Fuel delivery

[alldodge]

If you think it would be worth it to buy factory I will but guessing they are not cheap and I get why..

It would not help to get the factory manual IMO
Need to understand electricity to be able to understand the issues with voltages

 

[rickasbury]

It would not help to get the factory manual IMO
Need to understand electricity to be able to understand the issues with voltages

Obviously I'm not going to be an electrical engineer..but if I can test the plug and know if I have power it would answer a lot of questions.

 

[rickasbury]

Key ON, MPR energizes and sends power thru out ECM and to FP relay

ECM powers up, hear beep and then applies ground to pin A-19 for couple seconds which powers on FP

If you put meter on pin A-19 or pi 86 of FP relay before key is turned ON you will see 0V. Key ON, 12V to relay coil and "may" see 12V then 0V when ECM energizes relay to power FP relay. When ground is removed will see 12V again

If you don't see 12V at any time then the fuse is blown, MPR is not energizing, bad connection, or relay coil is burned out

Boost pump is powered by the same FP relay. It's a add-on kit supplied by Merc to help stop vapor lock

The Boost pump can be removed and run without for testing with a bypass

So, I think I can handle this with a little guidance. I have a meter..std type probe....so to probe that relay is there something attached to it to get into the pin area? And where do I ground it? Since the pump in the cool fuel appears to be running I don't think it will be the relay...I'm not understanding why I can't check for power at the pick up pump connection to rule out everything in the circuit behind the plug but we have determined I'm not an electrical guy and will follow your suggestion with a little guidance and learn!

 

[alldodge]

You can check at the pump, which is good enough. Most like the relay because it's easier to get to. If pump does not turn on then need to check at relay


Use block or bat ground

 

[rickasbury]

You can check at the pump, which is good enough. Most like the relay because it's easier to get to. If pump does not turn on then need to check at relay


Use block or bat ground

I have the pump on my bench- so I can you my volt meter and hook up to the two pins on the plug and turn the key, check for voltage? I do want to understand checking at the relay...which will tell me more if there is no voltage at the plug. I would need the pump to check at the relay correct? Thanks- hard to find shops I'm trust..

 

[alldodge]

I think this is most simple

Have someone turn the key ON and you have your hand on the cool fuel pump under the port side motor mount. Does it turn ON for a couple seconds

If YES - attach fuel pressure gauge to furl rail and key ON again and see if pressure gets to 43 psi

If NO - Check fuse, should be at least 3 under rubber cap

If Fuse is good - Remove both relays on the motor from their brackets. Removal can have an issue, look close of how to

With relay up side down note pin locations

Pins 30 and 86 should have 12V on them with key turned ON and remain live even after pump stops running

If 12V is found on 30 and 86 and pump does not run then either relay is the issue or need to check connection between ECM and relay,

 

[rickasbury]

I think this is most simple

Have someone turn the key ON and you have your hand on the cool fuel pump under the port side motor mount. Does it turn ON for a couple seconds

If YES - attach fuel pressure gauge to furl rail and key ON again and see if pressure gets to 43 psi

If NO - Check fuse, should be at least 3 under rubber cap

If Fuse is good - Remove both relays on the motor from their brackets. Removal can have an issue, look close of how to

With relay up side down note pin locations
View attachment 388089
Pins 30 and 86 should have 12V on them with key turned ON and remain live even after pump stops running

If 12V is found on 30 and 86 and pump does not run then either relay is the issue or need to check connection between ECM and relay,

That's awesome info I'm sure someone else will find and use..I will do some studying. Thanks-

 

[nola mike]

I think this is most simple

Have someone turn the key ON and you have your hand on the cool fuel pump under the port side motor mount. Does it turn ON for a couple seconds

If YES - attach fuel pressure gauge to furl rail and key ON again and see if pressure gets to 43 psi

If NO - Check fuse, should be at least 3 under rubber cap

If Fuse is good - Remove both relays on the motor from their brackets. Removal can have an issue, look close of how to

With relay up side down note pin locations
View attachment 388089
Pins 30 and 86 should have 12V on them with key turned ON and remain live even after pump stops running

If 12V is found on 30 and 86 and pump does not run then either relay is the issue or need to check connection between ECM and relay,

He's got the pump on the bench...why not just hook 12v to it?

