Fuel Pump will not go on

[B.C. Bob]

I am in the initial steps of starting my car. The first time I hooked up the computer (MS_II) to the car and turned on the key the pump went on for a few seconds and shut off and it has not been on since then. I have checked all the wiring from the computer to the relay board and to the pump and they are all good. The relay switch work, I can feel it go on when I turn the key on. I have checked the voltage on the wire to the pump (grounded to the frame)when the switch is on and the relay is shut and I don't get any voltage.


Does anyone have an idea what the problem may be? All the engine sensors appear to work.

Thanks Bob

[555]

If by turning the key you mean, to the second 'click' without engaging the starter motor then thats perfectly normal!
Think priming pulse is the exact name for it, just removes possible air from the fuel lines.
As soon as you turn the key a bit more and starter goes, the fuel pump should run continually.

[B.C. Bob]

Thanks for the reply, but I think I still have issues. There is no fuel in the tank so the fuel pump has nothing to pressurize, so shouldn't it remain on? If you think of any other solutions let me know. I can get the pump to run if I run a live wire to the + wire on the pump.


Bob

[AR 67202]

no, the pump will run a set time after power on, not measure pressure in any way.

[B.C. Bob]

AR67202, I have only gotten the pump to start up once. When I turn the key off and turn it in again, the pump does not start up. I have only managed to get it to go on once. I had a few other problems which I have worked out. Initially the TPS was not working and I had it wired incorrectly. It looks like the pump is wired correctly. I do have a bad battery which does not have enough juice to start the car. I will get a new one today and give it a try with the new one. I didn't think that a poor battery would give me fuel pump problems?

Thanks for the replies. bob

[eng.student]

I, too am having issues with the pump. I believe it's hooked up properly and it works when touched to a live wire, but not with the megasquirt. Also, when I connect everything to the laptop, except the injectors, all the sensors show up what I think is normal, but when I hook up the injector, nothing works. I am working with a super-mileage, one-man vehicle with a one-cylinder, four-stroke engine for a competition in Indy. Any ideas on how to fix these problems? Any help is appreciated.

[B.C. Bob]

I still have not had any luck getting the fuel pump running thru the relay board. I have an aftermarket wiring kit and it is set up to run an electric fuel pump. Is is OK to run the fuel pump this way and bypass the megasquirt computer.

Bob

[TPI_55_Chevy]

wire a relay to 12 volts and fuel pump pinout for ground. Check to make sure the relay will change state. If not, meter the coil wires on the relay to make sure you have power to the relay. If relay is working read ohms across contact wires on the relay and make sure it is closing when the relay is picked. If that is OK then something is wrong with your pump. Try wiring pump directly to ground and 12 volts and see if it will work. If not your pump is bad. Fuel pumps do not like to run long with no fluid to push....

[B.C. Bob]

I got the pump working tonight. There was a weak solder connection on the relay board. My next issue is I am not receiving a tach signal from the distributor, everything work fine on the stim. I am fuel injecting a chev inline 6 with the old style electronic ignition with a 4 pin discributor. MCII is only being used for fuel control. I wired the tach connection from the distributor to the relay board. Am I missing something?


thanks Bob