the petrol station, and out the streets. Was fine, right up until I parked up at home, and blipped the pedal, then the MiL came on briefly....grrr....what the flip is wrong with my car? Its obviously electrical, but I just cant place what it is.

I want to renew the main negative battery wire, can anyone advise me on this? Where can I get a new one, and what about this join under the washer bottle?

I am also going to give the ground wires another good clean, and fit some B&Q "shake proof" internal washers, are these suitable?

after confirming (i think) I have continuity at the pedals, I cant figure out the problem unless I have two duff accelerator pedals....!!

 

[clivvy]

ok #sigh#

removed the entire loom from the engine bay, well, the section that connects the ground wires, gear box etc.

removed the old battery cable, and checked all wires while I was at it, all ok. Put it all back together with very numb fingers, and as I was re attached the negative to the ground point under the water bottle, the broke broke.

anyhoo, carried on and when I came to put ignition on, the glow light stays lit but dim, and some other dash bulbs don't work, MiL light on. car starts ok. Could this just be because I haven't re attached the negative to the inner wing?

If so, that's fine, I will just drill a new hole or extract the broken bolt.

 

[rustic]

ok #sigh#

removed the entire loom from the engine bay, well, the section that connects the ground wires, gear box etc.

removed the old battery cable, and checked all wires while I was at it, all ok. Put it all back together with very numb fingers, and as I was re attached the negative to the ground point under the water bottle, the broke broke.

anyhoo, carried on and when I came to put ignition on, the glow light stays lit but dim, and some other dash bulbs don't work, MiL light on. car starts ok. Could this just be because I haven't re attached the negative to the inner wing?

If so, that's fine, I will just drill a new hole or extract the broken bolt.

Don't forget all the panel lights etc will probably be earthed to the metal work behind the dash etc, so the return requires the body earthing to the engine, chassis etc.

I wouldn't run the engine without this wire grounded as you may find a smaller cable is carrying all the return current and may over heat or worse.

Hence the dimmer lights, :doh

If the ecu doesn't have a proper earth, you might destroy it..

 

[clivvy]

ah ok Rustic, I will get the earth connected properly tomorrow!

 

[cleangreenm/c]

cable to s/mtr?

some years ago a work mate tried changing a starter mtr with out removing any battery conections HE allso bid NOT remove his expandable watch the result ----------- 3days in hospital and aburn the whole way round hiswrist that to this day looks horrifick roy

 

[clivvy]

some years ago a work mate tried changing a starter mtr with out removing any battery conections HE allso bid NOT remove his expandable watch the result ----------- 3days in hospital and aburn the whole way round hiswrist that to this day looks horrifick roy

ooooooouch......poor guy.

 

[clivvy]

well....little update. The car isnt broke thank god, but I did have to re drill a new hole for the earth from battery. I then fitted anti vibration washer to each earth point on the inner wing, and on the positive battery (after sanding down the area first, then greasing afterwards).

I still have the glow relay light dim, and error, so I hooked up the computer and found it was the coolant sensor, and the pedal. so I re checked the engine bay, found one plug not fully fitted, so I pushed it in, engine jerked then settled. Went back to computer, all faults cleared, dash looks perfect.

Took for a test drive, all good so far!!! Havent been far, but got car to running temp and put under some load plus used 4 wheel drive, again, no issues with the pedal.

just a couple more longer test drives, and fingers crossed, I have finally fixed it!!!

 

[rayf3262]

well....little update. The car isnt broke thank god, but I did have to re drill a new hole for the earth from battery. I then fitted anti vibration washer to each earth point on the inner wing, and on the positive battery (after sanding down the area first, then greasing afterwards).

I still have the glow relay light dim, and error, so I hooked up the computer and found it was the coolant sensor, and the pedal. so I re checked the engine bay, found one plug not fully fitted, so I pushed it in, engine jerked then settled. Went back to computer, all faults cleared, dash looks perfect.

Took for a test drive, all good so far!!! Havent been far, but got car to running temp and put under some load plus used 4 wheel drive, again, no issues with the pedal.

just a couple more longer test drives, and fingers crossed, I have finally fixed it!!!

Fingers crossed,...your re-work of the ground points and other connectors etc. seems to have put you on the right track. Here's hoping!

 

[clivvy]

Fingers crossed,...your re-work of the ground points and other connectors etc. seems to have put you on the right track. Here's hoping!

Cheers Ray, I just couldn't have done it without everybody's input, especially yours. Even if it breaks again, I feel I have learnt a lot.

