Discovery TD5 auto starting problems.

A bit of an odd one this and I'm a bit lost with modern electronics. Here's the story:

A little while ago the disco developed a habit of not starting again once the engine was turned off unless I disconnected the battery, left it for a while, and reconnected it. At the suggestion of a fellow LR enthusiast I tried my spare key and voila, it started working properly again. I assumed it must have been the battery in the key being too run down to communicate with the immobiliser.

So we come to today and I'm out in town with the missus at the dump with a trailer on (I do take her to all the best places) in a queue waiting to get to the skips. While I'm waiting I switch the engine off and take the net off my trailer then jump back in to move it forward a bit 'cos the queue's moved and it won't start. By that I mean it won't crank, there's nothing. I couldn't get it started again by disconnecting the battery and reconnecting it like the last time it happened. So I had to carry everything in my trailer about 50 yards to the skip while the missus stood at the back of the trailer telling people to go around me. Amazing how many people get so annoyed at so little. Anyway, once I'd emptied the trailer I got a nice guy working at the dump to tow me somewhere out of the way, and my missus went into town with someone who offered to help to get a new battery for the key fob.

Once she returned I changed the battery in the fob and tried again. No joy but after a few attempts at locking/unlocking and just turning the key in the ignition it started. I then decided that I wouldn't turn the engine off until I got home, just in case, but I needed to get fuel on the way home and I couldn't pop the fuel flap without turning the engine off. Sure enough, once I'd fuelled up it wouldn't start again. I was stuck on the garage forecourt thinking dark thoughts about Land Rovers wondering what to do now. I tried the old trick with the battery out of desperation and it didn't work so I was just frantically turning the key in the ignition repeatedly and it randomly started again.

When I got home I tried my other key with a new battery in it and it wouldn't work with that either. Now I can't get it to start at all. All I can say is that when I turn the key to the start position I can hear two relays clicking in sequence, one under the bonnet, and one in the dashboard on the passenger side.

Any ideas? Do I have an evil immobiliser?

I take it you have checked the wiring to your starter motor is sound and tight? You haven't mentioned problems getting into the vehicle or locking/unlocking it. If you have no problems there than I don't think it is a problem with the fob.
If the immobiliser is not working then I doubt you would get any reaction from the vehicle at all when trying to turn the key to start position. The clicking from the relays implies that something is happening, just not very successfully, which implies bad connections, bad starter motor, bad battery, or maybe something else. Try tightening everything up, and that includes finding battery to engine earth leads, and then if that doesn't work, taking a lead from the battery positive to the starter to see if that gets it spinning round. But as this is electrics on a TD5 others with more knowledge will jump in and tell you if I am talking carp or not! I am not certain but it doesn't sound to me like a dodgy ignition switch, but I suppose it could be that too. Surprised to see people on Shetland are as impatient as in the rest of the UK!

Cheers Stan (hope you don't mind me truncating your name). I've checked the starter wiring and it's all secure. I don't have any other problems with the fob functions. Just for the record, I just tried to start it again a minute ago (and I've done nothing except Google the problem) and it started 3 times in a row no messing. It's infuriating. It just seems to wait until the most awkward times to do it.

Shetlanders are a laid back bunch mostly, the impatient ones all seem to live in the town. Apart from Lerwick, the rest of Shetland is very rural.

The internal contacts on the starter erode, there is a kit available, I got mine from a company called x8r ( I think) off eBay.

I had similar problems with mine, intermittent starting issues, all good now after using this repair kit

A quick search on here may be helpful

It's not a difficult job to do, the worst thing to do is locating and loosening the bolt on top of the starter. There is a special place in hell for whoever designed that layout.

Had that problem with my Defender. Totally different symptoms. The starter motor is fine.

Ahh right, hope you get sorted.

You can truncate my handle whichever way you like! I wonder if it is related to weather. i.e. is it more likely to happen when it is damp?
Have you tested all earthing points with a meter set to resistance to see if all are good? I assume so as you said they are all good. You seem very confident the starter itself is good so...
I'd be tempted to temporarily wire in a switch from live to the starter motor relay and see if that functions all the time. If it does you'll know the problem is elsewhere. And you'll be able to get home instead of getting stuck.

