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Zagato
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Member Since: 08 Jan 2011
Location: Billingshurst West Sussex
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Flat Battery, Bumping a Diesel!
Wife's' SAAB has a flat battery, the short drive she does to work and back drains the battery it never gets a chance to charge up properly. I haven't any jump leads (is it negative to neg first?) so was going to bump start it if I can manoeuvre it. I have bumped started it before but doesn't it Censored up the cat?
Post #122104 7th Feb 2012 5:45pm
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LR90XS2011



Member Since: 05 Apr 2011
Location: bickenhill
Posts: 3615

United Kingdom 2011 Defender 90 Puma 2.4 XS CSW Galway Green
Zag
People do generally connect the negative first but I dont believe there is any good reason why the positive should not be connected first
re bump starting Ive no idea why this would cause a problem if you have some power for all the other bits and bobs like the fuel pump as essentially you are just replacing the starter motor with some kinetic energy DEFENDER 90 TDCI XS,

I hope everyone is well and your land rovers make you happy


Last edited by LR90XS2011 on 7th Feb 2012 6:34pm. Edited 1 time in total
Post #122108 7th Feb 2012 5:54pm
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custom90



Member Since: 21 Jan 2010
Location: South West, England.
Posts: 19579

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Just jump start it and it'll be fine just use the normal starting procedure for a diesel once the jump leads are connected. I wouldn't try and push it and put it in gear 'bumping it' not in a diesel anyway. Mainly because a diesel requires warming by the glow-plugs first.
Post #122111 7th Feb 2012 6:19pm
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blackwolf



Member Since: 03 Nov 2009
Location: South West England
Posts: 16886

United Kingdom 2007 Defender 110 Puma 2.4 DCPU Stornoway Grey
If the vehicles are neg earth you're better off connecting pos first. Then you can make the final neg connection to an earth point away from the battery. This is safer since if either battery is gassing due to charging there is less chance of a spark causing a hydrogen explosion and at the least covering you in sulphuric acid (I have seen a battery blow up and it is not at all nice). For the same reason on pos earth you would connect neg first.

The cat thing I think is one of those urban legends. If the engine flooded and unburned fuel got in the cat it would be poisoned. This could happen with a bad misfire on a petrol engine but is rare. Despite what makers say I have never heard of cat damage from jump, bump, or tow starting, or from running out of fuel. I think a more realistic problem would be a failure to bump start due to some electronic sequencing problem, such as the ECU not playing if it hasn't had a cranking signal.
Post #122117 7th Feb 2012 6:30pm
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bpman



Member Since: 21 May 2008
Location: Oslo
Posts: 8069

2008 Defender 110 Puma 2.4 SVX Station Wagon Santorini Black
Re: Flat Battery, Bumping a Diesel!
Zagato wrote:
I have bumped started it before but doesn't it Censored up the cat?


it does if the stupid cat is still on the drive Rolling with laughter

wow - you've had a bad day mate ... what you need is some Scottish Wine, the love of a good woman and a winning lotto ticket
Post #122139 7th Feb 2012 7:23pm
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custom90



Member Since: 21 Jan 2010
Location: South West, England.
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Re: Flat Battery, Bumping a Diesel!
bpman wrote:
Zagato wrote:
I have bumped started it before but doesn't it Censored up the cat?


it does if the stupid cat is still on the drive Rolling with laughter

wow - you've had a bad day mate ... what you need is some Scottish Wine, the love of a good woman and a winning lotto ticket


Just not to much or she'll take the lot Whistle
Post #122142 7th Feb 2012 7:25pm
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Zagato
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Member Since: 08 Jan 2011
Location: Billingshurst West Sussex
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I'm already on the whiskey Steve Wink Life is looking rosy already....hic! Very Happy but the love of a good woman is not a bad idea Wink Got anyone in mind Laughing
Post #122153 7th Feb 2012 7:47pm
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WarPig



Member Since: 05 Dec 2009
Location: Sheffield
Posts: 1748

England 1996 Defender 110 300 Tdi USW Bonatti Grey
Re: Flat Battery, Bumping a Diesel!
Zagato wrote:
so was going to bump start it if I can manoeuvre it.


Well done on spelling 'manoeuvre' correctly Very Happy For me its one of those difficult words to spell Embarassed

Is there any harm in doing neg to neg & pos to pos? When Ive jumped cars often one of the terminals is impossible to get to.
Post #122168 7th Feb 2012 8:26pm
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Glynparry25



Member Since: 16 Feb 2009
Location: Miserable Midlands
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Wales 2009 Defender 110 Puma 2.4 XS DCPU Tonga Green
Here is a test you guys can try.......

