Schematic for Fuel Pump Circuit - 2005 Volvo Penta 4.3GL-D

[kingmm01]

I have developed a problem with my Monterey 180FS. The engine will start but shuts down as soon as I release the key. I have read several forums and think the issue is in the fuel pump circuit including the fuel pump relay. I'm not sure if this is powered off the alternator or oil pressure switch. I could clear it up quickly if I had a good schematic.

Engine serial number is 4012144582.

I would love to buy a good service manual.

 

[Don S]

Re: Schematic for Fuel Pump Circuit - 2005 Volvo Penta 4.3GL-D

Oil pressure switch is Mercruiser, Volvo uses diodes in the wiring harness coming from the alternator.

A quick test of the alternator and diode is to remove the L connector on the alternator.
With a jumper wire on the positive battery terminal, touch the green wire in the connector (harness side not on the alternator) and see if the pump runs. If it doesn't run, then the diode has most likely opened. If the pump does work, time to get the alternator tested.

Since it runs for 20 seconds after starting you know the relay works and is priming the carb.

 

[kingmm01]

Re: Schematic for Fuel Pump Circuit - 2005 Volvo Penta 4.3GL-D

Thanks Don....I went out to do your test tonight...but the boat started with no problem. Here's another fact....the only two times it has failed to start....the engine was cold and we had just had a heavy, heavy thunderstorm. The first time the boat had been under a dock but the sides were open and the rain came sideways. Yesterday...it was parked in my driveway and the boat was simply rained on. Obviously the air was thick with moisture.

Does that ring any bells as to what might be dampness sensitive?

Also....if I disconnect the wiring "L" on the alternator or the connection at the fuel pump...the engine still seems to start and run. Does it have enough residual pressure to run for a short period without the pump. I only ran it for 5 seconds or less this evening as I had no water hooked to it.

Thanks for your advice and help.

 

[Don S]

Re: Schematic for Fuel Pump Circuit - 2005 Volvo Penta 4.3GL-D

If the fuel pump ran and had the carb full, it would run at idle no load for about 15 or 20 seconds.

Diodes doen't heal, so a faulty alternator, corroded terminals on the relay, loose wires, could even be a bad relay that has bad timing to make it look like it only works when starting.

Intermittent electrical problems are really tough to find, even for the pro's.

 

[kingmm01]

Re: Schematic for Fuel Pump Circuit - 2005 Volvo Penta 4.3GL-D

Hey Don...The engine wouldn't start today...which was about the 4th of hot dry days so moisture should be no problem. As you suggested....I applied 12V to the green wire from the alternator and the fuel pump started up. The engine seems to immediately go dead when I release the start position on the key...it really doesn't run any time at all. The voltage indicator on the dash reads ~12 when on....and 0 when starting. I'm about ready just to buy a new alternator. Does that sound reasonable?

 

[kingmm01]

Re: Schematic for Fuel Pump Circuit - 2005 Volvo Penta 4.3GL-D

Correction to last post....The voltage meter right now reads 0 (pegged left) when off, on and starting. I think I have yet another conneciton problem.

Hey Don...The engine wouldn't start today...which was about the 4th of hot dry days so moisture should be no problem. As you suggested....I applied 12V to the green wire from the alternator and the fuel pump started up. The engine seems to immediately go dead when I release the start position on the key...it really doesn't run any time at all. The voltage indicator on the dash reads ~12 when on....and 0 when starting. I'm about ready just to buy a new alternator. Does that sound reasonable?

 

[mikeneal]

Re: Schematic for Fuel Pump Circuit - 2005 Volvo Penta 4.3GL-D

As usual Don is right on. Intermittent problems are a lot tougher then "broken. I had a similar problem with my 5.0GL and turned out to be a failing fuel pump. Sometimes the pump wouldn't run even with 12V to it. I suspected it and removed pump and bench tested and about one out ten times the pump wouldn't spin. If you do a bench test don't run pump dry and be aware of using gasoline. I used diluted ATF and made switched electrical away from pump.

 

[Don S]

Re: Schematic for Fuel Pump Circuit - 2005 Volvo Penta 4.3GL-D

Correction to last post....The voltage meter right now reads 0 (pegged left) when off, on and starting. I think I have yet another conneciton problem.

Sounds more like either a bad ignition switch or a defective lanyard kill switch. Has nothing to do with your fuel pump.

 

[kingmm01]

Re: Schematic for Fuel Pump Circuit - 2005 Volvo Penta 4.3GL-D

You have that right Don.....I'm an Electrical Engineer with a speciality in controls and it's still hard...although partly due to a lack of documents.

The ignition switch is good (but changed anyway earlier) and the lanyard is good (jumped it out and made no difference). Same result.

What is the purple wire that comes out oft the alternator in the same connector as the "green wire headed to the fuel pump". Looks like it cgoes to the solenoid and the ignition coil and the connector headed to the front. Is that also a signal from the alternator for something?

I'm going to owe you big time if you help figure this out!

 

[Don S]

Re: Schematic for Fuel Pump Circuit - 2005 Volvo Penta 4.3GL-D

The purple wire is 12V from the ignition switch when the key is in the run position.
Here is the wiring diagrams.

View attachment 4.3GL-D.pdf

 

[kingmm01]

Re: Schematic for Fuel Pump Circuit - 2005 Volvo Penta 4.3GL-D

Well I had 12V on the ignition swith through the lanyard but only 1.77 v at the alternator. I unplugged the 10-pin connector and had 12v coming from the controls. I rang out the wires on the engine side and all were okay. I plugged the connector back in and wala....the engine started right up. Maybe I have found the bad connection.

 

[522]

2005 Volvo penta 5.0 gl cross battery cables replaced alternator will start but will not keep running any ideas?

 

[522]

I am new to this sight could someone tell me where I go to post a new question? thank you

 

[Fun Times]

2005 Volvo penta 5.0 gl cross battery cables replaced alternator will start but will not keep running any ideas?

I am new to this sight could someone tell me where I go to post a new question? thank you

Hi there 522, welcome to iboats!

To start a new topic, just pick the sub forum you'd like to post in and near the top left corner of the page you should see + New Topic. Clicking on + New Topic should bring you to a page similar to this one, http://forums.iboats.com/new-content/58

This may help as well.
http://forums.iboats.com/forum/forum-rules-and-guidelines/587394-how-to-post-a-new-topic

Thanks and good luck.