1983 ZX Turbo Engine Drops Out

[bandersnatch]

When I first go to start a 83 280 ZX Turbo and place the ignition switch to “on” (not start) the fuel oil pump should run for approximately 5 seconds. Periodically, when I first attempt to start my Z, the fuel pump relay does not pick up right away when the ignition switch is in the “on” position (so if you go to “start”, the engine will turn but will not start). If I leave the ignition switch in the “on” position the relay will eventually pick up and you can hear the fuel pump running. You can then go to “start” and the engine will turn and start with no problem. The car will idle very well. After the car has been running the fuel pump relay intermittently drops out causing the engine to stall from time to time.

I have checked both the fuel pump relay and the electronic fuel injection (EFI) relay and they both checked out O.K. I have also checked the EFI relay input to the CECU (computer) – terminals 27 and 35, both have a voltage of approximately 11.6 volts but the Fuel Pump Relay still doesn’t pick up. I’m not sure on the logic of the computer. Some have suggested that it may be a bad speed sensor on the distributor but I would not think that this would prevent the fuel pump relay from operating for the first five seconds that you have the ignition switch in the start position – since the engine isn’t turning. I have a hunch that it may be the fuel pump control modulator (FPCM) – located just above the CECU computer but I am not sure. After a couple of years, I broke down and brought my car to a Nissen dealer. After a couple of weeks, they still didn’t have a clue (after replacing the EFI Relay – which I told them had already been checked) and when they called me and asked if I would bring my shop manual down for them to look at, I lost confidence in them –told them to button the car up and paid my $185 for nothing. So I’m on my on again.

Any theories out there on what I should check? I don’t feel like laying a chunk of change out for a component just to find out it wasn’t the problem. If you think you know what it may be, give me a clue on how to check your theory to confirm replacing any components would fix the problem

[longlivetheZ]

Sounds like a connection somewhere that isn't quite making contact like it should all the time...something along those lines. Where? I don't know. I've never had this problem, nor have I ever heard of it before. Sorry I'm not any help, but I figured I'd pitch in my 2 cents.