 

[rustic]

I'm pleased your sorted, looks like this is the answer..
Well done..:thumb2:thumb2

 

[clivvy]

I bloody damn well knew it.

Did 15 mile yesterday, drove to work via town this morning, no problems. Come out to it this evening to go home, and reversed out, bam, MiL on loss of power again. Turned it off and back on, still the problem, turned it off for a few seconds more, all ok and drove home fine which is about 4 mile. Weather was damp, misty and nothing else occurred with the car...

what the chuff is wrong with my car? I really cant be doing with random issues like this. How can an electrical issue be so random? If it truly is the pedal, I changed that already (ok not a new one but still)

??



I am getting fed up now.

 

[chatterbox]

Just a few thoughts, is there any way you can check to ensure the connectors which are in either end of the connector to the pedal are all a good tight fit, maybe one of the connectors is just a poor fit?
It is possible that even though the connector clips in place, it does not mean that all the males and females inside are well connected.

I mention this just because when you disconnected and then reconnected all the wiring it all seemed to be working for a while.

Also, it is a small possiblity that the earth to the pedal switch itself might not be a good earth.
Again, you could do a volt drop test on the earth path just to make sure by backpinning it with ign on and off and moving the pedal, then do same on the feed out to see how it varies as the pedal is moved.
Also make sure what voltage is being supplied to the pedal exactly!!! is it getting the correct voltage in and out and how the voltage varies with movement of pedal on the feed out to ecu.
Do you notice any significant miss in the voltage out as pedal moves.
Would be a lot easier tracking on an ocillascope though if you know anyone who has one?
I notice you mention both the pedals you have are not new but you are getting exact same results whichever you try.
If you really want to track it down I am sure someone here can tell you which pin is the correct pin to test at the ECU end to doubly make sure.
Hope some of that might help in this elusive problem.

Just bit more info.
If probes too big to backpin, try using a paperclip to push into wires where go into connector ( you sometimes have to be firm with paperclip as it can be a tight fit as rubbers to seal can be a touch tough to push it though) and then use croc clip on end of probe to clip onto, only use one paperclip and do not try to do two at same time as clips could touch and you dont want that, no no no, not at all. but backpinning can sometimes find faults where other means might miss it

 

[clivvy]

thanks mate, I am pretty fed up as I have spent a long time with this.

I will re check the pedal connectors and wires, and stay focussed on that for now. Last I checked, the ground wires were ok. This may not be relevant, but when I got the car, both small ground wires on the engine block were connected further forward on the block, along with the engine ground. Could be this has been a very long existing fault.

has anyone got a picture of their wiring? I would really liek to see if the ground wires i have are correct, and in the correct place.

 

[chatterbox]

As you are aware ground wires are pain in butt, but, you can always fit another earth wire (same size cable as main positive) straight to the back of the starter moter with star washers to help contact and then connect to the negative on battery, this assists with starting and any engine earths.
Lots better than any earths attatched to top of engine block.
Also connect a same size cable from earth connection on inner wing to main bulkhead panel behind pedals (you will have to drill another hole) again using star washers, this ensures good earths to things like dash panels, radios, ecu's and most of electrics that are earthed to car body.
I have found lots of little faults can be caused by bad earths, even once found a golf with all the earths burnt out where bolted to car bulkhead after some car breakdown feller had tried jumpstarting it with 24 volts, after spending six hours with a replaced ecu which had also burnt out due to this fault but which had run for a day, left customer to try to prove and sue was breakdown fellers fault, cost him a complete new wiring harness.

 

[rayf3262]

a jump lead (or similar) temporarily connected connected between suspect ground points may help narrow down such problems...

 

[clivvy]

thanks guys I will try re testing the ground points too. Maybe I do need to re position the existing earths, I just cant seem to figure out what the issue is-bad grounding, or something else. With the issue being so random, how on earth do you pin point that?

 

[chatterbox]

random faults are usually always hardest to find, is always test and try, try, try and then test and try again till it goes away, its never easy.

 

[macabethiel]

old wires showing voltage

Could just be inducted current showing a small reading. If its a full reading there might be a connection hidden in the loom wiring !

 

[clivvy]

ok, here is a thought.

you know the panel, that runs along the lower front of the windscreen-where the wipers slot through? well, mine doesnt have any fixings at all, so obviously it has been off at somepoint, and, so has my dash. SO, is it possible that part of the loom is accessible through there, or, could it be i have a water leak through there??

i am clutching at straws.

I have had weird intermittent fault since I bought the car, but of course the accelerator pedal is stopping me from driving, whereas before the car would just jolt a bit.