As you can unlock the car, it is probably not the fob or the receiver. If you have a diagnostic like Hawkeye or Nanocom you can disable the passive immobilisation to confirm that this is not the issue. It could be an electrical issue or a start motor problem as discussed above, but as you have an auto there may be an alternative and far simpler cause. There is an interlock that prevents the engine from starting if Reverse is selected and the symptoms are exactly as you describe. Add a few years and a good few miles and unless the gear lever is pushed all the way forward, the system can think it is in Reverse and refuse to start. Next time it happens nudge the gear lever forward and see what happens.

Check the little spade connector on the bottom of the starter motor. It may well be on but it could be loose or dirty. That was the issue with mine with exactly the same symptoms.
Next time it happens, reach under and give it a wiggle. (Oo-err) if it starts, that's your problem.

Hi

Total immobilisation could also be the crankshaft sensor, took one out in 2 pieces last month so worth to check. Rest was working like you describe.

Good luck on tackling you’re ghost

I think it cranks but wont fire if immobiliser is still armed. So my 2p is bad earth on battery or starter wiring iffy somewhere . Check and clean all that up, make sure its tight. Free to check!

Little art said:

Hi

Total immobilisation could also be the crankshaft sensor, took one out in 2 pieces last month so worth to check. Rest was working like you describe.

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A bad crankshaft sensor will certainly prevent it starting, but it won't stop it cranking - which is the symptom here. I think it is either iffy electrics/starter or the Reverse interlock. Hopefully the OP will let us know how he gets on./starter

ronsealdeath said:

I think it cranks but wont fire if immobiliser is still armed. So my 2p is bad earth on battery or starter wiring iffy somewhere . Check and clean all that up, make sure its tight. Free to check!

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+1 @ronsealdeath. The other day we had a member on here whose problem was purely down to the sh1t battery connectors on the D2. You think they are tight but they ain't. Needs a socket of the right size and a hammer to hammer the connectors down onto the posts before doing up those blessedly stupid bolts

As long as the fob works to unlock it's not immobilised, immobilised means no crank but also solid red LED on the dash if the fob doesnt comunicate with the receiver... here it's some simple bad contact somewhere which lets the starter without feed or starter internal issue...if it was the solenoid then a loud clunck should occur when the plunger is engaged

Quick update. Problem not located yet but I've ruled out the immobiliser. Had a Nanocom plugged in to check and it wasn't immobilised when it failed to start. No fault codes logged either. Disabled the immobiliser anyway. There's a pattern emerging though. When the engine is cold it'll start no problem. After a longish run it won't start but when left for an hour or two will start again. Seems to be heat related.

Why have you discounted the starter?

When the starter solenoid is failing you can still hear it clicking when you turn the key. There is no noise whatsoever from the starter when the engine fails to start. It will start over and over again when cold first time every time.

DefenderPilot said:

Problem not located yet but I've ruled out the immobiliser.

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it was ruled out from the beginning based on the symptom as i explained

Interceptorxj said:

Why have you discounted the starter?

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Good point

DefenderPilot said:

When the starter solenoid is failing you can still hear it clicking when you turn the key. There is no noise whatsoever from the starter when the engine fails to start.

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So you ruled out the starter based on it's solenoid only? ... better dont cos it can have other internal issues too and the symptom is starter or circuit related.... believe me or not

If it is heat related, which it sounds like, then something must be expanding until the connection is no longer there. Dry joint in a circuit board somewhere? Have you tried wiring in the switch I mentioned? Could get you home when you do not wan to wait for it to cool down!

Bobdog said:

Check the little spade connector on the bottom of the starter motor. It may well be on but it could be loose or dirty. That was the issue with mine with exactly the same symptoms.
Next time it happens, reach under and give it a wiggle. (Oo-err) if it starts, that's your problem.

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What he said ^^^ especially given the heat related symptom, it's typically because the rocker cover gasket is leaking oil down the abck of the head where it drips directly onto the starter and runs round onto the lucar contact, get some switch cleaner on it & disconnect/reconnect a few times just to see... There will be no click because it's this connection that energises the solenoid.