Volvo Penta 4.3 GL-A question

[GettinBetter]

Basics:- 2001, Volvo Penta 4.3 GL-A with Delco EST Ignition.

I'm looking to connect an alternator with non standard cnnections.
Presently I have the following cable colours on the engine loom:-

• Orange
• Black
• purple
• Purple/white
• green

I have managed to find out that:-

• orange is the battery connection & goes via the starter motor terminal
• black goes to the neg connection on the alternator
• purple
• purple/white
• green

But need to know what the other colours are for?
Any help would be greatly appreciated.

 

[Don S]

Re: Volvo Penta 4.3 GL-A question

Purple, battery sense wire
Purple/white, automatic choke - AC Tap
Green, to fuel pump through a diode, no power to this terminal if the alternator is not charging.

 

[GettinBetter]

Re: Volvo Penta 4.3 GL-A question

Purple, battery sense wire
Purple/white, automatic choke - AC Tap
Green, to fuel pump through a diode, no power to this terminal if the alternator is not charging.

Ok, thanks Don S, may I also take the liberty of asking few more queries on this matter....

purple:- If this is to the alternators sense terminal, may I assume that it goes to the starter solenoid (not the one that energises the starter coil, but the other one)?

purple/white:- Yes, I've checked this for continuity, and it checks out ok.

Green:- I've traced this wire to the fuel pump but its via a relay, & it seems to get its power from the alternator, so which terminal would I be looking for?

 

[Don S]

Re: Volvo Penta 4.3 GL-A question

purple:- If this is to the alternators sense terminal, may I assume that it goes to the starter solenoid (not the one that energises the starter coil, but the other one)?

Nope, the wire is already hooked into the ignition system, so you don't have to do anything to the wire, just hook it up to the sensing circuit on the new alternator.

Green:- I've traced this wire to the fuel pump but its via a relay, & it seems to get its power from the alternator, so which terminal would I be looking for?

The wires are already hooked into the boats wiring harness, as far as what terminal you hook it to on your new alternator, I don't know what alternator you have.

 

[GettinBetter]

Re: Volvo Penta 4.3 GL-A question

Ok, thanks Don S,
Using the info you have supplied, and a little more research on my part I have the noted following.
My purple wire does indeed go to the starter solenoid (via the loom) and is energised when I turn the key to the 'on' position. This circuit has a 118 Ohm resistance, and it also has the choke connected, if we assume the 'excite' connection on the alternator take very little current (correct me if I'm wrong) then the majority of this goes to the choke (i.e. ~0.1A).

I read somewhere that the fuel pump is fed temporarily from this circuit as well, until the oil pressure is up to the norm after which the the supply to the fuel pump is maintained by some other means.
Does/is anyone else aware of this, or can shed some light on it?

Many alternators seem to have a 'excite' circuit that includes a resistance in the form of a lamp, in the case of the 4.3 GL-A there is only a volt meter on the dash, and hence no bulb so no resistance.

My issue here is that if the excite circuit requires resistance to limit the current, then I'd like to use an existing circuit that's made for it, else I'll have to put it in. However to make sure its done correctly, the other circuits must be full understood.

Many thanks for your help guys, (especially you Don S)

 

[Bondo]

Re: Volvo Penta 4.3 GL-A question

Ok, thanks Don S,
Using the info you have supplied, and a little more research on my part I have the noted following.
My purple wire does indeed go to the starter solenoid (via the loom) and is energised when I turn the key to the 'on' position. This circuit has a 118 Ohm resistance, and it also has the choke connected, if we assume the 'excite' connection on the alternator take very little current (correct me if I'm wrong) then the majority of this goes to the choke (i.e. ~0.1A).

I read somewhere that the fuel pump is fed temporarily from this circuit as well, until the oil pressure is up to the norm after which the the supply to the fuel pump is maintained by some other means.
Does/is anyone else aware of this, or can shed some light on it?

Many alternators seem to have a 'excite' circuit that includes a resistance in the form of a lamp, in the case of the 4.3 GL-A there is only a volt meter on the dash, and hence no bulb so no resistance.

My issue here is that if the sensing circuit requires resistance to limit the current, then I'd like to use an existing circuit that's made for it, else I'll have to put it in. However to make sure its done correctly, the other circuits must be full understood.

Many thanks for your help guys, (especially you Don S)

Ayuh,... Yer over-complcatin' this to the ninth degree,...

The Purple wires are the Ignition circuit,...

