1G Just blew my 30amp in-line fuel pump fuse!

[Stapl3]

Are you sure he understood you were asking about a backflow valve and not a relief valve?

 

[We're on Boost]

Are you sure he understood you were asking about a backflow valve and not a relief valve?

I really can't be sure because this was only in writing, and it was very brief, like twitter brief.
Their tech data sheet for the DW300 doesn't mention it. It should, if there is one. It mentions the relief valve. It says "PRV Activation (at) 100 psi.

Here is a copy/paste of my question to them:
Hello,
Can you tell me, does the DW300 in-tank fuel pump have an anti-backflow valve built in on the outlet?

And here is the reply I got back on Monday:
Hi Mosfet7,
yes it does
Mark Heinen
Customer Sales Specialist
405-217-0715

So, I think we could do better than that. But it might take a phone call, even then, if they don't have it published in the documentation, can you believe what they tell you?
If we could see it in a picture like you can see the one in the Walbro 255, that would help. I mean the Walbro 255, you can see what looks like the valve core in a tire air fitting, sticking right out to the end of the outlet tube, right? I have a shot where you can just barely see it, because my shot is more sideways, less looking straight in. Here I have the brand new type 255 which has revised plastic moldings on the top for the outlet and the electrical plug. I have a piece of viton 60A (soft) rubber tube over the outlet pipe to replace where most people put an o-ring and a plastic stand-off, and a metal cap. I've been doing it like this into the stock receiver ever since 2009 and it seems to be a good way. The viton is 9/16" OD x 1/4" ID x about 15/16" long. I won't be able to do it this way forever because I only have about 8 inches of it left and haven't seen any place selling it for years. I smear a little bit of Molykote 111 compound on it before assembly to help it go together easier.

Anyway, I suppose the final answer yes or no on the anti-backflow valve question would be if somebody went out to the garage and ran their fuel pumps with a pressure gauge in the regulator, pump it up, then turn it off, and see how fast or slow the pressure comes back down.

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[We're on Boost]

Thanks man! I’ve actually decided to do a 8gauge single 40 amp set up, so again if the fuse blows the motor dies instead instead of limping on 1 fuel pump.

That will work! 8 gauge wire sounds just right. 40 amps will do the job. The 40 amp fuse won't have a lot of headroom, but I think it is the "safe" size, fire safety wise. As long as the fuse form factor is big. Bigger than those little ATC fuses like you had in there before. Because if the fuse and the fuse holder are big, they won't heat up very much. It will be much more robust.
I think then, the main thing to get right is the fuse holder. I would use a fuse holder that is made to take up to 50 or 60 amps and then just put a 40 amp fuse in it.

I haven't used inline fuse holders in this amp range before, but just looking quickly, I see what I would probably buy.
These holders are made to take fuses made to the Bussmann MAX, Littelfuse 299, or Mersen AF3 standards.
The fuses are available from 20 to 60 amps, so your use is right in the middle of the range.
It has 6 gauge pig tails which might sound like overkill, but it's good. All that copper will do a good job of conducting heat out away from the blades. And if this is going to be in your trunk, you don't need miniature stuff!

Anyway here's some links, to the holder, a 40 amp fuse, and a 50 amp fuse, so you can read the specs:

https://www.grainger.com/product/5KDK4

https://www.grainger.com/product/BUSSMANN-Automotive-Fuse-40-A-Amps-6AYE0

https://www.grainger.com/product/BUSSMANN-Automotive-Fuse-50-A-Amps-6AYE1

Actual body length dimension from Bussmann data sheet:

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[1cleangsx]

Hey man I really appreciate all the informative responses! Here’s what my buddy picked up for me.

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[1cleangsx]

It’s an 8gauge in line fuse holder with a 40amp fuse, I’ll try to get installed this weekend

 

[Stapl3]

That's pretty much the fuse I use. What I do is just buy an "amp install kit" off amazon/ebay for 20 bucks and it comes with that and the fat wire and other stuff. That's the way to go about it IMO.

.

I've no way to tell if that has a check valve, but if it does, it's a restriction to flow. A big one. Also your fuse and holder come to 37 bucks before ship/tax??

Is it possible the DW pump is just a walbro/bosch unit with a sticker on the side? Not to undercut them or even throw shade at them, rather to just figure out what the heck you have and are really messing with.
At some point you should just ditch it for a walbro 450 which is under 100 bucks and will give everything 99/100 of us will need.

 

[We're on Boost]

It’s an 8gauge in line fuse holder with a 40amp fuse, I’ll try to get installed this weekend

That looks good. Looks like it uses bolt-down MIDI fuses which I think is a good idea!
The holder looks like it might be a Stinger SPD5801?

 

[We're on Boost]

I've no way to tell if that has a check valve, but if it does, it's a restriction to flow. A big one. Also your fuse and holder come to 37 bucks before ship/tax??

Are those questions for me? If so, the Bussmann HHX fuse holder on the Grainger page is $29 and fuses for it from Grainger are about $8 each. So yes $37.
Prices are all over the place though. Summit Racing sells the same Bussmann HHX fuse holder for $12.99 and NAPA sells the MAX fuses for $3.19 each.

On the check valve, what I meant was that somebody who has a DW300 to look at might actually be able to see the check valve, just like I can see the check valve in the outlet of the Walbro 255.

The other way to tell if your pump of whatever brand has a check valve is to watch what the fuel pressure does when you shut the pumps off. Jeremy could do that with his rig if he wanted to take the time to do it.
You could take video of the regulator with a mechanical pressure gauge in the front port if you really wanted a record of how fast the pressure goes down when you shut the pump off. I've just run the pump from the driver seat with DSMlink, and then when I shut the pump off I rush out to look at the gauge, and by the time I get there (like 5 seconds) the gauge has dropped from 43 to about 30 psi. But from there, the pressure drops much slower. It takes a couple minutes to get down to 20 psi, and then drops even slower after that. So for sure there's an anti-backflow valve there.

As far as I know, most of the intank pumps we talk about in here have an internal check valve. The ones I know of that don't are the Walbro F90000295 and the Bosch BR540.
I might be ok with not having a check valve. I have DSMlink set to run the pump for 5 sec anyway when I turn the key to "On". But I'll probably stick with the regular check valve type.
According to Radium engineering, all the Walbro "450" type pumps have an internal check valve, even the F90000285 "Hellcat". The F90000295 is the "no check valve version" of the Hellcat pump. That pump flows more at fewer amps than the regular Hellcat. So yeah that's pretty cool.

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