It's hot here as alot of places I know. Recently, I had changed my fuel pump,filter, and strainer when the car died on me and acted as if no fuel. It got me running again. I later had a problem again and found out it was a bad injector shutting down one side altogether. 1st thing in the mornings and the first few starts during the day/afternoon it does fine. Only after alot of idleing or driving around in the heat of the day, it'll die and will not restart for more than a few seconds until it sits for a hour, two, or more depending on how hot it is outside. I've unplugged the injectors 1 at a time to see if it's maybe a bad one again with no luck. The only thing that has gotten it restarted is if I put a few gallons or more of cool gas into the tank. The last time it died I had just filled the tank after it sputtered when hot, drove across town through several red lights, then let it idle for 10mins. It died and trying to cool the tank off with fresh fuel would have been futile.
What causes it to die when the fuel gets so hot?? I love the car, but it is a real inconveinance when you can't depend on it.

 

Is fuel presure consistent hot & cold?

Cooling system operating correctly-- engine temp normal when the car dies?

 

Engine temps are normal/cooling system working normally. Fuel pump does whine when it dies like it's starving for fuel. Don't have a fuel pressure gauge that I can leave on it. When I have checked FP, it's been 45-47lbs and doesn't bleed off when shut off for quite some time.

 

Having same problem I think, mine cuts out about 45 mins, let is set 2-3 hours and you're good to go another 30 minutes

 

Sounds like maybe the Ignition Control Midule in the distributor. They go bad from heat easily, and unless you know it's been changed out, probably never has been.

Fuel pumps are like 10 year old children - they always whine - like a 10 year old, if it doesn't whine THEN your in trouble.

 

What year and motor do you have? My 1986 Trans-Am has a 305 4bbl. It came from the factory with a little blower (under the battery) that has a hose connected to it that blows cool air directly on the carb +fuel line. It comes on when you shut the car off. I think it comes on if the temp is at 220 degrees. It will run for usually 45 min. or until you start it up again. Pretty sure this is to keep it from vapor locking??

 

Mine is a TPI 350. No blower for the motor other than the cooling fans behind the radiator. Have already changed the ignition module about 3 weeks ago. The ignition module would make the fuel pump sound differently when the car gets hot I don't think. A few gallons of cooler fuel ALWAYS gets it running. Definitly a fuel/heat issue I think.

 

I changed pumps 3-4 times to get one that would hold up.. I also have a trans cooler for a fuel cooler piped in the system to cool fuel in the tank down and the pump.

 

Buddy of mine went through 3 pumps as well to get one that would stand up. We would check the pressure and it would be good, but then when the issues would happen, pressure dropped and we replaced and bang, no more issues, also check the resistance of the injector coils, but measuring the resistance of the injector across the two prongs on the injector with it unplugged. should be over 12 ohms I think... Below is bad injector. these cars have poor stock injectors that commonly need replacing.

Hope this helps.

 

I have an LS2 with 60lbs injectors..

 

Although gasoline vaporizes at room temperature most of the tank volume is liquid fuel and the fuel pump inlet is completely submerged.
Unless you consistently run around in scorching temperatures with less than 1/4 tank of gasoline, vapor-lock shouldn't be a problem.
I would sugest a volume flow test when it's not starting.

 

The pump is knowingly below fuel level even at 1/2 tank when it happens. You can hear the pump sound like it cavitates or whines with a much more distinctive sound.

 

If it is cavitation it won't last very long. Cavitation will not only damage the fuel pump it will also damage fuel injectors.

 

I have the exact same problem. I use a high volume Walbro pump since I have a 383 and the stock pump wasn't enough. My theory is since the high volume fuel pump will pump so much hot fuel back to the tank at low loads, like city driving or freeway cruising, and the fuel return is right next to the pump, the pump is cavitating. I think I'm right because I use my car on race tracks and at full throttle use, I never have any problems because I'm using so much fuel, very little is returned to the tank. Also, if I'm on the freeway and I think the cavitation is starting (it will give me a lean pop and I can hear pump really whining), I drop it into a lower gear and run it at higher revs and harder throttle, and it doesn't stall. I'm going to drop the fuel tank and fabricate a fuel return line that returns the fuel away from the pump into another part of the tank. If this works, I'll know my theory was correct.

 

See my notes in reply number 14.

 

I am having this issue as well on my recently purchased 91 z28. Initially thought it was the ignition module, my fuel pump, especially in these hot temperatures was the culprit, I had my fuel lines replaced with stainless and awaiting to see the results.

 

Do these lines dissipate heat better or are they a larger diameter so less heat is generated by the fuel flowing thru them? If my idea of redirecting the return in the tank doesn't work, I was thinking of going to larger, insulated fuel lines. I have a 3 1/2" exhaust and I thought that might be adding heat to the lines also.

 

Do you have pictures of your set up

 

theres a tank vent valve by the rear axle on the left . when they get clogged, they can cause this symptom.

 

I never changed the return line. I went with a Bosch 044 fuel pump which flows a little less fuel than the Walbros but flows enough to support my 383 with 410 HP at the wheels. So I now have less hot fuel pumped back into the tank and I also insulated the exhaust (where it is close to the gas tank) and muffler by wrapping it with exhaust heat blocking wrap and and I glued heat blocking tape to the heat shield between the muffler and gas tank. Since I did this, no problems at all and it can get over 105 degrees at timess around here.

 

I have a 6.4L, but my SLP headers feed the factory exhaust single pipe Cat on the passenger side, and the fuel lines run along the driver's side of the tunnel. Both of my supply & return lines are 3/8" 316ss tubing. all the way to the stock fuel regulator modified with an adjustable regulator. I have never experienced vapor lock.