328 fuel pump relay

The fuel pump start relay energizes the fuel pump at startup. Then the other relay takes over once the car is running.
Alden

 

It's more accurate to say that the FUEL PUMP START RELAY operates the FUEL PUMP RELAY:

During starting (key in Pos III) = the FUEL PUMP START RELAY provides +12V to close the FUEL PUMP RELAY (and operate the fuel pump) regardless of the state of the safety switch on the airflow metering unit.

During engine running (key in Pos II) = the FUEL PUMP START RELAY provides +12V to close the FUEL PUMP RELAY (and operate the fuel pump) only when the engine is actually drawing in air and the safety switch on the airflow metering unit is open. If the engine stops running (like in a crash) and the key is still in Pos II, the safety switch closes and the FUEL PUMP START RELAY does not provide +12V to the FUEL PUMP RELAY = the fuel pump does not run (which prevents having fuel at high pressure spraying everywhere after a bad crash). This is also why the CIS fuel pump does not run with the key in Pos II when the engine is not running.

 

You're right Steve, I was going to expand on my explanation but just tried to keep it simple, thanks.
Alden

 

Either one (if you mean the engine does crank over, but does not fire up). Easiest thing to do is just temporarily "borrow" a different ...101 relay for the FUEL PUMP START RELAY and a different ...113 relay for the FUEL PUMP RELAY. If still no joy, remove the FUEL PUMP RELAY and use a jumper wire to connect the female 30 terminal in the fuel pump relay socket to the female 87 terminal in the fuel pump relay socket like this:

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The fuel pump should run (even with the key "off") -- if it doesn't = you have some other problem (and not a relay problem).

 

Just replaced both relays. They're about 10 bucks each!
Alden

 

You should hear a continuous buzzing/humming when the jumper is in place. Either your fuel pump is dead or has a wiring problem. One thing to check in the 328 wiring is this connection in the passenger footwell for discoloration/burning:

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Otherwise, you're at the point of applying +12V and ground directly to the fuel pump terminals to see if it runs/buzzes/humms. Good Hunting!

 

I believe with left rear wheel off and the fender liner removed is the usual approach to do 328 fuel pump stuff, but others may feel differently -- this isn't an exact science .