Why did my electric fuel pump die?

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EastAustinSawdust

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I have a 6 month old Mallory Series 110 fuel pump. This week it died. Checked all wiring, fuses, checked the controller (Revolution Electronics controller runs runs pump for 3 sec when ignition in accessory position). Everything seems ok. It’s the pump itself that is shot. Connect the leads straight to the batt, nothing. Checked it with a multimeter and the circuit appears broken (infinite resistance).

What the heck could have caused this, other than just poor manufacturing? My current top picks:

1. It’s just a bad pump.
2. Somehow the Revolution Electronics controller harmed the pump. I find this hard to believe, because the controller worked fine for several months and still appears to work.

That’s all I got. Keen to hear your thoughts.

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Big Chip

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Not sure about that pump but generally they like to push the fuel and not pull it so it should be as close to the tanks as possible. I’ve heard of failures from overworking the pump trying to pull fuel all the way to the front of the truck.
 

Turbo4whl

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Like Kevin stated, the pump should be close to the fuel tank and as low as possible. Issue here is that usually means the pump is close to the exhaust system. Heat also will destroy an electric pump. If needed add a heat shield, but keep the pump low and near the tank.
 

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I know that the LS swap crowd avoids external pumps like the plague. Word on the street is that their death is very predictable. They don't last long.
I only ever tried one once, and it was when I swapped a tuned port motor into an 85 S10 Blazer. It lasted only a few months. I went to an internal one after that.
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Also, a return line helps electric pumps to run cooler.
 

EastAustinSawdust

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The pump is right next to the fuel tank, so it shouldn’t be working too hard to get fuel. It has a filter between it and the tank, which was installed with the pump (6 months ago) so it should be fine. And if the pump was starving for fuel, I’d assume I would have experienced some sort of engine performance side effect, like sluggish acceleration or something, right?


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Turbo4whl

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What about the heat, is the pump near the exhaust?
 

EastAustinSawdust

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Issue here is that usually means the pump is close to the exhaust system. Heat also will destroy an electric pump. If needed add a heat shield, but keep the pump low and near the tank.

Huh. It is in the vicinity of the exhaust, but still like a foot away. That seems like plenty of room to me...would you disagree?


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Turbo4whl

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Huh. It is in the vicinity of the exhaust, but still like a foot away. That seems like plenty of room to me...would you disagree?


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Yes. You be the judge though. Drive awhile, traffic/ highway what ever, get the truck hot. After an hour reach up between that hot exhaust pipe and touch the pump.

Heat shields do work, for whatever purpose, or the factory would never bother using any.
 

EastAustinSawdust

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Will do, once I rebuild or replace the pump. Thanks!


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K201979

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I have an old no name(on the truck when i bought it) electric pump that’s been running fine(knock on wood) for the three years that I've had it. It sits just the other side of the frame rail from exhaust I can snap a pic at lunch tomorrow if that helps.
 

SirRobyn0

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My opinion, you probably just got a bad pump, but a heat shield would be cheap insurance. We all know electric pumps should be as close to the tank as possible, but I know a guy with an old jeep that has his pump mounted on the inner fender well, and the pump handles it. He probably replaces his about every 5 years or so from what he has told me. Dirty fuel, to much restriction. Yes, I think I would tend to believe an electric pump would prefer the engine have a return line, but I don't think it's a requirement. Those are my thoughts any how.
 

HotRodPC

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Not sure about that pump but generally they like to push the fuel and not pull it so it should be as close to the tanks as possible. I’ve heard of failures from overworking the pump trying to pull fuel all the way to the front of the truck.


I didn't read the thread soooo, but Yep, 2nd post in, this right here would be my piece. Need to have the E pumps as close to the tank as possible for good long life. If you had the pump under the hood, I'd say you likely overworked the pump.
 

HotRodPC

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Back in the day on my old street strip truck. I was able to get an E pump out of a pull a part from a carbed ricer car. I did have it hooked up and mounted under the hood. BUT, since they are flow through, it was on a toggle switch and only used when needed and my manual on the block pump was my main pump. That engine ran very warm with that big cam driving in the Los Angeles stop and go traffic. Then I'd stop in the store to get some beer for the long 1.5 hour sitting in traffic drive home, then the truck didn't want to start when I got back in it. VAPOR LOCK !!! So I'd turn on the E pump to push the fuel on through the vapor and it would start right up and then shut the pump back off. It also came in handy when racing to make sure I had enough fuel backing up the manual pump when racing then shut it back off after the race. Then when the manual pump took a dump, I was able to drive full time on the E pump for a few days til I got the manual pump replaced. It was nice having the back up option on a toggle switch.
 

EastAustinSawdust

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Praise Jegs. They sent me a new one for free.

reinstalling this weekend. Any suggestions for materials or designs for making an exhaust heat shield?


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