[BADCRUZ68]

I am about done digging into this one, the summer is flying by and at my pace its going to be over with before I figure this out. As a last ditch effort I am going to throw out a post in case anyone has feedback before I either tow it somewhere or get someone to make a house call. The fuse that is blowing is killing my fuel pump. I am temped to blame it on the fuel pump just because I can idle/rev it all day in the garage without problems but once I get it on the road under load it will blow in a few blocks. This weekend I moved the battery back to the front to solve some hot start issues most likely related to grounding. Well it fires up just fine now when its hot and the battery well grounded to the engine but still blows the fuse. I hoped it was all related. Below is a pic of the fuse box, the missing fuse is what is blowing. The switched wire you see is whats connected to the fuel pump power, thats been fine for years with no issues. I have also tried a fuse tap directly to where the missing fuse is. Any ideas before I break out the wallet and pay someone for this

 

[BADCRUZ68]

The pump is a Holley Blue with probably 100 miles on it. It does have its own inline fuse, not sure the amps but that one is fine. I do see that the switched wire I am using and have used for a few years is smaller than the power wire from the fuel pump so I wondered about that. I am challenged with this car, its not my skillset so everything takes me 10 times as long. I will look into a relay starting with google to better understand how this can help, I appreciate the feedback!

BTW, the fuse that is blowing is a 20amp

 

[BADCRUZ68]

Motor draws only 3 amps current
7 1/2 amp fuse recommended.

Those are the holly specs Holley Performance Products 110 GPH "Blue" Electric Fuel Pump With Regulator*12-802-1

Let me check spend some time today educating myself on relays and how I could use one to wire this for another go at it. I checked the inline fuse that came with the pump and it is 7.5 amp. I will keep an eye on this thread for anymore comments and see if I can get a relay in town without ordering online. I am not sure what if anything else is running off that fuse, I don't even have a radio in the car.

Edit
I dug out my ron francis catalog and see this part
http://www.ronfrancis.com/prodinfo.asp?number=FP%2D35

Comparing it to Summits part
http://www.summitracing.com/parts/SUM-890023/

Great suggestions though, I see the benefit now that I have done alittle research

 

[BADCRUZ68]

Thanks for the suggestions everyone, I am alot more upbeat about getting this on the road next weekend

 

[BADCRUZ68]

Here is a simple fix/test either way it will do the job. I would use a connection straight to the battery positive terminal with of course a inline fuse run that to a toggle switch so you can power the pump manually through the switch and bypass the fuel block all together. If the fuse block fuse keeps blowing then you have a short to ground somewhere if fuse does not blow then it was related to the fuel pump. Now it has been connected to the battery directly if that inline fuse blows then you know the fuel pump has some high resistance internally causing the issue, fix then is a new fuel pump. If nothing blows then you know that you were running too much off the circuit causing the issue. hope this helps. I am a retired ford master electrical tech with over 20 years experience trouble shooting problems just like yours. Taz

Note relay diagram shown above is a much better permanent option this is more of a fix/test option to diagnose what is the real issue. I would do this before wiring in a relay only to find more is going on.

Thanks Taz, that is exactly my plan. I will hook up a relay power sourced from the battery or the pos side of the solenoid using my current switched power source as the trigger. I currently have a 7.5 amp inline fuse in place, that came with the Holley blue and that never blows.

 

[BADCRUZ68]

Well its been a solid month since my last post on this so you can see I have not been too motivated this summer for car work. I finally installed a relay. I went to Advanced Auto for the relay. Pretty simple setup, the relay had a connection for the switched power , the power source directly from the battery, a ground and then 2 ouput connections, one of which I used for the fuel pump. Again it ran fine in the garage and general slow driving up and down the driveway but as soon as I hit the streets and gave it some throttle she blew a fuse again. This time 2 of them (the top and bottom one in the initial post) No clue whats going on now but I think I will use a toggle switch and avoid the fuse box altogether at least for now to get some drive time before winter.