Where to look for this obvious electrical problem

[doyall]

2007 VP 5.0 GXi-G: Boat was having no problems when taken out of the water last Saturday. Between then and now I 'sanitized' the fresh water system by keeping it pressurized for about three hours then flushing, using the cranking battery. Afterwards, I put the battery on a 2A charger for 8 to 10 hours till it indicated fully charged. Today all systems work (as far as I can tell) except for the trim indicator (trim itself works) and the fuel pump (engine turns over great, just will not crank). All fuses are good and the various relays were rotated and the associated functions are still good. Any ideas as to where to look for this obvious electrical problem? Thanks for any suggestions.

 

[Thalasso]

Re: Where to look for this obvious electrical problem

2007 VP 5.0 GXi-G: Boat was having no problems when taken out of the water last Saturday. Between then and now I 'sanitized' the fresh water system by keeping it pressurized for about three hours then flushing, using the cranking battery. Afterwards, I put the battery on a 2A charger for 8 to 10 hours till it indicated fully charged. Today all systems work (as far as I can tell) except for the trim indicator (trim itself works) and the fuel pump (engine turns over great, just will not crank). All fuses are good and the various relays were rotated and the associated functions are still good. Any ideas as to where to look for this obvious electrical problem? Thanks for any suggestions.

?????

 

[doyall]

Re: Where to look for this obvious electrical problem

?????

The starter engages the flywheel and rotates the crankshaft to force the pistons in an upward and downward motion as it should but there is either no fuel flowing into the cylinders as would be the case if the fuel pump were operating properly or there is no electrical energy to the spark plugs for ignition of the fuel flowing into the cylinders, if there is in fact fuel flowing into the cylinders. In other words, the engine crankshaft will not continue to make rotational motions because there is no combustion of fuel in the cylinders. The engine turns over but will not crank.

 

[dypcdiver]

Re: Where to look for this obvious electrical problem

Turn over = Cranking
Fire = Start

Check you have a spark whilst cranking.
If you do have a spark check the fuel pressure in the line.

 

[Don S]

Re: Where to look for this obvious electrical problem

Today all systems work (as far as I can tell) except for the trim indicator (trim itself works) and the fuel pump

The pumps don't run for 2 seconds when you first turn the ignition key to the run position?

 

[doyall]

Re: Where to look for this obvious electrical problem

The pumps don't run for 2 seconds when you first turn the ignition key to the run position?

When I turn the battery switch to the on position I hear the brief whirr of the (low pressure - rear?) fuel pump. About to get out and try additional diagnoses.

(Original post was done at the end of a long day so everyone please forgive the semantics and other anomalies.)

 

[Don S]

Re: Where to look for this obvious electrical problem

Battery switch should not have anything to do with the fuel pumps.

The fuel pumps should be activated when the ignition key switch is turned to run position, not the battery switch.

 

[doyall]

Re: Where to look for this obvious electrical problem

There is no fuel pump sound when first turning the ignition key on. (I still get what sounds like the fuel pump when switching the battery to 'on'. *If I remember correctly* when I winterized last year using a gallon mixture of gas, 2 cycle oil and stabilizer with a clear hose running to the fuel inlet and switched the battery to the 'on' position the fuel was sucked up to the filter when the battery was switched to 'on'.)

There is no spark to the spark plugs.

I have double checked all the fuses in the box and several in-line and all are good.

A connector that is identified as a "SHORTSTOP" (see pictures 2 & 3) tested positive for continuity and was even jumped (with no success).

The starter relay was changed out for a know good relay.

The only relays I was unable to check are coincidentally the ones that on the top of the fuse box show an icon indicating "fuel" and "spark plugs". (See pictures 1 & 4.) I really don't see how they could have been fried but I suppose anything is possible. Anybody have a way to do a shadetree check of them?

Are there any circuit breakers that I have failed to find that could be the gremlin?

 

[Don S]

Re: Where to look for this obvious electrical problem

Will the engine start? If it does, can you shut it off?

