Another fuel pump buzzing thread!

[CFI]

It finally happened. After driving for 5 hours yesterday my fuel pump started buzzing. The car would buck if I pressed the accelerator pedal down quickly but did ok with a steady pressure. I limped home by filling up every 100 miles then letting the car sit for 20 minutes before continuing on my next 100 miles. Fun!

I see lots and lots of threads about this problem with various ideas on what causes it and how to solve it. I’m mostly curious about the different fuel pumps that are available. Is one of them less susceptible to the hot fuel problem? One that sits lower in the tank maybe?

[Parzival]

I’m going to upgrade to the one from DMC Huston. They are currently back ordered, but are expected to be back in stock very soon


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[CFI]

I’m going to upgrade to the one from DMC Huston. They are currently back ordered, but are expected to be back in stock very soon


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Seems like it’s a good unit. I’m leaning that way as well. I’d really like to be able to drive long distances without issue.

[mr_maxime]

I have a lightly used one available for sale. My old fuel pump had a similar problem but it completely gve out on the highway. I changed it to the DMCH pump in Aug 2017.

It also fixes the bad fuel sender if you have one.

[CFI]

I have a lightly used one available for sale. My old fuel pump had a similar problem but it completely gve out on the highway. I changed it to the DMCH pump in Aug 2017.

It also fixes the bad fuel sender if you have one.

Pm on its way

[DMC5180]

Pm on its way

Sounds like you a broken pickup hose at the bottom of the pump. The pump sucks air, you lose fuel pressure, engine dies, fuel in tank sloshes forward, gets picked by the pump, engine fires up, sloshing fuel the other way. Rinse and repeat, aka stumble and bucking. Keep the fuel tank level above a 1/3 of a tank keeps the pump hose connection submerged in fuel.

5 hrs of driving is pretty long trip, how low was fuel level when it started bucking? What was the OAT and were you using A/C?


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[CFI]

Sounds like you a broken pickup hose at the bottom of the pump. The pump sucks air, you lose fuel pressure, engine dies, fuel in tank sloshes forward, gets picked by the pump, engine fires up, sloshing fuel the other way. Rinse and repeat, aka stumble and bucking. Keep the fuel tank level above a 1/3 of a tank keeps the pump hose connection submerged in fuel.

5 hrs of driving is pretty long trip, how low was fuel level when it started bucking? What was the OAT and were you using A/C?


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5 hours was just half the trip. After the first 5 hours the problem would occur about every 100 miles or so, even at 3/4 tank of gas. Temps in 80’s, AC on. Plenty of gas in the tank when bucking, it wasn’t unporting.

[DMC5180]

5 hours was just half the trip. After the first 5 hours the problem would occur about every 100 miles or so, even at 3/4 tank of gas. Temps in 80’s, AC on. Plenty of gas in the tank when bucking, it wasn’t unporting.

In that case probably hot fuel collapsing the soft pickup hose. I have a spring in mine to prevent that. But on rare occasion When driving in hot temps with low fuel in the tank, I would occasionally get the loud pump syndrome but never the bucking problem. I always knew it was just hot fuel.




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[Bitsyncmaster]

In that case probably hot fuel collapsing the soft pickup hose. I have a spring in mine to prevent that. But on rare occasion When driving in hot temps with low fuel in the tank, I would occasionally get the loud pump syndrome but never the bucking problem. I always knew it was just hot fuel.
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I had the same buzzing and I had the spring in the hose also. It wasn't until I added my fuel cooler that the buzzing stopped. But I've since upgraded to the new style GM pump.

[CFI]

Trying to contact mr_maxime via pm but your box is full.