Possessed Car! Turned ignition off but engine still running

prettypennies

Not sure where to put this one but can anyone explain this to me?

I turned the iginition off in my car (peugeot 406) and took the keys out but the engine kept on running!!! Stopped eventually - struggled a bit to start and then didn't want to turn off again.

I assume it is some kind of electrical fault. Would be grateful if anyone would shed some light on what may have gone wrong.

Nile

Hello prettypennies


I've moved your thread to the 'Motoring & Public Transport' board, where it should get more views and responses.

MOVING THREADS FOR BETTER RESPONSES

Martin’s asked me to post this in these circumstances: I’ve asked Board Guides to move threads if they’ll receive a better response elsewhere(please see this rule) so this post/thread has been moved to another board, where it should get more replies. If you have any questions about this policy please email [email="abuse@moneysavingexpert.com"]abuse@moneysavingexpert.com[/email].

Kind Regards

Nile

vansboy

https://www.honestjohn.co.uk clik TechnicalMatters.

But DO get it sorted FAST!!!

Do you know how to stall it safely??

If it's diesel, this will be a bit harder, but practice, with the handbrake on firmly & use 5th gear gently on the clutch - with NOTHING IN FRONT !!!

VB

tomstickland

What sort of engine is it? Petrol or Diesel? Fuel injected?

I had a similar problem when I had an earth fault on one of my cars. Basically, when you turn the key off that should stop voltage from reaching the engine ECU / coil. With my earth fault then another device was not earthing properly and so it ended up putting positive voltage onto the ECU.

So, yes, probably an easy to fix electrical fault.

One problem though, your average garage is no use at fault finding electrical things like this.

cc25

Is the engine diesel? There is small electrically operated valve near the fuel pump, which will close when the electrical supply to it is switched off. This, in turn, cuts off the fuel supply to the pump, and the engine stops. If the valve is worn, it will not shut, and the engine keeps running even when you have removed the key! A relatively common problem on some older diesel cars.

It is easy to test the valve, and replace it if worn. At a guess, the valve will be around £30 from a motor factor (not a main dealer), and will take around 30 mins to fit.

prettypennies

It is a 1.8 diesel engine on a P reg. Thanks for the advice.
Also, don't know if this is related but before it started doing this, when the engine was is neutral it the revs would keep going up and down.
Have only had the car a few weeks a so don't know much about its history.
Thankfully haven't got shot of my trusty old Astra yet. So I can run that until its's sorted. Dad offered to have a look at it for me. He suggested the valve thing. Any pointers I can give him re locating and fixing it?

paulie558

Had exactly the same on a 406 which had over 200k on the clock(diesel) engine used to make a rattly noise when it kept running,but found turning ignition back on and leaving it 10 secs or so meant it turned off ok.It was like this for about 2 years!

rdwarr

I had this once. It was just a bit of loose metal in the fuse box. Good luck!

dazza001

Assuming that your car is petrol,

This could be caused by defective or incorrect spark plugs(there are different types - Hotter or colder plug types) if the plug is defective or the wrong type, it gets hot spots and can still ignite the remains of petrol vapours in the combustion chamber even when the power to it has been switched off. This would be the first thing to check and the easiest to put right(check in the manual for correct type).

There may also be an electrical connection somewhere on the carburetor that connects to a fuel cut off solenoid - check the condition of this for corrosion/bad contact etc. (be careful around this area though - you dont want any sparks if fuel is present.)

This is more common on older cars that have carburetors instead of fuel injection as the fuel is drawn in because of the vacuum created when the piston moves down so it keeps on putting fuel in and your hot plug continues to ignite it and so on and so on until the plug cools.


There can be many causes of this but the main ones that I have seen are the ones mentioned above, other causes that I know of though can be:-

Faulty Carburetor (leaking or sticking float chamber, sticking cables/return springs/levers)
other types of carburetor fault jet or needle problems.
(Check the general condition of the carburetor - is there any evidence of fuel Leakage?)
Incorrect ignition timing, check distributor operation (are all vacuum pipes connected?)
Badly coked engine( not so common these days with modern fuels and oils -but its a small possibility )

In my experience if your car is Electronically controlled (ie, fuel injection, mapped ignition etc) then there is not much that you can do yourself as a DIY mechanic because Diagnostic computers are required to read the ECU to diagnose the fault (they calculate when the plug is firing against fuel injected and position of piston etc, to make the diagnosis).

I have had a few cars that have done this and it is not a major problem, I suggest that if it is an old car like mine(J reg Cavalier), then providing there are no petrol leakages then it may not be worth doing anything about it, as it is not dangerous (providing you keep it in neutral with your foot on the brake until it stops) and could cost a fortune to put right if you let a garage get their hands on it.

(Ps, I have had a few people ask me this so I will answer before it gets asked - It will not start up again on its own if you have removed the ignition key as the plug will have cooled)

Hope this helps

dazza001

That will teach me to read all the threads before replying, anyway hope that previous post will help someone in the future with the same problem with a petrol engine

Anyway, It sounds like your diesel pump needs recalibrating, especially because you said it is idling eratically, that would cause an incorrect fuel delivery at the time of shut off, this is not something that can be done yourself though unfortunatley, it is very specialist.
I would still check all the connections around the diesel pump, Engine management system etc, as it could be something simple like that, eliminate all possibilities before taking it to a garage however small they seem, it really can be something so small like a bit of corrosion on an earth tab.

Also a final note, take it to a diesel specialist repair centre rather than an all round/fix every car type garage as they will not specialise they will just have general equipment.

Or you could still just save even more money and leave it, as with a petrol engine it is not really a big problem and not dangerous, unless it is really bugging you.


Cheers

BobToo

You need a fuel stop solenoid, this costs about £30 from Euro Car Parts but you should get one from a local factor. It's dead easy to change- if you, or anybody you know, are remotely handy it's a 5 min job. You'll probably need to know if your pump is Lucas (Rotodiesel and CAV are the same as Lucas) or Bosch. It should say somewhere on the pump.

Erratic running is often caused by an air leak in the fuel line. The most likely culprit is the hand pump that's used to prime the system after a filter change. This is located on the fuel filter and costs about £35 from a motor factor. These pumps can deteriorate to the point where the car won't go so don't put off replacing it. Again you'll need to know what kind of fuel system you have (same as the pump). If you ask the motor factor for a filter head they should know what you're after.