Fuel Pump feedback to MSD box
Thread Starter
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Post Fiend
Joined: Jan 2004
Posts: 6,610
Likes: 2
From: Northwest, Arkansas
Fuel Pump feedback to MSD box
Ok here is the problem and I hope someone out there can give me a clue cause I tried everything I can think of.
I installed a duraspark ignition into an 84 BII using a MSD 6A ignition box, later I had to put in an electric fuel pump. Now When I turn on the fuel pump I get a high pitched pulsing sound from the MSD box. If I turn off the pump the sound from the Box goes away or if I unplug the MSD it goes away. Here is what I have tried and still doesn't work right.
Pump wiring straight to the battery (hot and ground)
Pump wired to switched source
Pump wired through a Bosch relay
Box wired through a relay
Box wired away from pump wires
Any ideas would be greatly appreciated.
I installed a duraspark ignition into an 84 BII using a MSD 6A ignition box, later I had to put in an electric fuel pump. Now When I turn on the fuel pump I get a high pitched pulsing sound from the MSD box. If I turn off the pump the sound from the Box goes away or if I unplug the MSD it goes away. Here is what I have tried and still doesn't work right.
Pump wiring straight to the battery (hot and ground)
Pump wired to switched source
Pump wired through a Bosch relay
Box wired through a relay
Box wired away from pump wires
Any ideas would be greatly appreciated.
Thread Starter
|
Post Fiend
Joined: Jan 2004
Posts: 6,610
Likes: 2
From: Northwest, Arkansas
Thanks but like I said up above I even tried to wire the hot and ground straight to the battery and still had the feedback, even had the MSD box grounded straight to battery.
Moderator
Joined: Jan 2001
Posts: 56,983
Likes: 2,736
From: Virginia
I would try one of those noise capacitors on the fuel pump hot wire and or the msd hot wire feed.
These are those little metal cans that you see here and there, sometimes mounted next to the alternator regulator. I think I looked it up online at one of the local parts stores for someone on here before, and the parts stores carry them. See if one or two of these will bleed off any high frequency noise to ground. The wire goes to the hot wire, and the outside metal part goes to a good ground.
If you know someone who is electronically inclined, they may be able to help you find some other capacitors or something to help bleed off any noise.
MSD has a very good site too. You could look around in there and maybe ask them a question about it.
These are those little metal cans that you see here and there, sometimes mounted next to the alternator regulator. I think I looked it up online at one of the local parts stores for someone on here before, and the parts stores carry them. See if one or two of these will bleed off any high frequency noise to ground. The wire goes to the hot wire, and the outside metal part goes to a good ground.
If you know someone who is electronically inclined, they may be able to help you find some other capacitors or something to help bleed off any noise.
MSD has a very good site too. You could look around in there and maybe ask them a question about it.
