Car won’t start - battery fine.
Discussion
Still trying to find someone with jump leads. In the meantime, I looked at the connections again.
Thick black cable from the -ve on the battery is connected to a tab on the "dome" containing the suspension strut. There's another black cable connected to the same dome which disappears under the fuse box and continues under the battery. I can't tell where it goes after that.
Nothing else to report!
Thick black cable from the -ve on the battery is connected to a tab on the "dome" containing the suspension strut. There's another black cable connected to the same dome which disappears under the fuse box and continues under the battery. I can't tell where it goes after that.
Nothing else to report!
Cheapest I could find and are probably rubbish too but come on, you have to borrow some? Go buy a set
https://www.ebay.co.uk/itm/100-AMP-CAR-JUMP-LEADS-...
https://www.ebay.co.uk/itm/100-AMP-CAR-JUMP-LEADS-...
phumy said:
Cheapest I could find and are probably rubbish too but come on, you have to borrow some? Go buy a set
https://www.ebay.co.uk/itm/100-AMP-CAR-JUMP-LEADS-...
Happy to buy some - just won't be able to do it until the weekend.https://www.ebay.co.uk/itm/100-AMP-CAR-JUMP-LEADS-...
Not much to report until I've picked up some jump leads on Saturday, though I'll speak to my local garage guy on Friday anyway.
In the meantime, I discovered that you can test for bad grounds by putting the multimeter into continuity testing mode and attaching the black probe to the -ve on the battery, then touching the red probe on the various earth points. I did this and tested the four ground points that I could find, all of which returned 001, which I believe is as it should be. The engine block, however, which I understand can also be treated as a ground, returned all sorts of random numbers. Maybe the earth cable running from the engine to the chassis is the culprit, but I can only see the end that's attached to the engine block and I can't even reach that.
Anyway, we'll see what Friday brings.
In the meantime, I discovered that you can test for bad grounds by putting the multimeter into continuity testing mode and attaching the black probe to the -ve on the battery, then touching the red probe on the various earth points. I did this and tested the four ground points that I could find, all of which returned 001, which I believe is as it should be. The engine block, however, which I understand can also be treated as a ground, returned all sorts of random numbers. Maybe the earth cable running from the engine to the chassis is the culprit, but I can only see the end that's attached to the engine block and I can't even reach that.
Anyway, we'll see what Friday brings.
MitchT said:
Not much to report until I've picked up some jump leads on Saturday, though I'll speak to my local garage guy on Friday anyway.
In the meantime, I discovered that you can test for bad grounds by putting the multimeter into continuity testing mode and attaching the black probe to the -ve on the battery, then touching the red probe on the various earth points. I did this and tested the four ground points that I could find, all of which returned 001, which I believe is as it should be. The engine block, however, which I understand can also be treated as a ground, returned all sorts of random numbers. Maybe the earth cable running from the engine to the chassis is the culprit, but I can only see the end that's attached to the engine block and I can't even reach that.
Anyway, we'll see what Friday brings.
Mmmmm, it don't work like thatIn the meantime, I discovered that you can test for bad grounds by putting the multimeter into continuity testing mode and attaching the black probe to the -ve on the battery, then touching the red probe on the various earth points. I did this and tested the four ground points that I could find, all of which returned 001, which I believe is as it should be. The engine block, however, which I understand can also be treated as a ground, returned all sorts of random numbers. Maybe the earth cable running from the engine to the chassis is the culprit, but I can only see the end that's attached to the engine block and I can't even reach that.
Anyway, we'll see what Friday brings.
Resistance tests are meaningless as there's no load on the circuit being tested, many circuits will pass a resistance test yet fail a volt-drop test under load
Volt-drops are what it's all about
Measure voltage between 2 points when under load
Voltmeter connected between battery negative and engine block, turn key to crank position, 0.25 volts maximum should be shown on the voltmeter, any higher reading points to a bad engine earth
Same volt-drop test can be carried out on the battery positive cable to starter motor
Voltmeter connected between battery positive and starter positive, turn key to crank position, 0.75 volts maximum should be shown on the voltmeter, any higher reading points to a bad positive cable
Note higher volt-drop expected at positive cable, 0.75 volts max
Just had the guy from the garage out...
Booster pack on battery: Nothing.
Jump lead from -ve to block: Nothing.
Attempt to bump start: Nothing.
He's now arranging to get it towed so he can get it on his ramp.
Odd how a car can be parked working fine and a month later, be completely dead, even though the battery is fine!
Booster pack on battery: Nothing.
Jump lead from -ve to block: Nothing.
Attempt to bump start: Nothing.
He's now arranging to get it towed so he can get it on his ramp.
Odd how a car can be parked working fine and a month later, be completely dead, even though the battery is fine!
Sheepshanks said:
On the upside, at least it has a definite fault. It's a nighmare when these things are intermittant.
Definitely. I was concerned that it would suddenly and inexplicably work again and then I'd be worried that the fault would return when I'm out somewhere. I'd sooner something is broken and is then fixed, even if it means spending some money.Garage called and said they couldn't find a fault anywhere, so maybe the key's not talking to the immobiliser - have I got any more keys? I was already using the spare master as the main master had broken - it was one of those fancy (but relatively fragile) ones with a built in torch and it had disintegrated years ago when I used excessive force on a stiff lock. Funnily enough I'd bobbed into a BMW main dealer last weekend for a quote to get that replaced. Anyway, I went down to the garage at lunchtime with the valet key and bingo - engine started! Perhaps if the car hadn't been sat for a month, thus prompting thoughts of battery failure or a seized starter, I might have thought to try a spare key in the first place!
Facepalm.
Facepalm.
I didn't think I had another key at the time.
The casing on the main master key had broken apart a few years ago when I used too much force on it in a sticking lock. The spare master key - which I'd be using since - was the one that wouldn't start the car. The other key which I have - the valet key - I mistakenly though that one would unlock the car but not start it. Turns out it does start it but won't open the glove compartment or boot.
At least I know what all the keys do now!
The casing on the main master key had broken apart a few years ago when I used too much force on it in a sticking lock. The spare master key - which I'd be using since - was the one that wouldn't start the car. The other key which I have - the valet key - I mistakenly though that one would unlock the car but not start it. Turns out it does start it but won't open the glove compartment or boot.
At least I know what all the keys do now!
MitchT said:
The other key which I have - the valet key - I mistakenly though that one would unlock the car but not start it. Turns out it does start it but won't open the glove compartment or boot.
At least I know what all the keys do now!
The valet key is for a parking valet to use - you obviously don't frequent the right sort of places. At least I know what all the keys do now!
Gassing Station | Home Mechanics | Top of Page | What's New | My Stuff