Car turns off after it warms up

[jkim240]

Hey guys, i got my starter changed and everything starts right, but when i start my car after about 10-15 minutes, the car shuts off on its own. I can not start the car again after it has shut off by itself, and i have to wait till it is cold again to start it up. Does anyone know what the problem could be? possibly a sensor?

[s13 @ fullboost]

wait so your saying that your car starts and runs fine until the thermostat opens then it shuts off?

[Razi]

Check your ECU coolant temp sensor.
Maybe it's bad and the ECU thinks the car is overheating.

[s13 @ fullboost]

dont think the car has a safety future like that? even if coolant temp was reading hi temp the computer wouldn't shut off the car.

[jkim240]

yea thats what i was thinking because the car would probably just overheat instead of shutting off. it just turns off after the car runs for like 10-15 minutes, then it wont turn on again till its cold.

[jkim240]

anyone have any ideas?

[Tenchuu]

ghost. perform a Exorcism.

[lazysk8er2]

got any shorts in the car?

maybe heating up some wires by them touching a warm spot like a coolant hose?

do you have enough gas?

does it sputter and die out, or just powers down as if you used the keyto shut it off?

[jkim240]

yea theres enough gas and the car shuts off as if you would turn it off with the key.

[blueshark123]

Check your ECU coolant temp sensor.
Maybe it's bad and the ECU thinks the car is overheating.

Check that yet im sure its that. the one with 2 wires going into it not 1

[lazysk8er2]

^^^haha yea my friend said that used to happen but would blow his maf out tho. wierd. check your fuses too.

essentially its something electrical. maybe your ecu is getting too hot is it in a good place.

(you wont believe the hack jobs ive seen on some peoples car.)

[jkim240]

thanks for the replys, are there any other reasons why a car would turn off by itself when it gets warm?

[lazysk8er2]

try doing some diagnosing. so we can rule out some ideas. also what motor do you have? whats in your car? what kind of car is it? noone is reponding cuz u didnt give basic info.

if your not ambitious and trying to help yourself noone is gonna help you either.

[jkim240]

sorry bout that. I have a 1993 KA24DE, all stock, no modifications other than an exedy stage 1 clutch. All of the spark plugs and distributor wires are new. Oil and filter has been changed. The motor was put in the car recently, and as we went for a test run, the car started acting this way. Brand new starter, and all the fuses are good, and the battery is new too. Have not checked the ECU coolant temp sensor or if the ECU is getting hot. Will check tho, and yes theres basically a full tank of gas in the car. Thanks for everyones help.

[Howlermonkey]

Once the car is in failure, turn on the key and see if the check engine light comes on.

If so, I would start at the distributor since that is where about 90% of these kinds of problems occur.

In your case it would be the car losing crank position reference because materials within electronic modules can crack with age.

The difference in rate of expansion of said dissimilar materials will cause an open circuit at the crack as the component goes through a warm-up cycle.

You need to check for codes.

If there are no codes displayed, the check engine light does not come on when key on, or you cannot communicate with the proper scan tool, read below.

Since this issue came up at my job about 20 times a week regardless of car make, I would check the reference voltage supplied to a few of the sensors once the car is experiencing the failure.

If you find no reference voltage where you should, then you have a sensor that is subject to engine heat that is probably shorting the reference voltage to ground at a certain temperature.

Since the power supply within the ecu that supplies the reference voltage for sensors is divined from the same power supply that runs the ecu, then a shorted sensor can very well cause the ecu to do nothing at all or it can put into a state of crisis.

If you find zero voltage at any of the 3 wire (tps...etc) or more than 3 wire wire sensors (maf and distributor) then you next need to unplug them all and see if the reference voltage line comes up.

Many nissans use 12v supplied by a relay for distributor and receive no reference from ecu but you can find that out by looking at the testing protocol for it to see whether it is fed by the ecu or just fed battery voltage......same for some MAF sensors.

The big hint is that all 5v reference is supplied by the ecu.

It's up to you if you want to unplug all at once and check or one at a time while checking but, if voltage comes up when they are unplugged, you should be to easily find which one is shorted through the process of elimination.

If you have unpluged all reference voltage supplied sensors and still have no reference voltage, then it is another component within the engine compartment subject to engine heat.

It is highly unlikely it is the ecu itself unless another component failure as listed above has damaged it and then that ecu being failed would still be a secondary symptom of a shorted coil, IAC, or another component that is causing the ecu to fail when loaded excessively.

For me?

I unplug all of the sensors since it takes about 150 seconds to do so

The two wire sensors won't cause a car to stop running because they have a different type of reference voltage in that they are designed to resist the reference voltage to sensor ground so they cannot put the ecu into crisis if shorted to ground.

In normal operation, 2 wire sensors resist the Vref to ground or damn near fully shorted to ground anway.

They will just show the highest or lowest reading they can on the data list if they are shorted.

One thing to be aware of is that you could end up having the problem component "start working" from being handled or cooling while you are doing testing so you might have to test twice.

Needing a new starter was another symptom of this problem possibly because of excessive cranking.