Fuel pump buzzing cure?

[Bitsyncmaster]

I have found through testing that the fuel pumps tend to buzz when the heat of the fuel in the tank goes above 125 degrees F. I also found through testing that most of the heat gained in the tank is due to the return fuel line. So I made a cooler on the return line. Still have yet to do a long hot drive to see it that has curred the pump buzz.

But on the wideband forum I participate in, a link was posted about a PWM fuel pump controller.

http://www.madhu.com/content/Main/FuelPumpController

I've been thinking about using a PWM controller for reducing the returned fuel for some time now. But with our cars you still get some returned fuel via the FV controlling the fuel mixture. So I did not pursue the PWM controller.

Interesting note in the link. "When the fuel is above 120 degree F, the pump will cavitate.". Looks like that is what I found caused the pump to buzz.

[sean]

. I also found through testing that most of the heat gained in the tank is due to the return fuel line. So I made a cooler on the return line.
I don't recall you talking about this before. Did you go with a heat exchange unit like Grady's tranny cooler or some sort of mini radiator? Where did you install it?




Interesting note in the link. "When the fuel is above 120 degree F, the pump will cavitate.". Looks like that is what I found caused the pump to buzz.
This is not hard to believe, I'd imagine between the fuel and the heat the rubber wants to soften up and collapse.

[Bitsyncmaster]

I don't recall you talking about this before. Did you go with a heat exchange unit like Grady's tranny cooler or some sort of mini radiator? Where did you install it?

It was posted on the old forum. I made a heat exchanger around the AC accumulator. I think this will cure the buzz problem but it's not something most people would tackle doing.

[sean]

I remember now! What are your findings on the return temperature change this mod has caused?

[Bitsyncmaster]

I remember now! What are your findings on the return temperature change this mod has caused?

I had found without the cooler the return line would be 1.5 degrees F higher than the supply line. With the cooler it was quite a bit less but that was late in the year so my testing stopped. I have not done any trips this summer so the big test will be driving to DCS-12 next year.

[sean]

Got a hot air dam installed too? Be interesting to see your temperature ranges during your drive to Orlando plus what you start reading when you hit Florida in June, that will be a good test!

[Bitsyncmaster]

Got a hot air dam installed too? Be interesting to see your temperature ranges during your drive to Orlando plus what you start reading when you hit Florida in June, that will be a good test!

I do have Hervey's hot air dam. I wish I had done temp testing before and after but I really think 90% of the heat problem is return line and not heat picked up by the outside of the tank. The tank is a pretty good heat insulator, if it were a good heat conductor the bottom plate would keep it at air temperature.

[Ron]

Very interesting! Please keep us posted.

[sdg3205]

Dave, is that just copper piping?

Anything special other than what we can see?

[Bitsyncmaster]

Dave, is that just copper piping?

Anything special other than what we can see?

Yes it's just soft copper pipe for AC work that is sized so the hose fits tight. I think I used epoxy to hold it on and then some bondo for more strength at the ends.

[jorge figueroa]

you should use the same product used in the exhaust headers as 504150425043
cover the cooling tubes in the fuel tank area
controlling the transfer of heat between the cooling tubes and the gas tank
so the fuel pump is not affected by heat and the engine will have better performance
Heat is the horsepower and performance killer.


http://www.thermotec.com/products/11001-exhaust-insulating-header-wrap.html

[Bitsyncmaster]

Not a real long test but I had no fuel pump buzzing problems driving from Sanford to Orlando with less than a 1/2 tank.