took the "S" terminal off my starter and tried to crank fuel pump did not run

bluecollerboater

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took the "S" terminal off my starter and tried to crank fuel pump did not run

I have a 5.7gipmda which has been hard to start since I bought it in March. It will crank until oil pressure builds then start. I got a suggestion from another forum to take off the "S" wire from the starter and see if the fuel pump runs while cranking. What I got was the initial 2 second prime from the pump with the key on not running. when I tried to crank it I heard the starter relay click but the pump did not run. I would imagine the pump should run while cranking the starter. What would cause it not to? I have gotten this far but I do not know what to do next.
 

Don S

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Re: took the "S" terminal off my starter and tried to crank fuel pump did not run

Re: took the "S" terminal off my starter and tried to crank fuel pump did not run

]I have a 5.7gipmda which has been hard to start since I bought it in March. It will crank until oil pressure builds then start. I got a suggestion from another forum to take off the "S" wire from the starter and see if the fuel pump runs while cranking. What I got was the initial 2 second prime from the pump with the key on not running. when I tried to crank it I heard the starter relay click but the pump did not run. I would imagine the pump should run while cranking the starter. What would cause it not to? I have gotten this far but I do not know what to do next.

You have an EFI engine, not a carbed engine. When you turn the key to run, the pumps run for 2 seconds and stop. Then when you turn the key to start, the pump relay is energized and the pumps should come on, but if they don't receive a confirmation of ignition, the pump relay will shut off. This only takes a second.
Since you don't have the starter hooked up, you have no ignition reference signal, so no fuel pump operation from the relay.
 

bluecollerboater

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Re: took the "S" terminal off my starter and tried to crank fuel pump did not run

Re: took the "S" terminal off my starter and tried to crank fuel pump did not run

Thank you.
 

bluecollerboater

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Re: took the "S" terminal off my starter and tried to crank fuel pump did not run

Re: took the "S" terminal off my starter and tried to crank fuel pump did not run

Is there any way to test if the pumps are running while I am cranking?
 

bluecollerboater

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Re: took the "S" terminal off my starter and tried to crank fuel pump did not run

Re: took the "S" terminal off my starter and tried to crank fuel pump did not run

Or another post suggests there may be a start by pass circuit. Where is this circuit and how would I test it?
 

Don S

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Re: took the "S" terminal off my starter and tried to crank fuel pump did not run

Re: took the "S" terminal off my starter and tried to crank fuel pump did not run

Is there any way to test if the pumps are running while I am cranking?

Hook up a fuel pressure gauge. if the pressure builds, the pumps are running.

Or another post suggests there may be a start by pass circuit. Where is this circuit and how would I test it?

What by-pass circuit are you referring to? Could you explain what this by-pass circuit is supposed to do?
 

bluecollerboater

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Re: took the "S" terminal off my starter and tried to crank fuel pump did not run

Re: took the "S" terminal off my starter and tried to crank fuel pump did not run

Re: Mercruiser with Volvo accessories hard to start.
Originally Posted by Bluecollerboater
Where is the start by pass circuit?
I don't know your system completely.
What would cause the fuel pump not to run while cranking?
The start-by-pass circuit may not be functioning.
You'll want to test for fuel pump power/current while cranking.
This means both sides....... for the actual By-Pass circuit and for fuel pump relay power.

And if you want to, you could actually disconnect the field wire to the starter motor to eliminate it from operating while you do the testing.Typically a Start-by-pass circuit will begin at the starter motor solenoid, either at an "R" or "I" terminal.

This becomes energized during starter motor action.... and lets go immediately upon starter motor disengagement.
Meanwhile, the low oil pressure switch continues the fuel pump relay operation once above XX psi.

This is a cut and paste from another forum
 

Don S

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Re: took the "S" terminal off my starter and tried to crank fuel pump did not run

Re: took the "S" terminal off my starter and tried to crank fuel pump did not run

Re: Mercruiser with Volvo accessories hard to start.
Originally Posted by Bluecollerboater
Where is the start by pass circuit?
I don't know your system completely.
What would cause the fuel pump not to run while cranking?
The start-by-pass circuit may not be functioning.
You'll want to test for fuel pump power/current while cranking.
This means both sides....... for the actual By-Pass circuit and for fuel pump relay power.

And if you want to, you could actually disconnect the field wire to the starter motor to eliminate it from operating while you do the testing.Typically a Start-by-pass circuit will begin at the starter motor solenoid, either at an "R" or "I" terminal.

This becomes energized during starter motor action.... and lets go immediately upon starter motor disengagement.
Meanwhile, the low oil pressure switch continues the fuel pump relay operation once above XX psi.

This is a cut and paste from another forum

The first sentence has me wondering what you have there. Mercruiser with Volvo accessories?? What do you have really? Is this just a Mercruiser long block dresses in your Volvo trim?

Since you have only called this a Volvo here, I will assume it's just a Volvo with a Mercruiser long block.

There is no "bypass" circuit with an oil pressure switch used by Volvo, that is a Mercruiser setup.

So following that, the poster that posted about the bypass circuit must not know much about a Volvo EFI system, probably a Mercruiser person used to carbed engines.

Did you mention that you have EFI in the other forum? Seems you give some details in one forum and other details in this one.
 

bluecollerboater

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Re: took the "S" terminal off my starter and tried to crank fuel pump did not run

Re: took the "S" terminal off my starter and tried to crank fuel pump did not run

You are correct. It is a 1987 mercruiser mie 260 block with all the accessories from a volvo 5.7 gipmda including the tbi, alternator, water pump, manifolds and risers. The intake manifold is also volvo. It has all the sensors from the volvo( coolant temp switch, oil pressure switch and knock sensor). Yes I did mention it was a throttle body injection on the other forum. I added to a post that I started last week. Maybe the people replying did not read the whole post, just the new part.
 

Don S

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Re: took the "S" terminal off my starter and tried to crank fuel pump did not run

Re: took the "S" terminal off my starter and tried to crank fuel pump did not run

Maybe the people replying did not read the whole post, just the new part.

Possible, or they don't know there is a difference.
 

bluecollerboater

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Re: took the "S" terminal off my starter and tried to crank fuel pump did not run

Re: took the "S" terminal off my starter and tried to crank fuel pump did not run

So I guess there is no by pass circuit?
 

Don S

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Re: took the "S" terminal off my starter and tried to crank fuel pump did not run

Re: took the "S" terminal off my starter and tried to crank fuel pump did not run

So I guess there is no by pass circuit?

Nope, see reply #2 in this thread for how your's works.
 
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