Totally Lost!

[Guest Radders]

Woke up the other morning battery as flat as a pancake. Jump started it did a few checks and concluded a naff alternator. Fitted brand new one today and a brand new battery. The car starts and runs perfectly but when I turn the ignition off (and remove the key) the engine continues to run. The only way to stop it is pulling the alternator plug. It is definitely not the alternator or battery and I've bypassed the ignition switch and barrel so it definitely isn't that either??? Any ideas...I'm stuck, well and truly :-(

[Guest Radders]

Just to add...the ignition light stays on when you turn ignition off and remove key.

[Pintogogo]

Same thing happened with my Nissan primera. turned out starter motor was shagged n engaged all time flattening battery whilst driving and when swithched off would continue to turn engine until battery completely flat, recon starter solved problem, hope this helps

[Guest Radders]

Starter motor is working as it should. Thanks for the info though.

[Guest 2b cruising]

Sound to me like your new alternator is faulty, sending power to the ignition.

A diode could do this.

If you shop bought it, I don't think they would be against you having another as a trial and report your findings to them.

I think the only other thing it could be would be your ignition switch.

However, if this was good before, why would it suddenly fail just because you changed the alternator and battery.

I am thinking more and more a faulty alty

[Guest Radders]

I have a voltage test meter.....the new alternator and battery test fine?

[Longboarder]

First have you done any other work on the car, particularly electrics but anything else in the weeks before this fault started?

Presumably the car is sitting there right now with the ignition light on unless you have pulled off one of the battery terminals.

First step I would take is to remove the fan belt and the alternator plug. (Alternators don't like turning without the plug in so brief tests with the engine running for a few seconds will not overheat the engine or blow the alternator as it isn't turning). Ignition key is in your pocket and Reconnect the battery that you have charged up overnight. The ignition light should be off. If its on then you have a short in the wiring that goes from the ignition light to the small terminal in the alternator plug (61 or L). And it's not the alternator itself which is not connected. Now earth the small contact in the alternator plug with a bit of wire. (Note well. Do not earth the big contacts (51 or B, B+) Your car may catch fire). Ignition light should not come on until you put the key in the ign switch and turn it on. Note you haven't started the engine yet.

If the ign light does come on with ignition off and small terminal earthed then you have a back feed from a circuit not controlled by the ignition key. You can try going through the fuse box. Record what rating fuse is in which position, then remove them one at a time but not replace them yet. If the ignition light is still on then pull out all the relays one by one. You are looking for the step that finally puts the light out. The circuit that puts the light out will be the circuit that is backfeeding the ignition circuit. That's enough for starters and should give a good indication of where the fault lies.

 

Nigel

[Guest Radders]

Thanks Nigel...sounds like a plan. I'm going through it some more tomorrow with the father in law ( mechanic of 40yrs) so I'll show him your advice. Cheers.

[Guest Radders]

Bish and bosh, problem solved....turns out a wire on the starter motor had been wired wrong and had worked loose...this then touched another wire and gave a permanent live feed to the ignition. So glad that is resolved!

[Guest 2b cruising]

Well done Radders. Hope you've been out in this lovely weather.

I've been to Hastings, Estbourne and Brighton. Terrific weather.

Car running great.

[Guest Radders]

Cheers!Yes...I've been blasting around all day! Fabulous day and weather...4 people were taking pics of my car today...and that's just the ones I clocked. She gets so much attention it's unreal.

[Guest snowy2]

it would have been the same in Dolly.... ;-)

[Guest Radders]

Yes Dave...it was :-)