Hi All,

My 1992 230E (automatic) randomly cuts out. One minute driving normally, the next it just suddenly stops. No spluttering or anything. On occasion it starts running again before I get to stop.

Other points which may help:
1 - EZL (I think that's what it's called) was replaced last year
2 - It seems to be a fuel supply related issue as when I put the ignition on afterwards, normally I cannot hear the fuel pump prime. After a couple tries it sometimes pumps again and then it starts
3 - Other times I tap the fuel pump relay a few times and then the fuel pump runs and it starts, but this may be coincidence
4 - It had an immobiliser installed which has been bypassed. However, there's an earth wire linked to the immobiliser box which if disconnected the car won't start. So it still seems to be partly wired in and may have an effect? Maybe they just shorted the switch which deactivates it? I can hear a clicking from the immobiliser box under the steering wheel from time to time.
5 - Auxillary fan has been acting erratically. It sometimes switches on as soon as I put the ignition on or it comes on when the car is clearly not hot yet. It sometimes switches on and off in close succession like someone was flicking a switch on and off. I was thinking this is a loose connection and that if there's no signal it runs by default as a precaution?

How do I go about diagnosing this? It's not safe having my car cut out at 120km/h (75mph) in the fast lane on a freeway...

Thanks,
Jason