If your car is new and not broken in, you need to carefully break it in, it's important.
If it starts and dies, first check that the battery is fully charged, if it is, try swapping for a new spark plug. Get 2 extras right away if you have none.
If the car runs for a while with a new spark plug, and you then end up with the same behavior. Swap back to the first one and try again.
Do not run the car much more than idle speed, or the speed needed to keep it running, not more than half throttle though, until the car is running fine and not dying every now and then. It might take 2-3 tanks (or even more). During this time, you'll be frustrated with the car stopping all the time. Just keep swapping between the spark plugs and keep it going. During these first 2-3 tanks, just take off the wheels, put the car on a stand, and let it run. When it runs fine for a whole tank, take it out and run it on the street for a tank or two to make sure it is running fine. Adjust the "throttle pusher" on the servo linkage so that full speed on your transmitter whil give only half throttle on the carburettor, just to make sure not pushing the car until fully broken in. After 1-2 more tanks, your car should be running fine and now, not before now, you can start fiddling with engine and gearbox tuning. Run stock settings for the whole break-in period. Do not run high rpm's during break in.
If the car is still not running ok after 4-5 tanks with the above procedure, or even worse. Take it back to the store and require they swap the piston, sleeve and piston ring. Simpy because, in my opinion, HPI has a compression issue as a result of poor manufacturing specs with these engines. Some will just never "break in" properly and give the compression required.
I tried and tried and tried everything trying to get mine to run, in the end I realised the pull started was way to easy to pull, which indicated no compression, so I got the tools and measured in, there was no compression. HPI refused to help out or replace the parts needed, so I had to by new ones my self. I have since gone through the process mentioned above, finalizing it today, my kids just ran the 6th tank earlier this evening, and the car ran from first start until empty tank without one single stop. Oh, it was raining outside and the batterybox had some water in it. Ballons may be a good idea 😉
I did have the problems and frustration mentioned. Be careful, keep stock settings, use charged batteries and keep swapping between 2 or 3 spark plugs, and you should be fine in the end. 🙂
