Stalled - and won't restart

[Johnners733]

Hi there,

My 56 Avant has made an undignified trip home on the back of a transporter after it coughed it's last at some traffic lights - and then wouldn't restart. Still won't.

It had made a journey of less than half a mile, and I had noticed that the revs were quite high (as though when first started). After I'd rolled it back out of harms way I tried to get it going again. For a period, the starter would run and run and run (without success) upon touching the start button, and then had to be stopped by turning the key to the 'off' position. Now, it will still turn, but only if the finger is on the starter. No other erroneous signs (eg no warning lights on dash). No obvious fuses out (although was unable to check any in the so-called Ebox as I could not find it, and manual was safely at home in the house). (D'oh).

Any obvious things for me to check before I give the dealer a ring and get him to come and take it away (or alternatively, anyone know a mobile specialist on the Harrogate side of York...?!).

I feel sure it must be something simple (it was a bit like the 'engine flooded' from days of yore) but the AA man who came remarked that the engine seemed to be turning over pretty fast (although no faster than I remember...but he's got me worried now)...

Any help or suggestions gratefully received for this new owner who hasn't even got round to posting pics yet

Many thanks

John

PS tried a search during the two hours I was at the roadside and couldn't find any posts that described what I was experiencing. Apols if that's not the case.

[RS6BRIT]

That is a tough one. I'd have expected an EML of some sort. First off get yourself a VCDS set up and check for any codes (some don't light up the EML.

If I had to stab in the dark I'd say possibly the throttle. If it's stuck shut then that might explain the failure to start, and if it's sticky it could explain the high revs when you started it.

[Johnners733]

Thanks

Having read about a bit I was wondering whether an iffy clutch switch could be to blame? If it won't 'recognise' that the clutch is depressed (like it's owner...) then I guess it wouldn't start; some other threads have identified that iffy clutch switch then gives the symptom of having to hold the starter button down (rather than press and release).

Grateful for any further views

[R1RS4]

Thanks

Having read about a bit I was wondering whether an iffy clutch switch could be to blame? If it won't 'recognise' that the clutch is depressed (like it's owner...) then I guess it wouldn't start; some other threads have identified that iffy clutch switch then gives the symptom of having to hold the starter button down (rather than press and release).

Grateful for any further views

Yes I would say clutch switches, one makes (contact) when depressing the clutch and the other breaks (contact) works as a fail safe

Normally, with the ignition off, dip clutch and select gear then back to neutral, dip the clutch several times, whilst doing this switch air con, auto lights, radio etc to save power then have another go

Yes better if you have Vcd's, but if you don't then try the above then investigate further when you get home

[RS6BRIT]

It could be the clutch switch, however even with a knackered clutch switch the car should still start. The upper switch is for cruise, the lower is for starting and general driving iirc. I recently knackered a clutch switch by not fitting it correctly (a very common mistake, just ask Mike !!) And even though I had to hold the starter it still started. I've not heard of a clutch switch stopping the car from starting altogether.

[Johnners733]

Thanks again all. We shall see...the car is in the hands of the professionals at JCT600 in York. I will advise the outcome.

Funny how things turn out. I'm working from home today - loads on, phone won't stop, the usual. Needed to head into town for a meeting this am so thought I'd give JCT a ring to see if they could help get the car the four miles from home to dealer. No dice - they don't do recovery and they couldn't send anyone to look at it here (worth a try I thought!). They did recommend someone locally though. Timed out, had to go to meeting. Got home, rang the recommended guy, he was coming back from a job, said 'I'll come straight to you'. So having all but given up on getting it to the dealer today (and knowing I'd be in London the next two), the call was made, the car collected, deposited at JCT and booked in by service receptionist who said 'I've got your car here' in under 30 minutes. Cost me £50 to shift it.

Let's hope the diagnosis and cure is as swift, simple and inexpensive. (OK, so it could happen...).

John

[RS6BRIT]

Fingers crossed for you buddy. Let us know what happens.....

[R1RS4]

The way I read the circuit I found was that unless 1 set of contacts break and another set makes the car won't start?

Sounds logical to me, or why have the switches there?

[RS6BRIT]

they are there for different purposes. The upper one lets the car know the clutch is fully engaged and is mainly used for the cruise. Its the upper one that turns the cruise off if you touch the clutch pedal when using cruise control.
The lower one lets the car know that the clutch is all the way down and as such it allows it to start at the touch of the button. It does use the upper one during start up I assume, as when the bottom switch is busted you can still start but you have to hold the button down, but you do still have to have the clutch pressed so the upper one must factor in.
I am happy to be corrected, and I do hope for his sake that its as simple as a clutch switch.

[R1RS4]

they are there for different purposes. The upper one lets the car know the clutch is fully engaged and is mainly used for the cruise. Its the upper one that turns the cruise off if you touch the clutch pedal when using cruise control.
The lower one lets the car know that the clutch is all the way down and as such it allows it to start at the touch of the button. It does use the upper one during start up I assume, as when the bottom switch is busted you can still start but you have to hold the button down, but you do still have to have the clutch pressed so the upper one must factor in.
I am happy to be corrected, and I do hope for his sake that its as simple as a clutch switch.

+1 sounds about right mate

[JCviggen]

It's not going to be a clutch switch issue as OP has indicated the starter turns the engine over but it doesn't start. Could be a couple of things really from a vital sensor (like cam position) to a fuel pump relay or something. The answer is most likely in the error codes.

[PetrolDave]

The answer is most likely in the error codes.

+1

Trying to diagnose this fault, like many others, without knowing the fault codes is basically bluffing in the dark - which is why VCDS is such a useful tool and even though it's expensive usually ends up paying for itself in saved garage bills or unnecessarily changed parts.

[audi_do_dat_den]

My money would be on the crank position sensor failing.
Not a monumentally expensive part, but a bit of a pig to get to i think....
Good luck mate, ill be watching this post and hoping its a quick fix for you.

[Johnners733]

Thanks all,

No conclusive news but audi_do_dat_den would appear to be closest...from a fragmented phone call earlier (train home) to JCT it's throwing two fault codes - one cat related, the other (I think) was crank position sensor. Hoping 'a bit of a pig to get to' is a relative term...they will be in touch with more detail tomorrow...

[R1RS4]

Dave, He does not have Vcd's, so it was suggestions that might get him up and running in the interim