1998 Larson 233 escape (fuel issue)

[js1987]

I have a 1998 Larson 233 escape deck boat with a 5.7liter gs with Volvo Sx Cobra out-drive. I am having a problem getting fuel to the fuel pump . I checked the fuel relay, have checked all the fuses under the dash put a new fuel pump in it , put a volt meter to the harness that goes into the pump and I am still not getting any voltage to the pump. The only thing I have noticed was that there is a 12.5 amp breaker on the fuel pump mount that seems frozen it says " Ignition protection". Im running out of ideas on it and I am wondering could this be the problem or is there some way to verifiy that this circuit is not working properly . Any help is greatly appreciated

 

[garbageguy]

have you checked the anti-siphon valve? sometimes they get stuck closed

 

[js1987]

I have not would that keep power from getting to the pump . I’m new to the boat but I’m an auto mechanic tho . I figured the pump would make a noise to prime It or am I mistaken? I can check it today just to eliminate it as an option

 

[alldodge]

You have 2 diodes (item 16), check them to see if they are connected and working. A diode will pass current in one direction but not another. If you have a diode scale on your meter shift to it to test.

 

[js1987]

Ok awesome thanks for the diagram helps a lot I did find out I’m getting spark to the ignition protection circuit just no further I’m in the process of going through the rest of it

 

[js1987]

The diodes are fine at this point according to my boat mechanic he checked them a second ago and told me that since voltage is getting to the switch it’s passing the voltage along it’s just dying at that circuit breaker is his theory .what does this ignition protector even do does it kill fuel or spark?

 

[alldodge]

Power to the pump comes directly from the starter batter post thru a fuse (#11). So if there is 12V on the red/purple (#6) wire and at the contact on the relay then power is available on one side of the relay

One side of the coil is grounded thru the black (#6) wire. So to energize the relay and pass power to the fuel pump the coil of the relay is pulled in during the start cycle with 12V thru the yellow/red (#13), then thru the diode and on thru orange wire (#17)

During the run cycle 12V comes from the alternator green (#15) wire, thru the diode.

So the relay stays pulled in passing power to the pump during cranking and run via each diode. If you are getting no power to the pump and you have power at the relay, then its the relay is bad, or the ground is bad.

If you have 12V only during cranking and not run the the ALT diode is bad

Where are you loosing power to the pump?

 

[js1987]

Im getting power all the way to the ignition protection circuit breaker. Im not getting power to the pump from the electrical harness that plugs in it the small 2 prong harness. I tested in while starting and in the accessories position and im not getting any voltage at all I replaced the relay with a factory one and still no luck I did check the anti siphon as was suggested earlier and its fine.. OK gotcha well assuming the diode it bad and my mechanic is not as good as i thought(possibility) how hard is it to replace diodes? Also I really appreciate the info im learning a lot.

 

[alldodge]

The VP diodes look at lot like fuses, they just have a diode symble on them. They are very minimal current carrying tyoe and you can get ones from radio shack which would last much long if not forever

https://www.radioshack.com/products/3-amp-200v-barrel-diodes?variant=5717580037

They would need to be soldered in

 

[js1987]

Would it still be diode even if its getting power to the ignition protector circuit breaker ?

 

[alldodge]

Would it still be diode even if its getting power to the ignition protector circuit breaker ?

If that is item 4 in the drawing then No, if its something else then I have no idea

 

[js1987]

its number 4 in the diagram of course it would be .... crap has a red and red/purple wire going to it ... so that is most likely my problem since that one was frozen completely. either way it has to be replaced.I ordered one from volvo and I guess ill have to go from there and move forward once the part gets in

 

[Bt Doctur]

told me that since voltage is getting to the switch

The ign switch is supplying the power TO the relay. The diode in the ign line passes voltage to the relay to close it and power the fuel pump.. Once the key is released and the motor is running AND the alt is charging it supplies power to the fuel pump thru the diode. The diode in the ign circuit now acts as a blocking diode preventing power backfeeding into the ign system

 

[js1987]

Ok that makes since so since im assuming im going to have to split the wiring and track down the diode is there anything I need to check while i have the loom apart? Do these diodes go out very often?

 

[alldodge]

Some do but the diodes look similar to fuses and will no be inside the harness

 

[js1987]

oh ok most automotive diodes on older vehicles are in the harness ... I suppose this is where the cars and boats differ. Any idea where they would be as far as location wise . like under the dash

 

[alldodge]

They should be on the motor, should look similar to the plastic square fuses and may have a diode symbol on them

 

[js1987]

are they on the same side as the wiring harness plug? also I really appreciate all the help by the way your life saver . I think i am in the general area on the left side of the engine I just hate to think it would be out because its a new engine i just found that out on my boat fax that came in . I still have to do the break in procedure on it. Kinda makes me a little bit worried this issue is minor i hope there arent any other problems i run into

 

[alldodge]

Unsure where they are, just see them in the wiring diagram

Hey BruceB or Scott Danforth or kenny nunez you guys know where those diodes are located?

 

[Scott Danforth]

depends. on some harnesses the diode is in the harness near the device (such as an alternator)

what are we working on?