Sense wire connection on 4G alt

[RedBank]

I need help with alternate place to connect sense wire on my 4g alternator. The yellow sense wire in the pic is currently causing RFI when connected to the alternator charge stud. I have a painless harness and running Sniper with spark control. When I disconnect the sense wire from the stud my RFI stops. Is there a wire/location to connect this sense wire to other than direct to alternator?

Sent from my SM-G781V using Tapatalk

 

[DirtDonk]

Well, you can try another method, but it's more than likely your alternator itself causing the RFI and not just the wire. When you disconnect the wire the alternator stops charging. Hence the loss of the noise.
However, since the original external regulator put a noise suppressor on this very same wire on the original regulator, and because this stuff is mainly a mystery to me anyway, I would not put it past being the wire after all!
Just not sure how sourcing it from a different location is going to change how much noise is being put out near the EFI unit. After all, it still enters the alternator at the same point no matter what.

Anyway, the best (or at least the most reasonable seeming) spot would be the other Yellow wire from the Painless harness that would have been for the original external regulator. It's the same wire with the same function as what you need. You can splice the two together and get the sensing back.

Basically you just need a direct or semi-direct battery connection. It will be hot at all times no matter the position of the key. You can run the wire straight to the battery, to the starter relay's battery side, or literally to any other wire that has power all the time.
But the Yellow wire for the original regulator makes the most sense to me.

Paul

 

[RedBank]

Well, you can try another method, but it's more than likely your alternator itself causing the RFI and not just the wire. When you disconnect the wire the alternator stops charging. Hence the loss of the noise.
However, since the original external regulator put a noise suppressor on this very same wire on the original regulator, and because this stuff is mainly a mystery to me anyway, I would not put it past being the wire after all!
Just not sure how sourcing it from a different location is going to change how much noise is being put out near the EFI unit. After all, it still enters the alternator at the same point no matter what.

Anyway, the best (or at least the most reasonable seeming) spot would be the other Yellow wire from the Painless harness that would have been for the original external regulator. It's the same wire with the same function as what you need. You can splice the two together and get the sensing back.

Basically you just need a direct or semi-direct battery connection. It will be hot at all times no matter the position of the key. You can run the wire straight to the battery, to the starter relay's battery side, or literally to any other wire that has power all the time.
But the Yellow wire for the original regulator makes the most sense to me.

Paul

It probably is the alternator but I'm gonna try connecting it to the yellow wire you mentioned just to see if it helps before buying another alternator. I will post results tonight.

Sent from my SM-G781V using Tapatalk

 

[Broncobowsher]

Ideally the sense wire should go straight to the battery. It is there to sense the battery voltage and adjust the output voltage accordingly. The easy hack is to just loop back to the output. Ignore the voltage drop in the charge wire, which most people oversize anyway.

 

[RedBank]

Ideally the sense wire should go straight to the battery. It is there to sense the battery voltage and adjust the output voltage accordingly. The easy hack is to just loop back to the output. Ignore the voltage drop in the charge wire, which most people oversize anyway.

Any issues if I take it to the Maga fuse between alt and battery or is direct to battery much better?

Sent from my SM-G781V using Tapatalk

 

[DirtDonk]

You can do either. As mentioned the battery is best. But since your mega fuse is probably pretty close to the battery and on at least a six gauge battery cable, there's very little difference. I would at least put it on the battery side of the fuse rather than the alternator side.

 

[RedBank]

Location of sense wire made no difference in interference. Hopefully new alternator will be the cure.

Sent from my SM-G781V using Tapatalk

 

[DirtDonk]

All alternators make some noise. I suppose it's possible for one to make more than most, but not sure. Here again is where are the experts on such stuff can chime in.
Maybe the alternator combined with some noise from the distributor is what's giving you trouble. Have you put in some temporary shielding between the new throttlebody and the rest of the stuff? Something like a sheet of aluminum or whatever?

How is this RFI manifesting itself? Timing problems? Maybe issues with read outs on our screen?

 

[RedBank]

All alternators make some noise. I suppose it's possible for one to make more than most, but not sure. Here again is where are the experts on such stuff can chime in.
Maybe the alternator combined with some noise from the distributor is what's giving you trouble. Have you put in some temporary shielding between the new throttlebody and the rest of the stuff? Something like a sheet of aluminum or whatever?

How is this RFI manifesting itself? Timing problems? Maybe issues with read outs on our screen?

RPM reading is all over the place and I realized tonight there is a terrible whine in the stereo as well.
Tonight I removed unused wires from the connectors, wrapped wires individually with Faraday tape, moved the coil over to the drivers fender and separated/sorted plug wires and things have greatly improved. The alt has a lot of miles on it so I think a new one will make a big difference.
My biggest problem now is going to be the air cleaner. When it is placed on the data really goes crazy. I've looked for a low profile plastic air cleaner but 4" is all I can find and that won't fit under hood.

Sent from my SM-G781V using Tapatalk

 

[DirtDonk]

If you find an air cleaner you like that fits the engine, you could probably toss the 4 inch filter that comes with it and put it in a two or 3 inch filter replacement.
Loses a little efficiency, but at least it might clear the hood.