4.3EFI - No gas at injectors

[scrimshank]

I'm still trying to work out why I have no fuel.
I've read the 'sticky' on fuel systems, but the recommendations seem to mostly refer to tests with the engine running - and mine won't start.

Pulled in for gas with 1/4 tank. The engine, which had been running flawlessly up till that time, would not start after fill-up.
The motor will start and run briefly with a shot of ether - but no gas comes out of the injectors. When I turn the key to ignition I can hear the pump run for 2 or 3 seconds. When I disconnect the fuel line from the throttle body, put it into a jar, and turn the key to ignition, no gas comes out of the fuel line. I would expect there to be fuel under pressure after the pump has run briefly - am I wrong about this?
So far I've replaced the fuel filter - pre-filled with gas.
My guess is that I either have a bad pump, regulator, or both. What more can I do to isolate the problem?
Thanks for any help.

 

[Don S]

Re: 4.3EFI - No gas at injectors

4.3EFI doesn't really tell us much, how about a manufacturer, full model and serial numbers. Then there is a chance of an answer.

 

[scrimshank]

Re: 4.3EFI - No gas at injectors

Sorry........Mercruiser V6 4.3L EFI - An Alpha Model I/O. Engine was new in 2002, I believe. 210HP. Serial Number OL694024
Thanks

 

[Danny Mc]

Re: 4.3EFI - No gas at injectors

First step, take neg battery cable off for a few minutes, reconnect try to start again, if no start put a noid on injector to check if it's triggered.
Be sure vacumn line is hooked to fuel pressure regulator, if so, prolly a bad pump.

 

[scrimshank]

Re: 4.3EFI - No gas at injectors

Thanks.
I'll try that now.
But....if the vacumn line is connected to the pressure regulator, and fuel is getting to the fuel pump, shouldn't the fuel line to the throttle body become pressurized when I turn the key to ignition and hear the pump run briefly?

 

[Don S]

Re: 4.3EFI - No gas at injectors

Removing the battery cable is not going to do anything on your Mercruiser. That may be a technique for automotive, but not marine.
You need to get a pressure gauge setup for EFI and actually test the pressures. There are also a number of reasons why the injectors don't fire, not just lack of fuel.
So before you go replacing that $300 pump that may not be bad, you might want to go to the link below, and download the OEM service manual and start reading and understanding what you have.

http://www.4shared.com/document/dKAM4Vg8/Service_Manual_25.html

 

[dingdongs]

Re: 4.3EFI - No gas at injectors

oil pressure switch may be faulty.needs to work to keep pump working.

 

[Don S]

Re: 4.3EFI - No gas at injectors

oil pressure switch may be faulty.needs to work to keep pump working.

The fuel pump is not controlled by the oil pressure switch on EFI engines, it's only used on carbed engines.