 

[Don S]

Re: Volvo Penta 4.3 GL-A question

My purple wire does indeed go to the starter solenoid (via the loom) and is energised when I turn the key to the 'on' position. This circuit has a 118 Ohm resistance, and it also has the choke connected,

The purple wire shouldn't have that much resistance in it, and it shouldn't have the choke in it at all. The choke is the purple white wire and works off AC from the alternator as mentioned before.

 

[GettinBetter]

Re: Volvo Penta 4.3 GL-A question

The purple wire shouldn't have that much resistance in it, and it shouldn't have the choke in it at all. The choke is the purple white wire and works off AC from the alternator as mentioned before.

Oh dear my typing over the day when I read it back doesn't always mean what I want it to mean......& sorry, I missed the 'AC tap' as you rightly mentioned in a previous post, that clears up the choke connection.

Must learn to read what you wrote a few more times, I might get it right.

So to recap....

I have managed to find out that:-

• orange; is the battery connection & connected via the starter motor terminal.
• black; goes to the neg connection on the alternator.
• purple; is he sense wire (load sensing taken from the small starter solenoid terminal).
• purple/white; is the choke connection (connected to the AC output on the alternator).
• green; is to the fuel pump, (concept details yet to be found out).

How is the alternator excited? & I'll recheck that resistance.

Thanks a ton Don, you've been a great help, nearly there.

 

[Don S]

Re: Volvo Penta 4.3 GL-A question

I asked before, what alternator are you planning on using that you have to go through all the research. Many alternator will not work on your setup due to that green wire. Wouldn't it be easier to just get the correct alternator, or maybe get your alternator repaired?

 

[GettinBetter]

Re: Volvo Penta 4.3 GL-A question

I asked before, what alternator are you planning on using that you have to go through all the research. Many alternator will not work on your setup due to that green wire. Wouldn't it be easier to just get the correct alternator, or maybe get your alternator repaired?

I don't know just yet what the original one was as this engine didn't have one fitted when I acquired it.

Well I've done the research, and having stripped down the alternator I was planning to use (Delco SI series), I can see that the brushes are clearly NOT shrouded, & neither is there any way of correcting this issue by simple means. So it looks like looking up the part number, and (as you suggest) get a new one, or at least a refurb.

Incidentally, I found this snippet with respect to the green wire to the fuel pump relay....

Alternator (Green) Lead Diode
?This diode prevents current from the assist solenoid/starter relay reaching the alternator regulator during
engine cranking. This diode can fail one of two ways. If the diode becomes shorted (continuity in both
directions), the regulator may be damaged and the alternator might not produce the proper amount of
current. If the diode becomes open (no continuity in either direction), the fuel pump will not run when
the engine is running. After a short time, the engine will starve for fuel.
Assist Solenoid/Starter Role (Orange) Lead Diode
?This diode prevents current from the alternator ?Light? terminal reaching the assist solenoid/starter relay
while the engine is running. This diode can fail one of two ways. If the diode becomes shorted (continuity
in both directions), the starter motor will try to engage while the engine is running. If the diode
becomes open (no continuity in either direction), the fuel pump will not run when the engine is cranking
and may be hard to start.

It didn't help me decide which terminal to connect the green wire to though.

It was an interesting foray, and the information gleamed will come handy later I'm sure.

Appreciate your help, each of the little snippets you supplied allowed me to search on the net using alternative search queries to obtain more details, without which I would have got nowhere.

Regards
GB

 

[Don S]

Re: Volvo Penta 4.3 GL-A question

Well, now we are getting someplace. I assumed you had the old alternator there and could see where the wires hooked on the old alternator and was just trying to get a different kind of alternator to work.
You asked what the different color wires were for, and I told you in my original reply. I thought you wanted to know what they were for, and I answered that.

Your engine came with a Mando 65 A alternator. The Volvo Part number for that alternator is 3857561 .

Here is the wiring diagram for the alternator so you can see what the alternator looks like and what wire hooks where.


View attachment 4.3GL-A.pdf

 

[GettinBetter]

Re: Volvo Penta 4.3 GL-A question

I see....no problem you've been a great help....ah, didn't know the part number, but did zoom in on a diagram I have already, and recognised it as one I have in my garage. Its a bit old but may just need some new bearings. I'll checkout the price of a new one before I mess with this one. Definitely need the P & L2 connections for this engine.

Nice diagram..... its a complete drawing of all the bits I've managed to coble together......So much better

All the best
GB