Fuel Pump stopped working

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I had the MK4 out for a nice drive yesterday. Ran like a dream (Gen1 Coyote). Put it away, and went to start it today and the fuel pump isn't running. Fuses are all good. Any other things that I might want to check before I go through the hassle of pulling the in-tank pump? I replaced the pump shortly after build and have had no issues since then (about 5 years ago) but I can't understand why I might possible going to my 3rd pump when I've only got a total of 8000 miles on this. Any advice or suggestions are appreciated. (Engine and fuel pump from Forte)

UPDATE: The Inertia switch is in the right position and I'm getting good power to the pump. When I tapped on the pump (pump is still in the tank) it would sometimes momentarily run, so I am guessing the pump is failing). Time for a new pump I guess

If anyone has any alternate trouble shooting I should do, or things to try, please lmk

[egchewy79]

possibly a bad wire harness connection that vibrates loose over time.

[Railroad]

I doubt you are guilty of running your tank low on fuel, but air is reported to increase wear on fuel pumps.
Any chance your pick up tube could be sucking air?
Poor connections or low voltage, small gauge wiring?
3rd pump warrants finding the cause, good luck.

[edwardb]

What size fuel lines are you running and what capacity pump are you using? There was a lot of forum chatter early on when Coyote's were first going in about fuel line sizes, stressing pumps, etc. There were several reports of pumps not living long lives. I've used 3/8" supply and return on my builds with 255 LPH fuel pumps. Probably overkill (another discussion...) but for that size pump, Aeromotive said to use 3/8" lines so that's what I did. Plus Pro-M Racing high flow fuel pump hangers, which are true 3/8" in and out. Both builds have been good for a lot of miles. So far.

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What size fuel lines are you running and what capacity pump are you using? There was a lot of forum chatter early on when Coyote's were first going in about fuel line sizes, stressing pumps, etc. There were several reports of pumps not living long lives. I've used 3/8" supply and return on my builds with 255 LPH fuel pumps. Probably overkill (another discussion...) but for that size pump, Aeromotive said to use 3/8" lines so that's what I did. Plus Pro-M Racing high flow fuel pump hangers, which are true 3/8" in and out. Both builds have been good for a lot of miles. So far.


You know.... That may be the issue. I was one of the first guys to do use the Coyote in a Mark IV, well before Factory Five had their kit and instructions all worked out. I used the fuel lines that came from Factory five, and I don't think they are 3/8". I think they were 5/16", and I think the return line was 1/4". I will have to double-check tomorrow. I am using the 255LPH pump from Forte. Burning them out would make sense if the line is too restrictive.

[CDXXVII]

This is why mine failed. If the connection gets hot the posts come loose and the connection inside the tank fails. Same thing happened to a friend of mine.

https://m.youtube.com/watch?v=p5Yq_5cPRoA

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This is why mine failed. If the connection gets hot the posts come loose and the connection inside the tank fails. Same thing happened to a friend of mine.

https://m.youtube.com/watch?v=p5Yq_5cPRoA

Were you able to fix that? Or just needed to replace the pump entirely?

[CDXXVII]

Were you able to fix that? Or just needed to replace the pump entirely?

Replaced with one of these.

https://www.promracing.com/high-flow-fuel-pump-hanger-for-1986-1997-mustangs.html

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Replaced with one of these.

https://www.promracing.com/high-flow-fuel-pump-hanger-for-1986-1997-mustangs.html

I just ordered it now. Thank you!!! Any recommendations on 3/8" braided lines? Or best just to bend steel lines?

[CraigS]

It is much easier to use nycopp; It is raining and my satellite web is too slow but this will give you an idea. It also available in 25 ft roll.
https://shop.advanceautoparts.com/p/nicopp-domestic-nicopp-nickel-copper-brake-fuel-transmission-line-3-8-x-60-cn-660/22190286-P?clickid=W83yySQDGxyLW6WwUx0Mo3Z2UkBwiNwFrQhyR00&irgwc=1&utm_medium=affiliate&utm_source=ir&utm_campaign=2003851&utm_content=471942&c3ch=Affiliate&c3nid=IR-2003851