Hot start issue. Need to pick some brains. Any help appriciated.
 

Okay so here is the back story:

Car does not start when it has been running and becomes hot. It cranks and cranks and is so close to turning over but just doesn't have the juice. We ran a compression check and came back with numbers of: Front - 89,91,96. Rear - 96,91,95.

So far we have replaced the Fuel Pressure Reg, Air Control Valve, Air Pump, Starter Solenoid, and Starter. Also, i had a leaky injector, so we had it replaced, and had the remaining injectors repaired and cleaned.

There is satisfactory spark when the no-start occurs. The motor has been through deflooding procedures and still no start. vacuum appears to be fine.

The car only has a downpipe, new spark plug wires, and a pulley kit. Otherwise its stock.

Any advice, help, criticism, ideas... anything would be helpful.

I have actually had this exact problem before. It acts like it has vapor lock (carburetors get this). Do you have to wait till it cools down before you can start again? Or can you get it started after a lot of cranking?

I know I would press on my gas pedal repeatedly while cranking and that is how I got it to start again and once it was running rev it to high RPM's like 5,000 or so just to keep it running otherwise it would die again and I would have to go through the same process. This only happened to me when it was hot as well.

I have not had that problem since I changed over to a single turbo, but then again I haven't driven it enough during the winter to see if it really went away.

Changing your FPR seems like it would be the problem, provided the old one was bleeding off pressure, but as you said you have a new one so that is not it.

I wonder if there might be blockage in the fuel line feed/return from the fuel tank?

AIT sensor reading wrong temperature? That can cause hot-start problems.

We've tried cranking the motor while pumping the gas with no luck. But yes, you said it exactly how we do. Its almost like a vapor lock. We think that it its a fuel problem somewhere. We are just trying to figure out where to start. We'd have to check for clogs in the fuel lines.

have you replaced the plugs? your op says plug wires but not plugs.

Yes, sorry, it has fresh plugs in it as well.

on the vapor lock idea:

the fuel temperature sensor is supposed to switch the fuel pressure solenoid in order to prevent vapor lock.

Is that the same as the fuel thermo sensor? Im assuming it is. We are going to be replacing that once it comes in.

Anyone else? Going to start digging tomorrow.

why dont you do a fuel pressure test on idle and with key on? That can tell you if you are still having "bad leaky" injectors which can cause a fuel vapor lock and unable to start vehicle.


Like the other guy mention about the IAT (intake air temp) sensor, which can be bad an causing a faulty reading for the ECU to misinterpreted and unable to start the vehicle. Check the FSM for instruction regarding how to diagnosis the sensor.

-AzEKnightz

The injectors were rebuilt and are not leaking, that was our first assumption.

I do plan on checking the IAT sensor and the thermo sensor so far.

i have the same problem , if i shut it off while already warmed up and try to start it back up it wont , and then i get a strong fuel smell, i have replaced my fuel pump with a 255 walbro, and the t2 i have is bone stock anything ? im a complete newb to rx7 since i just got it

Did you guys find the problem for the hot starting, yet?