Engine cut out whilst driving

[WarPig]

Was driving my 300TDI Defender along in 5th gear at 50mph yesterday when the engine suddenly cut out. I pressed the clutch to freewheel along and tried to start it again, it was turning over but wouldn't start. Had to pull over and come to a stop.

Tried starting the engine again but it was still the same, engine would turn over but wouldn't start. After 5 mins I was just about to ring recovery when I tried again and it started perfectly, and I drove home fine.

So, any ideas what it could be?

Earthing problem?

Faulty fuel pump solenoid?

[monkie]

It could be the solenoid with a dodgy connection as you suggest or air being drawn into the fuel system. All the cranking you did afterwards could have purged the air out. Check out the wiring as you suggest but also check the fuel lines and operation of the lift pump. A corroded pick up line from the tank is often a cause of air being drawn into the system when under load. It would only take a pin prick size hole to do it. 

[dailysleaze]

Possibly the immobiliser spider. Take a long piece of wire around with you so that you can connect the battery to the fuel solenoid if required. It will help you diagnose a bit also as it's hard to when it only does it when warm.

[WarPig]

2 hours ago, dailysleaze said:

Possibly the immobiliser spider. Take a long piece of wire around with you so that you can connect the battery to the fuel solenoid if required. It will help you diagnose a bit also as it's hard to when it only does it when warm.

So a wire from the battery +ve to the solenoid? Is that to listen for the plunger activating inside?

Edited April 27, 2019 by WarPig

[Yostumpy]

reply #2

[dailysleaze]

20 hours ago, WarPig said:

So a wire from the battery +ve to the solenoid? Is that to listen for the plunger activating inside?

To bypass the ignition system (or rule it out) so you can start the vehicle

[monkie]

When it happens again, leave the key in position 2 then disconnect and reconnect the fuel shut off solenoid. If you can't hear it click then try the above to see if you can hear the solenoid click open. If that doesn't resolve the none starting issue then before you crank the engine over see if the fuel filter contains air by opening the vent screw on the fuel filter head. If it is filled with air, pump fuel into the filter using the lift pump lever. I don't think there is a vent on the injection pump on a tdi if memory serves me right. Then try and start it. I imagine it will be one or the other that will get you running again. 

Edited April 28, 2019 by monkie
Clarity

[Tanuki]

Could also be worth - when it cuts out, try removing the fuel-filler cap.

If you get a noticeable sucking sound, you could have a blocked tank-breather and the buildup of vacuum as fuel is drawn from the tank is temporarily defeating the sucking-power of your lift-pump until some air leaks-in to relieve the vacuum?

[WarPig]

2 hours ago, Tanuki said:

Could also be worth - when it cuts out, try removing the fuel-filler cap.

If you get a noticeable sucking sound, you could have a blocked tank-breather and the buildup of vacuum as fuel is drawn from the tank is temporarily defeating the sucking-power of your lift-pump until some air leaks-in to relieve the vacuum?
 

I do often get that sound when the tank is empty and I remove the filler cap to add fuel.

[Davew2]

Same thing happened to us today pulling our caravan( increased load)

Did you ever get to the cause?

[Snagger]

5 hours ago, Davew2 said:

Same thing happened to us today pulling our caravan( increased load)

Did you ever get to the cause?

Sudden cut outs would be a problem with the solenoid or its power supply. A fuel starvation or air ingress issue would likely see some surging and rough running before it cut out.  
 

Check the solenoid and its feed wire for cleanliness and condition, give the space terminal a light squeeze with pliers to tighten its grip when refitted, and add a little grease to the connection to keep dirt and water out.  If you continue to get sudden cuts, check the rest of the wiring, especially on the back of the ignition switch, for security and cleanliness of contacts.  It could be a failing ignitions switch or solenoid, though.  Running a bypass from a live feed directly to the solenoid would allow you to identify which is failing, and you can stall the engine in 4th gear to shut it off.

[cackshifter]

I had the same thing, it was a dodgy ignition switch. It is just possible to change it without removing the column lock but as above, you need to do the diagnostics

[Snagger]

* spade terminal, not “space”.

[Litch]

I had this on my 300TDi about 4-years ago and it was down to doggy fuel.

Had filled up at a Tesco filling station in Stoke On Trent and on the way home to Bedfordshire the engine cut out stone dead on several occasions (no spluttering, it was like I had flicked a switch) however each time it re-started after I had pulled over or even before I had coasted to a halt.

This un-nerved me and next day I set about checking all connections but found nothing. I filled up a few days later and over the course of the next week it did it again but only a couple of times. Before heading up the motorway again I refilled (second fill-up since SOT Tesco) and it only did it once on that journey but after another fill up it never did it again. 

All I know is that I never used that Tesco filling station again (it was a pain to get in & out of anyway).