Vapor lock on a hot day

[Jaquon Jackson]

Hi Eric, I have a 2000 honda accord v6 and I keep experiencing vapor lock only on hot days. It seems as if the motor isn’t getting any fuel to it. I have to floor the pedal down while im cranking it at the same time in order for it to come on. I tried wrapping the fuel lines in cooling tape to see if that may do the trick, but no luck 🙁 Any suggestions?

Topic

[Mike]

On hot days, does it start OK during the first start of the day, or is it difficult only when restarting a hot engine?

[Jaquon Jackson]

yes it starts ok on the first start of the day, and it is difficult restarting on a hot day . I have 2 engine codes: P0131 (HO2s- 11 Bank 1 Sensor 1 Circuit Low Input) and P0401 (EGR System Insufficient Flow Detected)

[Mike]

Codes aside, it’s kinda unusual for a fuel injected engine to vapor lock. In the old days, when dinosaurs ran on carburetors, vapor locking was more common. Fuel pumps put out very low pressure, about 7 or 8 psi, so it was easier for the fuel in the line to expand and vaporize. Today’s fuel injected systems run at much higher pressures, making vapor lock a lot less likely.

If you are really experiencing vapor lock, I can think of three conditions that would contribute to it. (All of them are just guesses.)

1: Perhaps your fuel pump isn’t producing enough fuel pressure.
2: Perhaps your fuel system is leaking built-up pressure after the engine is shut down, allowing the depressurized fuel to vaporize.
3: Perhaps your cooling fans aren’t activating after the engine is shut down, causing the components under the hood to suffer from “heat soak” after the hot engine is off.

If your car has no driveability/performance issues, I’d feel safe to eliminate cause #1.

[Billy]

You seem to be jumping to a diagnosis based on intuition and ignoring the problems that the car is actually reporting. How about fixing what you know is broken? Verify the cause of the O2 sensor code and fix that, then deal with the EGR problem (sounds like the notorious blocked passages).

[edwin]

i’m with evil on this one, if the air/fuel mixture is off, ie; vaporlock then the O2 sensor will give you an error code even if the O2 sensor is still good.

in the old days vapor lock was caused by higher than usual under hood temperatures. cures were wrapping the fuel line like you already did and wrapping the hedders on modified cars.

[Author]

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