audi a4 b8 2008 2.0 TDI Help ! intermittent random not starting - ignition switch or starter?

[mikie]

Hi

I have recently had problems with my car not starting randomly, It's got high miles - 193,000, recently had the crank position sensor replaced on it as car wouldn't start at all.

I have had the RAC run their diags on it and no faults found.

Sometimes and randomly the engine cranks but won't start, tried keyfob in different positions, and spare keyfob, this is not a cold/hot issue either, and no errors on dash.

A mechanic said to me next time this happens to check if the steering wheel is locked, to confirm no issues with the steering lock.

Having searched the internet high and low and I don't seem to be the only one who has had this "random intermittent" problem but this was ages ago and no updates : -

Question A4 B8 2.0TDI 143 Starting Problems (http://www.vwaudiforum.co.uk/forum/showthread.php/117993-A4-B8-2-0TDI-143-Starting-Problems)

Please can someone confirm exactly what this part does : - audi part number 8K0909131C - this is the ignition switch part where the key "sits and is docked"

Does it send a "signal" down to immobiliser to disable the immobiliser or not? - to confirm my key has never got jammed in the ignition switch,

Or could this simply be the starter motor ? - audi part number - 03L911021 - is there a way to test a starter motor? or does it simply work or not?

Or something to do with a clutch pedal sensor (had this as a problem on my old Passat) ????????

Many thanks in advance.

[mikie]

Anyone ??

Been to Audi today.. they said although my ignition switch is not smooth inserting the fob is working as if and when fault happens the engine is cranking but not starting..

They also ruled out starter motor as a.starter motor either works or doesn't apparantly.

Is there a clutch pedal sensor or audi said maybe fuel injectors ??

Any thoughts opinions ?

[mikie]

Hi

Car wouldn't start today, RAC came out, used Easy Start, car started.

Error code P008700 Fuel Rail Pressure - Too Low

Have stopped and restarted the car and it's fine now.

So .. I suspect it could be fuel filter or fuel pump next to fuel filter.

However... if the car is working and this is an intermittent problem and I can get fuel to the fuel lines in the engine bay on the left hand side before the high pressure centre on the right hand side could this be something a sensor somewhere?

Thanks

[Gunnark100]

Sorry, but there is no easy magic answer for this random issue...all you have is this error code, so you must go by that, starting from cheapest...
16471/P0087/000135 - Ross-Tech Wiki (http://wiki.ross-tech.com/wiki/index.php/16471/P0087/000135)

[mikie]

Hi Gunnark

Thanks for your reply.

I managed to get further information with further diagnostics but now down to one of three parts and will update.

1.) could be fuel filter
2.) could be fuel rail high pressure sensor :-

AUDI 2.0 A3 A5 A6 Q5 QUATTRO FUEL RAIL HIGH PRESSURE SENSOR 55PP26-02 03L906051 | eBay (https://www.ebay.co.uk/itm/AUDI-2-0-A3-A5-A6-Q5-QUATTRO-FUEL-RAIL-HIGH-PRESSURE-SENSOR-55PP26-02-03L906051-/252523948883)

or could be the fuel pump next to fuel filter (low pressure one) as the fuel pump in the tank is fine

Audi A4 2008 - 2016 B8 2.0 TDI Diesel Fuel Pump 8K0 906 095 B | eBay (https://www.ebay.co.uk/itm/Audi-A4-2008-2016-B8-2-0-TDI-Diesel-Fuel-Pump-8K0-906-095-B/132410186044?hash=item1ed443193c:g:TOYAAOSwmphaF-8R)

More fun ahead..