Engine Cutting Out

[Flintstone]

The mystery began a few weeks ago. Cruising along on the A1 when the engine suddenly cut out. I managed to restart it but a mile or two further on it happened again. Coasted to a stop, RAC arrived and diagnosed a dead fuel pump relay which they replaced. On the way home the next day and about 100 miles later it happened again. After a few minutes in a lay-by the engine started and I pulled away only for it to die again in front of a brace of HGV's.

While waiting for the RAC I managed to start the car a couple of times and limp a few hundred yards, the fuel pump seemed to be the culprit with intermittent operation. Sure enough Offords found a bad connection to the pump relay which they repaired.

All was fine for half a dozen driving days during each of which I made several trips of 60 miles or so. A few days ago it cut out again. As the car had been idling for 20 minutes or so then driven in crawling traffic I thought it might be fuel vapourisation as the engine started after a few moments. It did this half a dozen times before quitting for good.

This time the RAC wanted to 'relay' me to Offords ie, swop the car from one flatbed to another rather than do the whole trip. It was late, I was tired and so I just asked them to drop it at a friend's garage near home. He bench tested the ignition module and it failed so this was replaced and a new coil thrown in for good measure.

I collected the car today. It had been left running for 20 minutes or so without any sign of a problem so I headed home. About 10 minutes later (clear roads) it quit and would not restart, the fuel pump was not running. Back at the garage the fuse was found to have blown. It was replaced and the pump ran, engine started.

Any ideas?

[mongoose]

I'd guess either the fuel pump is sticking(not uncommon),a slight tap usually frees it,but if i found this was definately the problem i'd replace it.Alternatively,you might have bad connections on the pump itself(also not uncommon).

[Flintstone]

Sorry, for got to say pump connections all cleaned up. Might be sticking I suppose, might that cause the fuse to blow?

Anybody know a part number for the fuel pump?

[mongoose]

Flintstone said:

Sorry, for got to say pump connections all cleaned up. Might be sticking I suppose, might that cause the fuse to blow?

Far more likely than corroded connections.When motors(pumps)start to drag or stick,they draw more amps than they should-it's where i'd be looking.

Disclaimer:-Of course it could be something completely different

[Flintstone]

OK.

Any idea where the pump comes from?

[GreenV8S]

Also check the condition of the wiring out by the pump, and the state of the inertia cut-off switch. I've had intermittant failures caused by both of these. The cut-off in particular is a right git because it causes current spikes that then cause problems in the rest of the circuit and causes repeated relay failures and damage to the relay socket.

[Flintstone]

GreenV8S said:

Also check the condition of the wiring out by the pump, and the state of the inertia cut-off switch. I've had intermittant failures caused by both of these. The cut-off in particular is a right git because it causes current spikes that then cause problems in the rest of the circuit and causes repeated relay failures and damage to the relay socket.

Oh, gawd. It just gets better and better

[griffter]

Flintstone said:

OK. Any idea where the pump comes from?

I've searched long and hard for the answer to this and not come up with anything conclusive. Various part nos are quoted - the best bet is to read the p/n off your existing pump. Some say the pump is the same as fitted to Lucas 14CUX injected Jag V12s. It is visually similar to that fitted to the Saab 900 turbo, again with 14CUX. There are other applications which use Bosch / Lucas pumps (the Lucas pump is a licensed Bosch design AFAIK) which look similar. Where the mystery starts is with flow rates, sustainable working pressures and current draw. Not forgetting the hose and electrical connections. Then you've got integral non-return valves or not...I would suggest:

1) replace like with like
2) try an aftermarket supplier like RPi for a suitable generic relacement
3) get yours rebuilt
4) risk a Jag V12 pump off ebay (usually £10 - £25)

[tvrbob]

Mine did this and it turned out to be a loose pin in the ECU multi-plug, easy to diagnose. I just eased the plug from side to side and the relay clicked in and out. Same principle applies to any 'open circuit’; just manipulate the wiring and connections to see if it affects the relay.

[Flintstone]

Update.

All pump connections etc were checked and checked again so I'm pretty sure it's not those.

Today I replaced the ignition module (amplifier) which failed a bench test and as a precaution the coil which I'm told are the same as those on a 1.3 Metro (Lucas DAB118 and DLB198).

Starter motor was looking very shabby indeed with lots of corrosion so what the hell, while I'm under there I may as well replace that and avoid being stranded somewhere wishing I had.

Fired up (eventually, after removing and drying the plugs) and it ran for about 15 minutes before suddenly stopping. The fuel pump could not be heard during several attempts to restart so that's the culprit I think, only failing when it's been running for a while.

While looking at it earlier in the day a friend remarked that it looked just like one he had at home, it came off a Mk III or IV Escort! Bosch 0580464008 and he's bringing it over tomorrow.

Stay tuned.

[david beer]

My imobiliser produced just the same effect, easy to bypass for "testing purposes". Email me for ways to do it.

[dlewis]

Paul

I take it this happens after extended periods of idling although originally on long runs.

You mentioned fuel vapourisation - a heat soak problem.

The pump may not need to prime if the pressure is up.

The fuse may have given out with high current when trying to turn over when hot. This may be evident from looking at the fuse blade.

Check the water temp through the idle period, then carefully feel the hose by the swirl tank and rad for different temps which, of course, there should not be.

Trust this helps.

[Flintstone]

Thanks for the suggestions. I'm really hoping it proves to be the pump as I only have time to replace that tomorrow then I'm away (working) for best part of the week. If it needs further troubleshooting I'll take up your ideas then.

[GreenV8S]

dlewis said:

The pump may not need to prime if the pressure is up.

Generally good advice, but on the specific point of the fuel pump priming this is done purely on a timer when you switch on and is nothing to do with the actual fuel rail pressure (which isn't measured in any way).

[Flintstone]

Ok, fitted the pump.

Car ran for about an hour before cutting out. Let it cool down, started and ran for 20 mins before stopping.

Let's have a look at the immobiliser shall we?

[tvr keith]

It's not the breather for the fuel tank blocked is it?
Run the engine for a bit and see if the tank is depressurised when you remove the filler cap.
If this is the case I wonder if the pump would eventually give up the struggle to pump fuel through and stop, causing the fuse to blow?
Keith

[Flintstone]

Forgot to mention I've checked the breather.

Pump starts after a while but not always immediately. The longer it's left the longer it is likely to start and the longer it runs which makes me think it might be immobiliser/heat related.

[Flintstone]

The Verdict.

It was the ECU. All repaired and up and running again courtesy of Offords.