4.6 THOR cutting out

Afternoon all,

I'd just filled up yesterday, got 2 mins out of the fuel station and it immediately cut out. Swapped one of the engine relays RL19 with a fan relay and up she fired as if nothing had happened. 5 mins later cut out again. Swapped the other engine relay RL2 and again fired up, then died 5 mines later. Had a play about with my new nanocom entering the eka code. Up she fired.. for 5 mins. Tried resyncing the key (in the door holding down the buttons) and again got 5 mins out of her.

When she cuts out she will crank fine but no spark. I did have a code P1231
Fuel pump relay short circuit to battery
supply - not the fuel pump itself

But it's been running again and I'm certain i've heard the pump running for 2 seconds before start. This all feels very immobiliser like? but I'm struggling with what to do next. Thanks for reading.

DeRangie

DeRangie said:

Afternoon all,

I'd just filled up yesterday, got 2 mins out of the fuel station and it immediately cut out. Swapped one of the engine relays RL19 with a fan relay and up she fired as if nothing had happened. 5 mins later cut out again. Swapped the other engine relay RL2 and again fired up, then died 5 mines later. Had a play about with my new nanocom entering the eka code. Up she fired.. for 5 mins. Tried resyncing the key (in the door holding down the buttons) and again got 5 mins out of her.

When she cuts out she will crank fine but no spark. I did have a code P1231
Fuel pump relay short circuit to battery
supply - not the fuel pump itself

But it's been running again and I'm certain i've heard the pump running for 2 seconds before start. This all feels very immobiliser like? but I'm struggling with what to do next. Thanks for reading.

DeRangie

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That sounds like a possible fuse box problem to me, quite common. Resyncing the key most likely did nothing, just allowed cool down time.
You can turn off EKA and the immobiliser in the BECM with Nanocom to rule them out as a problem.

Datatek said:

That sounds like a possible fuse box problem to me, quite common. Resyncing the key most likely did nothing, just allowed cool down time.
You can turn off EKA and the immobiliser in the BECM with Nanocom to rule them out as a problem.

Click to expand...

Well I did try resyncing the key again and it didn't work which left me a bit baffled. All my searching thus far has thrown up fusebox like you said, crankshaft position sensor or horrible wiring/ECU/BECM issues. However the way it starts stationary and cuts out without moving makes me think it's not loose/dodgy wiring?

DeRangie said:

Well I did try resyncing the key again and it didn't work which left me a bit baffled. All my searching thus far has thrown up fusebox like you said, crankshaft position sensor or horrible wiring/ECU/BECM issues. However the way it starts stationary and cuts out without moving makes me think it's not loose/dodgy wiring?

Click to expand...

Corrosion and bad connections in the fuse box are common, lift the lid and see if there are burning smells. CPS failure is also common but the fault logged makes it look more like the fuse box.

Datatek said:

That sounds like a possible fuse box problem to me, quite common. Resyncing the key most likely did nothing, just allowed cool down time.
You can turn off EKA and the immobiliser in the BECM with Nanocom to rule them out as a problem.

Click to expand...

+1

I had a cracked solder connection underneath the fuse board which have cutting out problems, also affected the headlights which you may not notice in the daytime.
The board looked fine and no burn smells otherwise.
Culprit was one of the posts underneath that has a brown wire to it. If i recall it was the middle one

kermit_rr said:

I had a cracked solder connection underneath the fuse board which have cutting out problems, also affected the headlights which you may not notice in the daytime.
The board looked fine and no burn smells otherwise.
Culprit was one of the posts underneath that has a brown wire to it. If i recall it was the middle one

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Dry solder joints are also common on the connector blades.

I think you may find it is dying crank posItion sensor. The symptoms you describe are absolutely spot on.

As the die, they start to break down when hot. As soon as they cool, they work perfectly, until they heat up again.

A dead CPS will allow the engine to crank but no spark. It typically won’t throw a code, as if it is dead, the ECU doesn’t know the engine is revolving.

+1^ if you can take a resistance reading possibly from the cps when cold, then run the car until it's cuts out and take reading again.
If it's possible that is, although a scope would help.
Battery box à good culprit as stated. False side light warnings when bulbs aren't blown denotes solder joints..

Hi everyone. Thank you for all your help. After some more googling of my symptoms I went with a crankshaft position sensor and that has cured it (touches all available wood). For my own knowledge Mark Piercy how would I take the reading? (not hugely electronically inclined).

Cheers,

DeRangie

I had EXACTLY this fault on my AUDI A8 a couple of years ago. Would cut out without warning and certainly without a fathomable pattern, on one occasion in the middle of an extremely busy road junction. Got a BOSCH CPS off eBay and that immediately resolved the problem.

Fuse box needs stripping down n fixing

DeRangie said:

Hi everyone. Thank you for all your help. After some more googling of my symptoms I went with a crankshaft position sensor and that has cured it (touches all available wood). For my own knowledge Mark Piercy how would I take the reading? (not hugely electronically inclined).

Cheers,

DeRangie

Click to expand...

By unplugging the cps but not removing it. You can use a dvm set to ohms and check it's resistance when hot and cold.