Intermittent fuel pump priming

[DougsfastZ]

When the car is cold, I rarely can get the fuel pump to prime with key on. Every once in a while, after going key on several times, I can get it to prime. Most of the time I need to crank the car for over a minute (not continuious) to get the the fuel pump to kick on.

I've removed the fuel pump relay from the passenger fender and cleaned the connectors, with no difference.

Another thing I've seen is when the pump does prime, and the car starts, I don't get fuel pressure for a good 10 seconds. This is also intermittent. Sometimes when it does fire, I get fuel pressure after 1-2 seconds (normal), but sometimes it takes so long the car dies.

How should I go about troubleshooting this? Should I start by replacing the relay? Where can I test on the ECM to check if the relay is getting signal when I go key on?

Thanks

 

[GN Bob]

Clean the ECM pins

On my car, I found that the fuel pump prime pin A1 was corroded. I used electronic contact spray cleaner and a nylon brush to clean all the pins and contacts in the connectors then applied a little dielectric grease on the pins and no problems since.

Just be real careful unplugging the connectors, my 12 volt input pin was so far gone it broke off and I had to run a wire direct to the board.

Who ever the genius was at GM that decided it was OK to orient the ECM with the connectors facing up so water from leaky T-Tops could pool inside the connectors should have been promoted to management.

http://www.gnttype.org/techarea/ecmsensors/ecm3.PDF

Bob

 

[BoostCrzy]

I'm sure in your case its the relay...you can replace it or jump the power to it...there are four female spades in the connector....3 running flat and 1 to the side...jump the middle of the 3 to the 1 ....this will power the pump with the key on.....this is how i run mine.

-Jack

 

[fallacy440]

not to intrude, but i'm having a similar problem where the pump flat out refuses to prime at key on and teh car won't start. mine's an 81 regal with an 84 grand national drivetrain in it. i replaced the fuel pump relay (assuming that on an 84 it's the one closer to the front of the car), but still no start. can you jump both the fuel pump and air conditioner relay of will that fry something? i've been trying to figure this thing out for about a month. maybe the guy at autozone sold me the wrong relay? i was going to try to use the new relay in both places but they're keyed different so i couldn't get it in. how can i test to make sure that the relay's getting power and can i resistance test the wire running from the ecu to the relay to ensure it's not broken? any help you can give would be greatly appreciated.