electric fuel pump interference

[jglover_81]

I just put a msd box on my 72 scamp and have major interference from my electric fuel pump. My fuel pump is set up on a relay and gets power direct from the battery. Even with it hooked direct to the battery I get the interference. With the fuel pump turned off the car starts and runs fine with the pump on the msd fires non stop? Help please!

 

[funwithfuel]

Have you thought about running power and ground from source to consumer in a twisted pair? If you still have the same condition, you could try running a shield wire around the pair. Good luck.

 

[KitCarlson]

The two wire supply is a good idea. Add a capacitor at pump + to - , try 0.1uF, it will help with brush commutation noise.

 

[jglover_81]

I'm going to get some more wire when I go to work tomorrow and try the new wiring

 

[jglover_81]

Rewired the ground on the fuel pump and solved the problem! Thanks guys?

 

[Mad Dart]

You had a ground issue. Ground is usually an issue that most overlook. Good solid grounds are a must.