Put the negative cable on (Neg- Neg).

Put the positive cable on either vehicle.

Touch ANY metal part of either vehicle with the other end of the positive cable......... and watch the magic sparks show!!!

Same reason why you take the negative terminal off a battery first. You have to keep the circuit as small as possible.

I worked with a guy who had just got married... he was taking the batteries off a 4 ton truck (24v). He decided to take the positive off first as it was easier to get to..... as the nut 'cracked' his hand touched the truck chassis...... 24v shorted from the positive terminal down the spanner, through his wedding ring to chassis. Half the ring was welded to the spanner and the other half had to be pulled off his finger with a whole load of melted skin. It took him 3 months to be back fully fit and was still getting plastic surgery on his finger 6 months later.

Since then I have religiously taken the negative terminal off first....... and never got married (gotta be sure!!)

Glyn Dog Sheep
Post #122192 7th Feb 2012 9:14pm
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Dave-H



Member Since: 08 Feb 2011
Location: Surrey
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England 2007 Defender 90 Puma 2.4 HT Tonga Green
Yep, as Glyn said ...

It's ALWAYS pos to pos first with jump leads ... then neg lead to a good earth point [not battery terminal] on both vehicles.

Also helps to start the good vehicle and let it run for a few mins before tryin to start the flat vehicle ... this lets the flat battery recieve a drop of charge from the donor vehicle.



And if taking battery leads off a battery - NEG FIRST ! Guns and Landrovers .... anything else is irrelevant.
Post #122197 7th Feb 2012 9:18pm
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custom90



Member Since: 21 Jan 2010
Location: South West, England.
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I think the reason why some people are tempted to take off positive first is due to it being one of two things. Either positive easier to access or the positive terminal being easier to remove than the negative. I personally think the Defender battery terminals could do with a better design to tighten up better and 'clamp' around the battery posts better.
Post #122226 7th Feb 2012 10:20pm
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wslr



Member Since: 18 Jul 2010
Location: Wellington, Somerset
Posts: 581

United Kingdom 
Re: Flat Battery, Bumping a Diesel!
Zagato wrote:
Wife's' SAAB has a flat battery, the short drive she does to work and back drains the battery it never gets a chance to charge up properly. I haven't any jump leads (is it negative to neg first?) so was going to bump start it if I can manoeuvre it. I have bumped started it before but doesn't it Censored up the cat?


Provided it is a manual box, just drag it down the road behind the Puma, kicking a screaming (the SAAB, not the missus, mate). Part depends how advanced the electronics are on the SAAB.

Jump starting, RTFM to find out how SAAB suggest doing it. There may be specific jumping points, like of the L322.
Post #122256 7th Feb 2012 11:46pm
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bpman



Member Since: 21 May 2008
Location: Oslo
Posts: 8069

2008 Defender 110 Puma 2.4 SVX Station Wagon Santorini Black
Zagato wrote:
I'm already on the whiskey Steve Wink Life is looking rosy already....hic! Very Happy but the love of a good woman is not a bad idea Wink Got anyone in mind Laughing


Post #122277 8th Feb 2012 8:28am
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Zagato
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Member Since: 08 Jan 2011
Location: Billingshurst West Sussex
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She positively needs jumping Very Happy

Thanks for your replies folks, wish I had read them earlier, took the positive off first didn't I Rolling Eyes I always forget which way to do it! Battery now charging in the kitchen Thumbs Up
Post #122307 8th Feb 2012 12:29pm
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blackwolf



Member Since: 03 Nov 2009
Location: South West England
Posts: 16886

United Kingdom 2007 Defender 110 Puma 2.4 DCPU Stornoway Grey
Zagato wrote:
... Battery now charging in the kitchen Thumbs Up


Do remember that the battery may well gas during charging, and that the gas that comes off is hydrogen. Think "Hindenberg" disaster, think "bang", big fire and battery acid all over anything that survives the explosion and fire.

Remember if it is in the kitchen to leave the door or window open. You really are better off charging it outside.

I used to charge batteries indoors too, until the day I was standing beside a Volvo-BM LM640 loading shovel when the battery, which was on charge, detonated. Fortunately I was standing on the side away from the battery, but we were picking up bits of shattered battery from 30 yards away, and everything within about 30 feet on that side of the machine was dripping acid. Fortunately it was outdoors and there was no fire, but it was an eye-opener. It really isn't worth the risk.
Post #122328 8th Feb 2012 2:00pm
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