Strange intermittent starting issue 2006 S-TYPE R

[The Voices]

I am experiencing an unusual problem with my 2006 S-TYPE R. and hoping for some input or suggestions.

It has recently started having issues starting from cold.

I will try to provide as much info as possible, apologies for the long post:

 

When turning the key, sometimes nothing happens, sometimes there is a mechanical 'clunk', sometimes it tries to turn over and occasionally, it starts.

Repeated attempts eventually get it to start, when it eventually does, it just starts as normal as soon as I turn the key, rather than turning over for ages.

Sometimes after it starts, it seems to run 'lumpy' for a while, other times it is as smooth as usual.

 

Battery is brand new and charged, I replaced the battery negative cable as a precaution, as the terminal clamp had 'cracked' (the fault was there prior to replacing the cable, doesn't seem to have made things better or worse)

The flap on the ignition barrel isn't sticking open, when I insert the key, the seat and steering wheel move to the memorised position.

The dashboard lights come on when I turn the key to the appropriate position. 

 

Reading the fault codes after trying to start it reveal P0340 and P0345, which are camshaft position sensors for bank 1 and bank 2 (or wiring ?)

It has been suggested that it is very unlikely that both sensors have failed at the same time, more likely to be a common issue affecting both banks (possibly poor earth / grounding ?)

Once it has warmed up, it will repeatedly start on the first turn of the key.

 

A friend suggested connect a jump lead from a metal point on the engine to a good earth, to see if the engine earth strap was loose.

Thought that this had identified the issue when I tried it yesterday, as it subsequently started at least six times in a row (removed the key, locked the car, unlocked it, key in ignition, started first time)

It appears as though this wasn't the case, was only starting because I had already had it running, so must have warmed up enough.

 

Left it overnight, tried to start this morning and it didn't even try to turn over, immediately tried the jump lead trick but still wouldn't start (unless of course I wasn't getting a good connection at one end ?)

I think that at one point I have also seen a 'coolant temperature sensor' fault code, but it seems to warm up as normal, doesn't overheat or loose water.

 

So, poor earth, sticking starter motor or relay, faulty coolant sensor, ley lines, car parked on ancient native American burial ground, or none of the above ?

[The Voices]

Just tried swapping over the starter motor relay in the fusebox under the bonnet (R20 if the online diagrams for a 2006 model are correct)

 

Exchanged it for the identical relay for the headlamp power wash (using the theory that this relay will not have performed as many switching operations)

 

Still took 5 attempts to start.

 

As an experiment, switched off immediately, removed the key, locked the car and it restarted first turn, repeated this a few times.

 

This suggests that my theory that the issue might be temperature related is incorrect (only previously tried restarts when the car has warmed up)

[Big John]

Hi Jon

If turning the key results in nothing, a click or a start that sounds like the problem is the starter. I assume that you are not getting the engine to even turn over when it "fails to start". If the starter is actually turning the engine over at normal speed (every time you attempt to start) then you can rule it out as the problem. If not that is where I'd start. I would try to check the voltage reaching the starter when you turn the key either with a voltmeter or a test Bulb.

Regards

John

[The Voices]

Thank you, I am beginning to suspect the starter motor might be the culprit.

 

I found the 'engine earth strap', unfortunately not quite what I was expecting.

It seems to be just a single wire that appears out of the rest of the loom, only around four inches of cable with an eyelet on the end, bolted to the front of drivers side cylinder head.

Pain in the neck to get to it properly but using my inspection camera and following the wire to the bolt, everything feels okay, no exposed wire that I can see, bolt seems tight.

 

I would like to inspect the + and - cables going to the starter motor as well, but can't get the car high enough in the air by the roadside to remove the undertray. Looks like taking it in to work and putting it on a ramp might be the best option.

No idea where the starter motor even is !

Presumably where the gearbox meets the block ?

Did wonder whether the starter motor could be sticking or not engaging properly (solenoid issues ?)

If it's the same age and mileage as the car, (2006 and 176,000 miles !), it might be due for a replacement ?

[Big John]

Hi Jon

http://www.jagrepair.com/images/AutoRepairPhotos/CarPDFFiles/SType/S-Type 2002.5-2008-FSM-Workshop.pdf

You will find lots of useful stuff on the jagrepair.com site.

Good Luck

[The Voices]

Thank you !