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1996 Honda Civic and Vapor Lock

It has been high humidity and 90+ here in Chicagoland. We put our 1996 Honda Civic in the garage the other day. The garage turned into a steam room and now our car will not start. My other half thinks it is vapor lock. How do we resolve this problem?

Vapor lock is something different; it has to do with the gasoline vaporizing and not getting to your engine. The fuel system does not care about the humidity, but your IGNITION SYSTEM does. Your 13 year old car may have worn or cracked ignition wires and other components.

I would have the ignition system checked out first.

P.S. I lived in the tropics with 100% humidity and 95 degree temperatures, and vapor lock was never a problem.

Like Doc said, sounds like ignition. Vapor lock is very rare these days because of fuel injection. The gasoline is now under pressure, preventing the boiling that often occurred in hot weather with carburetors. I’m pretty sure your '96 has fuel injection, so forget about vapor lock.

Fuel injected cars don’t vapor lock.

The problem could be worn, dried out spark plug wires, as others have suggested.

It could also be that the engine is not getting fuel. The Main Fuel Pump Relay is located under the dashboard, and often causes starting difficulties in older Hondas when the temperature of the interior is high, such as when they’ve been parked in the sun.

Can you hear the fuel pump running when you turn the key to “ON?”

Yes, it sounds like it is getting gas, but it is not igniting the gas. It is so strange. The car only has 46,000 miles and it was working perfect 2 days ago before we put it in the garage and had a heat advisory.

We are planning on checking the wires and plugs tonight.

Try using a blow dryer ( the knid used for hair) to dry out the ignition system.

Vapor lock was a problem in older cars because the fuel pump was located on the engine. It would suck fuel from the tank, and the lower pressure from the suction would cause the fuel to vaporize in the line. The new fuel injected cars have an electric fuel pump located in the tank. It is submerged in the fuel, so there is no suction.

It’s difficult to say without knowing if the problem is fuel or spark related but vapor lock it is not likely to be.
Some potential causes could be a faulty main relay or ignition switch (both can be affected by heat and both are chronic problems) or even a moisture laden distributor cap.
Some Hondas were covered under an ignition switch Recall but I don’t remember offhand if the '96 Civic was or not. Non-covered models outside of the Recall range also suffer some of the same problems.
Recalls involve some politics and car makers try to keep the politics as confined as possible.

You might try popping the distributor cap loose to see if the inside is wet. If so, wipe the moisture out and then wipe the cap down with WD-40.
If no moisture is present then the next step is to determine what’s missing; fuel or spark.

You say “the garage turned into a steam room” - was it just hot and humid, or was there an actual water problem?

It was hot and humid. We did have the car out of the garage for a few days and it rained really heavy. But the care started fine to place it in the garage. There was no water in the garage. (we do not drive this car very much. It is or extra car)