difficulty starting car after engine warms up

[Aurora61]

After approx 30min of driving, my s15 has a really hard time starting. My car cranks when i turn the key, but the engine doesnt always start. Sometimes, the car will start while depressing the accelerator pedal, but most times will require a few tries.

I suspect its temperature related, especially since the car starts normally if i let it sit with the engine bay open for a couple of minutes. Also, my car starts immediately if the engine is cold. Once the car starts, i have no problems whatsoever until i turn it off.

Ive tried changing the coolant temperature sensor, but that had no effect. The problem is definitely not MAF related, because im running a MAF-less setup with a HKS Fcon V Pro ECU. Im able to hear the fuel pump after turning the key, so i dont think thats the culprit either.

Can someone point me in the right direction?

 

[Nickichi]

maybe its hot enough under the hood that it's vaporising the fuel within the pipework before the injector and creating a blockage.

 

[Aurora61]

maybe its hot enough under the hood that it's vaporising the fuel within the pipework before the injector and creating a blockage.

Thanks for the help, but unfortunately i dont think thats the issue. When i couldnt start the car, i primed the fuel pump a couple of times, so there was definitely fuel in the lines.

 

[spoonman]

have you looked though the S15 manual (.pdf) which is posted in the usefull threads it has a trouble shooting guide, there may be something in there

 

[Hypnotik]

I was having this same issue when it started getting warmer this summer. I had to open the injectors a few extra milliseconds during cranking via my Power FC and now it starts perfect everytime. It will be harder to do since you have the F-con, you'll probly have to take it back to whoever tuned it to have them fix it unless you have the software.

 

[Aurora61]

Yea, i was afraid it had to do with my tune. I had my car tuned in the winter, so i assumed that the difference in temp affected my starts. Unfortunately, re-tuning isnt cheap so i prefer not to go that route.

Is there something else i can do as an alternative, such as buy a better battery (optima yellowtop for example)? Im running a bunch of gauges and other miscellaneous electronics off of a tiny battery, so im thinking if i upgrade the battery, itll provide better start up as well as being able to properly support my electronics.