only starts well when cold

[windle27]

ok so one day i went to start my jeep after it had ran fine one hour ago (engine was still warm) and the check engine light came on and it wouldn't start unless i hit the gas. i turned the key over three times and found the coolent temp sensor was the issue so i replaced it and no change. my jeep starts in the morning just like it should but if the engine is warm it starts like crap and doesnt want to run for like the first five minutes.

can anyone help me any sugestions would be great this is my DD and i need to fix it

 

[JeepCherokeeGuy99]

please supply us with the year, model, tranmission, and engine size.

 

[JeepCherokeeGuy99]

is it overheating at all? almost sounds like when the thermostat is open it starts to run like crap.

 

[windle27]

its a 96 cherokee automatic with the 4.0

 

[birchlakeXJ]

So no more check engine light with the replacement of the coolant temp sensor?

 

[windle27]

nope i still have a check engine light

 

[orange]

The front temp sensor is for PCM only, the Instrument panel gauge sensor is at rear of head near firewall drivers side.

Be sure battery volts stay good, weak volts really mess up the electronics,

Get a scanner read of the codes for more info, see AZ or other auto parts stores. If lucky they can reset to see if its cleared.

Might unplug and replug in the connector on the CPS (crank) and check it for good wireing and snug fit.

Good Luck,
Orange

 

[windle27]

ok thank you

the more sugestions the better thax guys

 

[birchlakeXJ]

If the obd system is still coding for the coolant temp sensor, listen to it. It's pretty darn accurate on leading you down the right road of which subsystem to check. And your symptoms are consistent with a coolant temp sensor problem.

Just because you replaced the coolant temp "sensor", that doesn't mean that there can't be a problem in the coolant temp "circuit". The circuit is more than just the sensor.

That means inspecting both the connector and all associated wiring very closely. I like to use dielectric grease on all sensor connections. Connections/wiring is often overlooked. I can't remember when they switched to only one coolant temp sensor but I believe a 96 may only have one, located in the thermostat housing. Controls both gauge and input signals to the computer.

 

[JeepCherokeeGuy99]

If the obd system is still coding for the coolant temp sensor, listen to it. It's pretty darn accurate on leading you down the right road of which subsystem to check. And your symptoms are consistent with a coolant temp sensor problem.

Just because you replaced the coolant temp "sensor", that doesn't mean that there can't be a problem in the coolant temp "circuit". The circuit is more than just the sensor.

That means inspecting both the connector and all associated wiring very closely. I like to use dielectric grease on all sensor connections. Connections/wiring is often overlooked. I can't remember when they switched to only one coolant temp sensor but I believe a 96 may only have one, located in the thermostat housing. Controls both gauge and input signals to the computer.

if the code is still being thrown, and the circuit checks out ok, i would look at your water pump or thermostat. Are you overheating at all?

 

[Apostle]

never got a code, but same symptoms (sort of). check the plugs. mine started great when cold, but when warmed up there were issues. plugs had 1mm of center left.

 

[windle27]

if the code is still being thrown, and the circuit checks out ok, i would look at your water pump or thermostat. Are you overheating at all?

thats the other thing i forgot to say is that the electirc fan is on all the time.