Good morning everyone,i just bought a (used very little) lift pump for a spare and was wondering if i could wire this back by tank to assist pump on motor.If the pump on motor went out could the other pump pick up the slack or would the pump on motor be too restrictive.Thanks for any input.

 

you bought another stock lift pump or an aftermarket pump?

You can push through the stock LP to an extent, but investing in a fuel pressure gauge would net you a lot more return for your money and time than installing an extra stock LP inline.

 

I had the intank pump when I first had my truck, and it was very weak. To get me by, I installed a block pump until I could get a better pump. I could not run one or the other, both had to run or there would be too much restriction from one or the other. It would make 29PSI at idle, but drop to about 22 while driving around and 17 at WOT. Shows how little flow they produced.
If you want to install another one as a safety, they can not be in series. A fuel pressure gauge is a really good idea.

 

You could make it work by adding some tees and check-valves. But the extra fittings would cut the flow and aerate the fuel. I have an electric pump feeding my stock lift pump and it works pretty good, but I've got oversize lines and minimal fittings.

 

You can do it. Its what guys called "pusher pumps". Guys have used two OEM lift pumps or one OEM and one aftermarket. This effort was tried before it finally was realized that no matter, its just worth it to buy an aftermarket fuel pump setup thats able to do the job on its own instead of trying to make something up. One thing you're going to possibly need to consider is that the ECM is not only telling the OEM lift pump when to pump and how much to pump but the ECM is also supplying all the power too. For that reason you may need to set up a relay so the second pump isn't being powered by the ECM but simply being told when to pump. This way you dont overload the ECM.

 

I've been running mine with an electric pump feeding the lift pump. Seems to work fine but you always have to run them both. From what I've researched on here though, there is a better way to set it up if you plan on running two. If you run them inline like I've got, one of the pumps will eventually wear the other pump out.

 

Thanks guys for all the replies.Very good info.

 

Sell em both and get a AD/FASS