Mr. Kilmer, First of all I just wanted to thank you for all your videos. I started working on cars…
First of all I just wanted to thank you for all your videos. I started working on cars before I had a license, but have definitely picked up quite a few tips and tricks from your Youtube channel.
I noticed that many of your videos feature mid-90's Toyotas with the 4-cylinder 5SFE engine, so I'm guessing you've run into this issue before. I own a 1994 Camry that just hit 100k miles. It's in great condition, and the only problem I've ever had with it is a hot-start issue. This generally only happens if I've either (a) been driving the car for 2+ hours straight and pull over at a rest stop, or (b) I've made multiple short trips back to back. In both of these scenarios, when I start the car, it runs for about a second and then immediately dies. However, if I keep my foot on the gas and either hold the engine around 2000 RPMs for 10-20 seconds, or rev it to around 4000 RPMs once or twice, the car will run completely normally.
The car has been in my family for quite a while, and this problem has been happening for several years. In the past, it happened so infrequently that it wasn't really something worth throwing time and money at. However, it has recently begun to happen a lot more frequently.
New (or relatively new) parts include: air filter, spark plugs and wires, distributor cap and rotor, PCV valve, valve cover gasket, and timing belt.
It almost sounds like vapor lock in the fuel system, but my understanding is that this would be pretty unlikely in a modern fuel-injected car, and also would most likely take longer than a few seconds to resolve itself. My next thought was that there could be either a vacuum leak or a defective check valve in the EVAP system.
Is it possible that a valve is sticking open between the charcoal canister and the engine's air intake, and when the hot engine is turned off, some kind of residual pressure is forcing fuel vapor or even raw gasoline into the intake and flooding the engine? This would make sense to me because revving the engine would theoretically clear the excess fuel out.
The thing that throws me off is that it only happens in such specific circumstances. It seems like this problem would cause constant issues with the car (i.e. rough idle, running extremely rich, fuel odor, etc.).