[Zabuden]

Hello all, I'm new to the forum, but I recently bought a used 2002 4.6L Mustang GT and I've been noticing a reoccurring issue. Whenever I try to restart the car after I have had it running and the engine is warm, the car will crank for a while and stumble to life, or slightly more rarely, the car will crank for a while and not start.

The battery was just replaced before I got the car and an electric test shows that the alternator and the battery are both fine.

This leads me to believe that it is probably a vapor lock problem. The car starts up quickly and solidly (no long cranks or sputtering) when cold, and I can hear the fuel pump click on when I turn the key to on. However, when the engine is warm the start suffers these symptoms and I have trouble hearing the fuel pump click at the on position.

Any advice/help for what to do about this would be appreciated, as well as whether vapor lock can be harmful to other parts of the car.

PS: I live in Florida so the only weather conditions that effect the car is heat. However, this problem will still happen in the morning before it even gets hot. The only noticeable indicator is whether the engine is warm or not.

Thanks!

 

[heavy metal]

Welcome to the site!!

 

[wmburns]

FYI vapor lock does not happen on a fuel injected car. Why? The nature of fuel injection doesn't allow it to occur and the PCM program "adjusts".

Try this. Cycle the key on/pause/off several times without cranking. Listen for the fuel pump to run each time. Does this improve starting? If so, consider fuel pressure leak down as a possible cause.

Hold the throttle half way open during cranking. Does this improve starting? If so, consider a bad IAC valve as a possible cause.

Confirm that the MAF is clean.

Confirm that the fuel pressure intake vacuum reference line is connected and leak free.

Confirm there aren't any vacuum leaks.

 

[Zabuden]

Thanks for the reply wmburns. As you can probably tell from my mistake, I'm not very knowledgeable on car maintenance.

I forgot to mention that my Mustang is an automatic. (Yes, I know...a GT automatic, lol). This may be a stupid question, but am I still able to hold the throttle halfway down in park with an automatic instead of a stick?

I talked to some of the guys at the shop and had him listen to the symptoms and he suggested that the fuel pump was not providing adequate fuel pressure upon starting, but I can still check into these other things.

Thanks