Engine Cutting Out

[BrianMillar]

Went out for a trip round the countryside today and the car cut out on me twice in the space of about 5 miles.

First time restarted almost immediately.
Second time would not start engine turning and trying to fire but no fuel pump.
I quickly swapped over the two silver relays and it started first turn.
Got me home via my local garage (to order two new relays) without further problems.

I thought I had cured the cutting out problem in the summer but it seems to have reappeared.

Now a few questions that I hope someone can help with:

1. Why do these relays get so hot? Are they rated correctly for the job they are doing? They are 30A relays
2. Can they be replaced with uprated relays? (say 40A as I know these are available)
3. The bible mentions something about the fuel pump relay being ‘electronic’ (Page 244) rather than standard and the electronic relay switches the fuel pump off automatically. This does not make much sense to me. Why shouldn’t a standard relay be fitted and why would it not work correctly?
4. What sort of current should a healthy fuel pump be drawing?

Once I get the new relays, I intend to dismantle one of the old ones to see if there is anything obvious going wrong such as burnt contacts.

[spend]

Check the resistance of the power & grounds of the relays, you may have bad contacts - always well worth using contact grease on these parts, it is as beneficial as copper slip IMHO.

Dave

[BrianMillar]

The relay spade contacts are clean and smeared with silicone grease. I did that in the summer when I last had the problem.
I will check out the earthing tomorrow. But that does not explain why just swapping the relays over cured the problem. If it's a bad earth then changing the relays should not make a difference.