Car starts when cold, wont start after being fully warmed up. wtf?

[mikey060]

as the title states, my 180sx will only start when the engine is cold. it starts perfectly too. doesnt hesitate at all. however after i drive it enough to let it fully warm up and then i shut it off, it will not start up again. it will crank but will not start up. once i let it sit for 3-4 hours too fully cool down it will start up perfectly again. it is very consistant and hasnt once not failed to not start after warmup. any ideas what this could be? the car is basically stock, i have changed the air filter, fuel pump and it has aftermarket exhaust/downpipe. please help give me some idea what it could be. i will be taking the car to nissan but if there are some little things i can try i would like to atleast try them. thanks

[SleeperSx]

is the car getting too much fuel when trying to start? Have you tried pulling the fuel pump fuse and try starting it when its hot?

[Sileighty_85]

Coolant Temp Sensor

Mine did the same thing when I replaced my Valve cover gasket, I accidentily pulled the CTS off and would not start when warm unless WOT and cranked for 10 sec.
Reconnected it and it starts with no problems

Pull codes from the ECU to narrow it down

EDIT: If it is a CTS or another Sensor and your ECU throws a code for it dont forget to Reset the ECU

[makulit054]

I agree with sileighty 85. There was a thread about this not too long ago.

[apex]

^^ yup cts mine did the same shit

[g6civcx]

As an alternative, check relays. This problem is common on older Hondas where the fuel pump relay doesn't work when the cabin gets hot.

[mikey060]

Coolant Temp Sensor

Mine did the same thing when I replaced my Valve cover gasket, I accidentily pulled the CTS off and would not start when warm unless WOT and cranked for 10 sec.
Reconnected it and it starts with no problems

Pull codes from the ECU to narrow it down

EDIT: If it is a CTS or another Sensor and your ECU throws a code for it dont forget to Reset the ECU

that is the problem, i tired starting it with wot and cranked it for about 15seconds..starts fine now
i will be swapping my turbo soon and will be having it re tunned after i do so...when they re tune it will that reset it?

thanks alot for your response...saved me a lot of headache and money :bigok:

[mikey060]

alright so i ran the ecu and got the code 13. apperently that is indeed the coolant temp sensor circuit. so what exactly do i do know...does that just tell me it IS unplugged....or it is plugged in but something is wrong with it?

[Sileighty_85]

its either unplugged or bad

if its plugged in, then you need a new one.

Autozone 21"ish" bucks for a KA or 94 Sentra SER

the sensor is located above the thermostat housing you will see two sensors
it will the the left sensor square plug with two terminals inside

be prepared to catch coolant when you remove the sensor

after the new sensor is installed reset the ecu and you should be good

[mikey060]

alright thanks. i found it hid in some little spot next to the engine not plugged in. i plugged it back in and its all good now. thanks a lot for the help :)