Detailed wiring schematic for 43GL-PEFS

[sasngang]

RE: 2001 Vintage. 43GL-PEFS

Hoping someone can provide a high resolution detailed engine wiring schematic. The previous owner has some wierd things going on, and I'm trying to track them down.
Example: the fuel pump runs even when the relay is pulled out of the circuit! Obviously there's a secondary source of power... but why???

Thanks in advance.

 

[Scott Danforth]

go here and get a manual for your motor and the drive while you are at it. https://www.volvopenta.com/en-us/service-and-support/your-engine/manuals-and-handbooks/

 

[alldodge]

There are 2 diodes going to the relay coil side, and if the one on the ALT side shorts it will keep the relay pulled in. Your pump is running without the relay installed so there is a short or PO rewired it direct because they may have had the diode open

 

[sasngang]

What is the purpose of the ALT side connection? It seems un-needed. Or is that to keep the fuel pump powered after the starter circuit is no longer energized?

 

[alldodge]

What is the purpose of the ALT side connection? It seems un-needed. Or is that to keep the fuel pump powered after the starter circuit is no longer energized?

Yes, you are correct

 

[Scott Danforth]

What is the purpose of the ALT side connection? It seems un-needed. Or is that to keep the fuel pump powered after the starter circuit is no longer energized?

VP uses two diodes vs an oil switch, relay, etc to wire the alternator

 

[sasngang]

RE: 2001 Volvo 4.3GL-PEFS
RE: 4012022718
RE: 3869053

I now understand about the 2 positive feeds to the fuel pump relay using diodes. Someone has wired a second power source into the fuel pump relay actuation circuit, but it seems to be powered any time the battery is connected (obviously not a very functional work-around). I'd prefer to use the OE parts, but cant locate part numbers yet and I'm not certain where the OE diodes are located in the harness. Otherwise... I've ordered some Diodes that should do the trick and will rework the harness back to the OE plan.

Unfortunately the volvo site fails to load a parts manual for this engine SN. I can get the user manual... but it is very generic and offers little help.

If anyone can help with the diode locations... or part numbers, that would be helpful. THANKS!

 

[alldodge]

I don't have a pefs but this is for the GL fuel pump. In most cases the diodes are next to the relay

 

[sasngang]

Thanks to all. I'm hoping to find a part number on one of the diodes so I can order OE replacements.

 

[alldodge]

Search for 1 watt diode and that will be OEM size
If you want get a 2 watt to handle more current

Cost about a buck each or less

 

[Scott Danforth]

Amazon has diodes cheap

 

[sasngang]

Diodes from Amazon... Sounds good.

I have determined the alternator was also bad. Symptom was everytime I hooked up the battery, there was alot of amp draw, and the alternator was getting quite hot (that's not normal). While troubleshooting the alternator, I disconnected every lead except the Positive (B terminal), and the ground (E terminal). And still alot of amp draw at the Alternator.

Anyway, I had another alternator in my parts stash (but condition is unknown)... came from a boat that I parted out a couple years ago.

My question... when should L2 from the alternator become energized, thus sending power to the fuel pump solenoid? (this would be the green wire from L2). I assume that should energize as soon as the ignition switch is turned on. Is that right? I assume also, the fuel pump needs power before the start request is made at the ignition switch.

Could someone give me a quick rundown of the start-up procedure. From Key-off to Key-on to Start request at ignition switch. What is the sequence of events for the fuel pump system? What is to be powered up, when and how?

THANKS!!!

 

[alldodge]

Key off to KO no power to FP relay
KO cranking power from key switch via Yel/Red wire thru one diode which energizes FP relay

Motor starts key releases and removes power from Yel/Red

ALT starts producing power and 12V comes from Green wire to second diode and energizes FP relay

 

[sasngang]

VERY HELPFUL!!

THANK YOU MUCH! I was very much stuggling with the process. Seemed like the fuel pump curcuit should be energized until pressure reading was apparent. Then go to a normally operating condition.

Turns out the Alternator... AND starter (solenoid on the starter) were both bad. The alternator pulled big current as soon as the battery was connected. The newer alternator does not. I will have a helper ID if we are getting power to the FP relaty during starter crank efforts. I hope all is right!

THANKS so much for your insight and help! Fully and completely appreciated! YOU ROCK.

 

[sasngang]

My helper, did indeed help. I've confirmed that when the key switch is moved to the "start" position... we do have Pos 12vdc+ to the coil side, and that energizes the solendoid to run... as it sould!

I will know more once the new starter arrives. I did attempt to recondition the original started ... but no reply from the system.

However the s is base and not allwing me to commuicating to the resto fo the crew. Isn't that so wrong??

 

[sasngang]

My helper, did indeed help. I've confirmed that when the key switch is moved to the "start" position... we do have Pos 12vdc+ to the coil side, and that energizes the solendoid to run... as it sould!

I will know more once the new starter arrives. I did attempt to recondition the original started ... but no reply from the system.

However the s is base and not allwing me to commuicating to the resto fo the crew. Isn't that so wrong??

 

[alldodge]

However the s is base and not allwing me to commuicating to the resto fo the crew. Isn't that so wrong??

Don't understand your question

 

[sasngang]

Honestly I dont understand that earlier message either. I think that was voice to text and I did not check it before sending!!!

 

[sasngang]

OK... here's the end result. The problem was a bad alternator. Once it was replaced, the high amp draw at the battery disappeared, and the fuel pump solenoid functioned properly too. This part of the job is complete! THANKS TO ALL!