I have search these forums for the past 3 hours and can't find anything on this problem. I'm running aeromotive regulator with 45 psi on factory injectors with this 400 Walbro pump w/ STM rewire kit. Battery is in the trunk (optima red top) and feeds power directly from it (short distance). Factory fuel rail, lines.

First the positive burned where they were joint to the factory harness plug around 2 inch from plug. Then the ground did the same, and again the positive one more time. I ran out of wire comming from the plug and have a funny feeling it will do it again. The cables haven't caught fire or melt apart, but get really hard and hot, as well as the relay (hot).

anyone has a fuel housing plug with 3-6 inch of wire for sale? lol I think I need one.

thanks in advance.

 

are you blowing the fuse?

 

no, the fuse is not blowing and is 30amps

 

Any1?

 

Bad connections could cause wires to heat up along with too small wire size but with the fact your running a rewire and the positive is running a short distance would leave bad connections.
The thing is the factory plug your spliced into are small wires and that is the spot it's burning up along with the higher amp draw of the 400. I would look into upgrading your connection into the fuel tank.

That would be my guess.

 

Drilling the pump assembly, and sealing it with epoxy to run a thicker pos and neg straight to the pump... ok i can handle that, but should I up my relay to 40 as well as the fuse?

 

Try a 50amp fuse see what happens

 

This is what it says on the walbro 400.

Requirements for installation:

Modification to wiring, fuel lines and fuel module
Upgraded Aftermarket Fuel Pressure Regulator
Larger Fuel Supply and Return Lines
14 Gauge or Larger Electrical Wiring
15 Amp Fuse, 20-25 Amp Recommended
Professional Installation Recommended
NOT endorsed by Walbro for use in E85 fuel

Failure to follow the above noted suggestions while using this pump in a stock factory fuel system will cause severe drivability issues and could lead to damage of the vehicles fuel system.

The pump pulls a max of around 20 amps at 13v.


Then David B
https://www.evolutionm.net/forums/9661329-post297.html

Your fuse size is right. Your wire size is plenty big to the factory plug. So whats left is a good ground with wire sized big enough and the wire size to pump from the plug.

 

2slow, thank you for that answer, I went back to factory pump for now. but will drill the housing later on and run a 14g cable into the tank. will post here my findings later on.

 

Same issues with my 450

My STM kit ****ing melted.

So I went back to stock wiring.

 

If it is melting it is grounding out somewhere before the fuse.

 

that was my first thought, but the positive is running straight from the battery just 1 feet away. lets say 2-3 feet with the relay and loop wire. I'm out of ideas

 

Post up your whole wiring schematic

 

sorry for the late reply, been away for a bit....

positive into relay direct from bat at truck. out positive from relay to factory plug positive at housing (where it melts). ground from relay to ground of factory harness. positive from factory harness to signal of relay. ground of plug at the housing to paint stripped area/bolt for seat belt.


my paint skillz are awesome, I know it.

 

And which wires are burning?
Unplug the relay from it's base and see if it still burns up the wires.