Intermittent Engine Fail.

[BobBate]

Hi Sam,
Inertia switches are either on or off if they are working correctly but when defective they can be in a partially closed state that sometimes breaks the circuit and causes the engine to cut out. Once current is removed from the circuit they may then permit current to flow again so that the engine restarts. As the test to eliminate this possible fault is so easy as described it seems a shame to overlook it. If the switch is ok it's one possibility out of the way and we can move on to another test.
Bob

[BobBate]

Hi Sam,
The inertia switch is fitted to the A post on the left hand side of the passenger's floor well just above the fresh air pull lever. Be nice if this is the problem, in not, please come back.
Bob Bate

[Flappers]

Sadly no, I disconnected it and connected the wires and still it dies and jumps in again. The switch isn't where you thought, its right next to the door pillar on this. Anyways, 1 down

[Flappers]

I've received the relay replacement today and tested.... But problem still exists. So its not the relay or the inertia switch. I think it must be a fuel issue?

[BobBate]

Hi Sam,

The A Post is where you found the inertia switch. Perhaps my description wasn't so good. Let’s do some more checks. It would be beneficial to confirm without doubt if the fault is due to fuel pump electrical supply failure. May I suggest?

Check that ignition is off.
Remove the spare wheel cover and pump shield at the rear of the boot and hopefully locate the fuel pump.
Check that the cables are securely attached to the pump.
Identify the earth cable that is attached to the pump negative terminal and check that it is firmly attached to the earth point which I think is close to the pump. Don’t have one of these cars in the workshop so writing from memory.
Check that the earth point is clean. Water ingress often causes corrosion at this point and a high resistance connection which can cut off the pump.
If any of these cables are suspect, rectify the problem and road test the car. Such faults are uncommon but we have seen them over the years and these points are easy to check. There’s little value spending hours testing complex fuelling and ignition components to find that there is a loose cable on the pump.

If all pump cables are good we can move onto the next test which ideally involves the use of a test meter having a scale that will measure 12 volts DC. Without this we can still move forward but it would help me to know which direction to take.

Bye for now
Bob

[BobBate]

Hi Sam,
Diagnosis from this point on will be quite complex so it's probably better if we continue by 'phone. Will call the mobile.
Bob

[Flappers]

We finally found the issue, it was the high resistance connection on the Fueling ECU located with oscilloscope testing. A huge thank you to Mr Bob Bate whom generously lent his time and huge knowledge to the problem. Purring like a kitten, thanks again all that helped