Need a bit of old school diagnostic help

[eltax91]

EDIT: THREAD UPDATED ON PAGE 2 - 15:32, Sunday 5th

Hi all

Sat in the garage, for mud plugging weekend fun, is my Defender 90, 200 TDi. I have not had a chance to take it out recently, so the battery is flat. I have stupidly loaned my trickle charger to a mate, who is working away in the states. The truck has modified seats, so battery access is difficult (under the fixed-in seat), however, it has an Anderson plug on the front wired directly to the battery, via an isolator in the cabin. There is also a handy voltmeter in the cab.

Anyway, fast forward to this morning, I plugged my (beefy) jump cables into the Anderson plug and attached the other end to my Diesel Octavia. The cabin voltmeter showed 13v, but the landy would just turn very slowly, but not fire. I got help to tow start the landy and it kicked into life! I went for a 40 minute run, no lights, no heaters, nothing. I switched it off after the run and it still wouldn't start, at first a slow whir, then, each turn of the key produces just a "click". I am assuming the click is the starter engaging, but not turning?

It still won't jump start (even when connected and showing 14v), but will tow start. I have an adapter for the Anderson plug, the multimeter shows 12v across this plug.

So, is the starter knackered? Or did I not run it for long enough to get some juice into the battery? Or could my battery just be goosed after the 3 weeks (ish) of no use and no longer accepting a charge? Maybe the alternator is dead, but surely it would still jump start if that was the case?

Any thoughts greatly appreciated. I'm off Green (white) laneing tomorrow, so it'll have to run for the full 4 hours, if that doesn't charge the battery enough to start under it's own steam, i'm guessing nothing will?!

any help greatly appreciated

Edited by eltax91 on Sunday 5th February 15:32

[P I Staker]

At 13V I would expect it to start with no bother.

Get a piece of wood and a hammer and give the starter a couple hits, the solenoid might be sticking.

[eltax91]

P I Staker said:

At 13V I would expect it to start with no bother.

Get a piece of wood and a hammer and give the starter a couple hits, the solenoid might be sticking.

Thanks for the advice. I wondered if the starter was sticking. It's weird though, if the starter solenoid was sticking, would the engine even attempt to turn? It does turn (sometimes), albeit very slowly.

[CoolHands]

if the battery was totally flat you might have killed it. New battery.

[Superhoop]

That sounds more like a poor earth. Check voltage of the Anderson plug, but using the engine as a ground.

If it's used as a mud plugger, it could be that the starter motor is full of mud?

[eldar]

What is the voltage when cranking the engine? Could be the battery is knackered.

[Fleckers]

i would say battery is fubar

its taking the power from the other car but as its fubar its not dealing wiht the charge

[P I Staker]

eltax91 said:

Thanks for the advice. I wondered if the starter was sticking. It's weird though, if the starter solenoid was sticking, would the engine even attempt to turn? It does turn (sometimes), albeit very slowly.

Im not sure, give it a go and see what happens, worth a try before just jumping to the conclusion the battery is knackered.

[eltax91]

P I Staker said:

Im not sure, give it a go and see what happens, worth a try before just jumping to the conclusion the battery is knackered.

Fair shout, it will be getting a good whack with the hammer tomorrow, before I go out.

[1point7bar]

The click is more likely the solenoid.

You would need 200+ Amps to Cold Crank the engine. Most jump leads won't deliver that good a circuit and need some help from the battery.

[DuckDuck]

Bad connection/ Bad earth as above. Battery may be fubar anyway but should start ok with good quality jump leads. defo sounds like connection

[DuckDuck]

When I say bad connection I mean on the high current side not the solenoid wires as these are obviously working ok. starter and solenoid imo are fine

[blaineuk]

Battery is fecked, cold weather, no use, new battery required.

[davepoth]

I would check the earthing first, as it's cheap. With the battery as charged as you can get it, clip a jump lead to the engine block, and then the other end to a bit of clean steel on the chassis (which I assume is the earth on a Defender?) and see if that makes a difference.

[eltax91]

davepoth said:

I would check the earthing first, as it's cheap. With the battery as charged as you can get it, clip a jump lead to the engine block, and then the other end to a bit of clean steel on the chassis (which I assume is the earth on a Defender?) and see if that makes a difference.

Cheers for the advice, I will try this tomorrow after going laneing, should be as charged as possible after 4 hours non stop running! So, clip cable to block and chasis, if that starts it, does that point to a particular earth?

Also, could anyone tell me where to find the earth points on the defender and what to check for connection wise?

[davepoth]

Looking into this a bit more I think the starter may have its own earth. It'll be a big fat braided cable leading from the starter to somewhere (internet says bellhousing). If that's the case, jump lead from the starter earth to the chassis should do the trick.

If that does do it, the best thing to do is to replace the earth lead, making sure that the bolts and the metal it contacts on the starter and whatever it earths to are good and clean.

[trevt]

Hang on, battery may not be fecked! Think this thro - bump started, ran and then wouldn't restart. If the battery was dead it wouldn't have keep running too well. Plus Octavia wouldn't bump it in first place.
If it's been sitting for a while might just be a deep discharge that hasn't been fully recovered...in that state a quick charge wouldn't sort it.

Suggest a 24 hour trickle charge or (if no charger) bump start it, leave it ticking for a good hour or so and then park at top of a hill until you've driven a few hundred miles! Alternatively a cheap trickle charger might be better than a new battery.

What's the cranking amps on the Octavia battery compared to the Landie

[littleredrooster]

The static voltage of a battery tells you very little. It may have 13V, but as soon as you connect the starter motor into the circuit, it may well drop substantially. Anything less than about 9V when cranking means that the battery is either not charged fully or goosed.

Trickle-charge the battery for 24 hours and try again. Measure the cranking voltage as above. Or if it still just 'clicks', it's time for a new one.

I suspect that after being flat for three weeks, it will be NFG.

After starting the engine, drive it or let it run for 10 minutes or so and measure the battery voltage again; it should settle at 13.8-14.5V at a fast tickover. Anything less means it's not charging properly.

[eltax91]

Cheers all for advice. My trickle charger is with a mate, if the run doesn't do it, then I will check the starter earth with a jump cable and spin it.

During normal running/ fast idle, the voltage is 14. Whilst idling its 13v. So, if the battery isn't goosed, then it should charge I guess!

Thanks to the last poster, when cranking, the voltmeter in the cab does drop down below 12v, so perhaps battery is deep discharged.

If I can't get my charger back, may go on the hunt for a cheap one and see how it goes.

[deeen]

I reckon new battery, the old one is so dead that the alternator can't charge it, but provides enough charge for the car to run (no spark plugs so the engine is not using power to run - just ancillaries). What do the headlights look like when it is running? Dim when idling? And in my layman's mind, the jump leads are trying to charge the failed battery with not enough energy beyond that to turn over a cold diesel.