Fuel starvation + electrical weirdness

[moomin]

On a 1984 Coupe GT5E (JS Engine)

Recently I replaced my fuel pump and relay as the relay had died, has been fine for three weeks until yesterday it developed a fuel starvation misfire.

80% of the time
Start car
Relays click
Fuel pump turns on
Car starts
Drive off it starts to misfire
Then clears up
Then comes back
repeat until stopped

10% of the time
Fuel pump won't fire at all
Bash the pump or bash the relays makes no difference
then randomly it'll work

rest of the time its perfect

Problem can't be forced to happen under; load, accerlation, deaccerlation, heavy cornering, driving over bumps or any other abuse.

Seems to be random

HELP!

[Isimmo]

There was another thread about something similar elsewhere recently... Next time it does it, eg, key in, no fuel pump, wiggle the ignition key in the barrel, I've seen it before where the feed to 'activate' the fuel pump relay is iffy - Barrel or old immobiliser etc..

Alternatively, run a feed from the coil to the fuel pump relay to activate it.

This will be a temp. fix and don't blame me if it bursts into flames. (highly unlikey to be fair).

But by 20years old the cars have had several alarm immobilisers and the ignition barrel's done a shed load of work...

Worth a punt.

[moomin]

The other thread was mine, fuel relay replacement fixed it, but now i'm thinking maybe it didn't

Not thought of the barrel thing

[mikes2]

Sounds like a failing rotor arm / ignition module.

The fuel pump will cut when the ignition dies

[moomin]

i'd not thought of that I'll check tomorrow, ignition module that little ECU thing?

[moomin]

Found the problem eventually, wasn't the ignition module which i replaced with a motoequip version, was infact a loose connection at the coil, found it by accident when i left the ignition on and knocked it and the relays clicked.

Replaced fuel pump, fuel relay, ignition module all because of a loose contact :|