Car Was Hot And Shut Off - Wouldn't Start...

[Bitsyncmaster]

So far I have not heard of any problems with the new pump/sender combo with hot fuel. No reports of the buzzing that the OEM pump would do. I've measured that fuel in the tank gets over 130 degrees F after a drive.

[kings1527]

My engine shutdown problem has been traced to a bad fuel pump. And the pump I had in there was the new pump/sender combo. However, here's where I think I went wrong and what I'd recommend for people living in hot(ter) climates:

1) It's been well documented that the hot fuel situation in our cars can reach 120+ degrees, thanks to testing by Dave M. The very likely culprit is fuel returning back to the tank via the return line and the original fuel pump setup would become symptomatic (loud fuel pump buzz, collapsing hose, stalling) when fuel capacity would be under 1/2 tank.

2) The new combo setup takes the hose out of the equation, but be careful. The fuel temp doesn't change.

3) Electric fuel pumps rely on fuel to keep it on the cooler side and for lubrication. If you keep sending hot fuel back to it, it will cause premature wear. Not only in our cars but in other cars, too. This is the most common cause of fuel pump failure, from what I've read.

4) I've had a habit over the past two years of only filling my car up when the low fuel light comes on or when it gets close to it. By this time in Southern Calif, the fuel pump has been taking a beating with hot fuel.

5) As electronics heat up and become worn out, they draw more amperage. Once the pump had been damaged to a certain point, as it would heat up the electrical demands of the pump would exceed the car's ability and the result would be the pump shutting down. It would start back up after the pump had time to cool off. (I'm about 75% certain with this point)

6) As time went on, the car would become symptomatic faster and with less heat.

So, the solution? I'd recommend making it a habit to fill up at a half tank particularly if you live in a hot area. I think that'll preserve the pump a lot better by keeping the fuel on the cooler side. After installing a new unit, I drove it around with the AC on the entire time and an engine temp of about 200 degrees for an hour and there wasn't even the slightest bit of a problem.

[Bitsyncmaster]

All else being equal, the copper wire in the fuel pump resistance would increase (a little) as it heats. That would result in less current driven with a constant voltage. But if the load on the pump increases due to bearings, less lubrication (the hot fuel) the current will go up.

[David T]

My engine shutdown problem has been traced to a bad fuel pump. And the pump I had in there was the new pump/sender combo. However, here's where I think I went wrong and what I'd recommend for people living in hot(ter) climates:

1) It's been well documented that the hot fuel situation in our cars can reach 120+ degrees, thanks to testing by Dave M. The very likely culprit is fuel returning back to the tank via the return line and the original fuel pump setup would become symptomatic (loud fuel pump buzz, collapsing hose, stalling) when fuel capacity would be under 1/2 tank.

2) The new combo setup takes the hose out of the equation, but be careful. The fuel temp doesn't change.

3) Electric fuel pumps rely on fuel to keep it on the cooler side and for lubrication. If you keep sending hot fuel back to it, it will cause premature wear. Not only in our cars but in other cars, too. This is the most common cause of fuel pump failure, from what I've read.

4) I've had a habit over the past two years of only filling my car up when the low fuel light comes on or when it gets close to it. By this time in Southern Calif, the fuel pump has been taking a beating with hot fuel.

5) As electronics heat up and become worn out, they draw more amperage. Once the pump had been damaged to a certain point, as it would heat up the electrical demands of the pump would exceed the car's ability and the result would be the pump shutting down. It would start back up after the pump had time to cool off. (I'm about 75% certain with this point)

6) As time went on, the car would become symptomatic faster and with less heat.

So, the solution? I'd recommend making it a habit to fill up at a half tank particularly if you live in a hot area. I think that'll preserve the pump a lot better by keeping the fuel on the cooler side. After installing a new unit, I drove it around with the AC on the entire time and an engine temp of about 200 degrees for an hour and there wasn't even the slightest bit of a problem.

There is no circuit breaker (or equivalent) that would shut off the pump and after cooling restart the pump so I disagree with #5. The main source of heat is the 2 cooling system pipes going to and from the radiator so I disagree with #1. One thing you could do (other's have done this) is to create a small heat exchanger by wrapping a coil of copper tubing around the A/C accumulator and passing fuel through it. Another thing is to add an air dam behind the radiator so the air from the cooling fans is deflected downwards and away from the fuel tank. The OEM set-up can work well but I would add a spring inside the pick-up hose so it can't soften up and collapse or kink. A collapsed hose is the worst of all cases since now the pump is getting NO lubrication and of course the motor can't run. I can't comment on the new pump set-up from DMCH since I don't have much experience with it. Yes, the problem tends to be worse the lower the fuel level and less mass of fuel that can absorb heat. More fuel also provides a head so the pump doesn't work as hard. It also gives you more range so all around it is the easiest solution.