NOTE:
If it does start and will not shut off, pull the ignition relay or fuel pump relay and it will stop. DO NOT just turn off the battery switch to shut off the engine. That will take out your alternator.

Something in the wiring is all messed up, and I'm not sure where to look yet just yet.

 

[doyall]

Re: Where to look for this obvious electrical problem

Will the engine start? ...

No, the engine will not start.

 

[Don S]

Re: Where to look for this obvious electrical problem

There is no fuel pump sound when first turning the ignition key on. (I still get what sounds like the fuel pump when switching the battery to 'on'. *If I remember correctly*

Confirm when you hear the pumps. That is of MAJOR importance to your wallet right now, and should not be guessed at.

 

[doyall]

Re: Where to look for this obvious electrical problem

Confirm when you hear the pumps. ...

I without question hear a whirring at the rear of the engine when I switch the battery to the on position but it is definitely NOT the fuel pump picking up fuel. (What it is can be determined later, if necessary.)

More importantly, there is NO fuel pick-up when the ignition switch is turned to the on position either. There is no fuel pump action at all that I can determine when the ignition is turned on. I did not attempt to start the engine as I have a feeling I know where this is going.

So, I will ask in advance, is there a bench test that can be performed by a reputable shop to determine if the engine control module is toast? Don, if so, does your shop have the capability to do one?

 

[Don S]

Re: Where to look for this obvious electrical problem

I without question hear a whirring at the rear of the engine when I switch the battery to the on position but it is definitely NOT the fuel pump picking up fuel. (What it is can be determined later, if necessary.)

Maybe an electronic bilge pump, but doesn't matter, I'm just glad it wasn't the pumps.

More importantly, there is NO fuel pick-up when the ignition switch is turned to the on position either. There is no fuel pump action at all that I can determine when the ignition is turned on. I did not attempt to start the engine as I have a feeling I know where this is going.

That could be from a number of causes, and just takes some basic electrical troubleshooting (a 12V test light) you up to that.

So, I will ask in advance, is there a bench test that can be performed by a reputable shop to determine if the engine control module is toast? Don, if so, does your shop have the capability to do one?

There are some tests that can be done by you if you want to do them. I seriously doubt the ECM is bad, probably just a wire, fuse, relay or something like that.

 

[doyall]

Re: Where to look for this obvious electrical problem

.. you up to that.


There are some tests that can be done by you if you want to do them. ...

Ready and willing for anything. Any suggestions, or just get me a wiring diagram (got a link to one?) and mark the circuits off as I test them.

 

[Don S]

Re: Where to look for this obvious electrical problem

Yes, I have a diagram I will post. Want to make some additions to it first so it will make it easier to explain.
Plus look for some other info on the testing.
Will be back shortly.

Do you have a DVM ?

 

[doyall]

Re: Where to look for this obvious electrical problem

... Do you have a DVM ?

What's that? Probably not since I don't even know what the acronym stands for. Digital Volt Meter? Yes, I have one.

 

[Don S]

Re: Where to look for this obvious electrical problem

Yes, digital volt meter, get it out and get a jumper wire if you have one. Be right back.

 

[Don S]

Re: Where to look for this obvious electrical problem

This is just a check to make sure the pumps will run. Battery switch on. Key off.

Remove the R4 Fuel pump relay and jumper across terminals D and E in the picture below. The fuel pumps should run. Do they?

 

[Don S]

Re: Where to look for this obvious electrical problem

I think I may have missed the most obvious problem. Is the lanyard kill switch pulled by any chance? That would give you no ignition or fuel pumps.

 

[doyall]

Re: Where to look for this obvious electrical problem

I think I may have missed the most obvious problem. Is the lanyard kill switch pulled by any chance? That would give you no ignition or fuel pumps.

Of course I checked the kill switch ... visually, but after removing and replacing the clip, everything is good to go. It was obviously not seated well. What an idiot I feel like! I cannot tell you how dreadfully sorry I am to have wasted your time. You really are the best Don. I will go sit in the corner now.