I have a 1987 Volvo Turbo wagon that stalled a couple of days ago and will not run. The car has power and spark. It is a fuel issue as I pulled the fuel line and cranked her over and nothing is coming out. Where I am at-
There is power to both fuel pumps (in tank and main) when the fuel pump relay is jumped.

When the ignition switch is turned on the fuel pump relay rapidly opens and closes (can hear it clicking fast) and the fuel pumps both turn on and off rapidly. I have searched everywhere to see if anyone else had had this symptom of the relay rapidly opening and closing and could not find anything.

When the ECU is pulled the relay does not open or close but the pumps can still be powered by jumping the relay (30 and 87/2)

Even when the relay is jumped there is no fuel.

A couple of other things worth mentioning.
1. I have 3 fuel pump relays 2 known functioning ones and one questionable and they all do the same thing

2. when the car died the #7 fuse was blown and has been replaced.

3. when trying to start the car one of the times after it died it emitted a fair amount of smoke, something it never does.

4. I have checked the ground to the intank pump and it is fine.

5. the car has not had any issues that I recall over the last six months and had been running fine.

Any help would be greatly appreciated as this is my daily driver. Could it be a short somewhere that is causing the rapid opening and closing of the relay? Could a blocked filter or line cause a pressure buildup that would in turn cause the relay to react this way? Could it be a bad ECU ( I have a Bosch Jetronic 0280000541 suppose to be pretty reliable)