 

[alldodge]

He's got the pump on the bench...why not just hook 12v to it?

Don't care, weather it runs on the bench is not the issue, it's if it runs on the motor

 

[rickasbury]

Don't care, weather it runs on the bench is not the issue, it's if it runs on the motor

I get with alldodge is saying..if there is a problem with relay or somewhere else it's not going to work. There are two relays there by where the fuses are, which one is FP relay or is there one for each pump? I'm going to bring the boat home am and want to be able to jump on this!

 

[Scott Danforth]

there is a relay for each pump. see the schematic in post #9

 

[alldodge]

there is a relay for each pump. see the schematic in post #9

No, one is FP which turns on both pumps. The second one is main power

 

[rickasbury]

No, one is FP which turns on both pumps. The second one is main power

Ah...interesting ..thanks! I will report back my sucess-

 

[rickasbury]

No, one is FP which turns on both pumps. The second one is main power

How do I know which is which?

 

[alldodge]

By the color wires on them. In post 9 the colors are there. They are the same relays and can be swapped.

If FP relay is not working, swap the two then turn key on, if you don't get things to power up then FP relay is bad, if it does power up the re n relay is good and problem is something else

 

[rickasbury]

By the color wires on them. In post 9 the colors are there. They are the same relays and can be swapped.

If FP relay is not working, swap the two then turn key on, if you don't get things to power up then FP relay is bad, if it does power up the re n relay is good and problem is something else

In the diagram it says one is a fp relay and one is the main power relay there are not 2 fp relays in that diagram?

 

[alldodge]

In the diagram it says one is a fp relay and one is the main power relay there are not 2 fp relays in that diagram?

Agree post 32

No, one is FP which turns on both pumps. The second one is main power

 

[rickasbury]

Agree post 32

Yep, I got that- how do I know which one is which? The layout says a fp relay,the other is not-

 

[alldodge]

If your unable to see the wire colors, put hand on relays, turn key on MPR will turn on and not back off. FP relay should turn on and back off after a couple seconds

 

[ROY WILLIAMS]

I seem to be having a fuel "delivery" problem-
2006 MPI 350/5.0, bravo lll.
Short recap, boat seldom used over 3 years and started to get it back to the water. 320 hours.

Pumped out and desposed of 75 gallons of fuel. Water and some crap in the fuel and that was pumping out through the fuel rail when I took a sample.
Ended up replacing the starter trying to crank- it was at its end. New starter in, two bolts, two hot wires and one small post that goes to the alternator I believe.
As the starter was dying it sounded like it wanted to start but stumbling.
New starter cranking but getting no firing.
I thought I only had one fuel pump but turns out I have the cool fuel- I know it's common, just never had that problem.
I dropped the fuel water separator and it was dry. I suspect the engine was trying to start on the fuel that was left in it, so the high pressure pump in the cool fuel on the port side of the motor would be working? I pulled the regular fuel filter to make sure no restrictions going back. That low pressure pump is like 600 bucks. The high pressure one I did order- it was 45 bucks which is pretty much a std gm pump.

So how does this system work?

When t turn the key I get the wirr..that must be the high pressure pump trying to load up the fuel rail?

What energizes the low pressure pump? It just pumps into the fuel water separator to be sucked out of there by the high pressure pump? How do I test the plug for power? What triggers that pump to pump fuel?

Fuses- on the top of the motor by that push button master selonoid, there is a flat fuse bar with 3 yellow/10 Amp fuses that at least one I'm told is fuel pump related. They are all fine. There are two other relays I have no clue what they are or how to check them.

While it might be a coincidence I can't help lean to something electrical...when the starter gave up the ghost it made a terrible electrical short kind of sound...like an electric chair in a horror movie...but nothing tripped that I can find..I don't recall undoing any other wires to get the starter out but the timing is off

I don't know if buying a manual would do me any good? It would have to be pretty basic to be of use. If I got a mobile vessel view, would that possibly give me a code? I know it won't for fuel or fuel pressures but if something else was zapped?

Sure looking for some ideas!

I was the 3yrs ago , 75 gallons of the gasoline , it is a mess of the gasoline clean it of the tank , gas lines and the engine fuel items ......
the boat is a lot of water inside it and the electrical issues ..