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Random Stalling issue

FlexJ17

NAXJA Forum User
Just recently my 2001 jeep cherokee, (normally on the first start of the day) will start fine but as soon as i drive to the first redlight and sit for a minute, the rpms will increase slowly as if i was slowly pressing the gas and then i will go to accelerate and it goes a few feet then completely shuts off, then i'll try to crank and crank but it wont start, cranks fine, but no start. sometimes it wont start for 10 minutes sometimes 15, sometime it will start a minute after it dies, but each time with hesitation (i have to crank and give it good gas), then it will start up and drive fine. there always is the warning of the rpms raising first, thats how i know its gonna happen, and always at a stop.
 
i would also like to add, just yesterday i got a p0118 code for coolant temp sensor circuit 1 being too high, and a couple times the temp gauge just wouldnt work, im thinking maybe that could be the problem, im reading that a bad temp sensor could cause my problem
 
I'd start by replacing the ECT sensor. Almost all ECT sensors are a negative temperature coefficient type, meaning as the engine warms up, the resistance decreases, resulting in more voltage reaching the PCM. On a cold-start, the PCM just wants to dump fuel to the engine since less of it is going to vaporize (similar to an old-school choke.) The ECT sensor is also the only sensor the PCM pays attention to to make fuel adjustments when first started and as the engine warms up. So, in a nutshell-

Engine start-up/warmup: Lots of ECT sensor resistance, low voltage to the PCM, lots of fuel. (Open-loop engine mode.)

Engine warmed up: Less ECT sensor resistance, higher voltage to the PCM, less fuel. (Closed loop engine mode.)
 
Edit: Minor brain fart, it's possible (but I suspect highly unlikely) that the ECT sensor circuit is shorted to voltage somewhere. To verify this, disconnect the ECT sensor. Measure the voltage on both terminals of the connector with the key on. One should have voltage, the other should not.
 
thanks jeepnoob i will go ahead and test that with a multimeter, and also gonna go buy another temp sensor. embarrasing holding up traffic because my jeep randomly died and wont start lol
 
Yes, ECT= Engine Coolant Temperature.

Test with DVOM FIRST. Key on, if voltage on both wires, you're gonna have to start chasing a short to voltage. If one wire has 0 volts, and the other has ~5 volts, suspect a faulty ECT sensor.

And yeah, I know it can be a PITA. My '96 once had a problem where it would only stall at low engine speeds. Once it got running faster, the problem would go away. Long story short, I found my pickup coil in the distributor COATED in oil. How it got in, I haven't a clue, but I suspect centrifugal force from higher engine speeds was causing oil to sling off the pickup coil target and vice-versa. A new distributor and gasket fixed the problem..
 
If you have known fault or failure, fix that first. You cannot properly diagnose and trouble shoot problems when you have the potential of multiple causes for the symptoms.

Solve the P0118, and then see what happens. If the stalling persists, suspect the Crankshaft Position Sensor, the Idle Air Controller, and the Throttle Position Sensor and their wire plugs and wire harnesses. Test the sensors, check wire continuity of the wire harnesses, and inspect the wire plugs for corrosion, or pushed back/bent wire plug pins.


P0118 JEEP - Engine Coolant Temperature Sensor Circuit High

Possible causes
•Faulty Engine Coolant Temperature (ECT) sensor
•Faulty engine coolant thermostat
•Engine Coolant Temperature (ECT) sensor wire harness is open or shorted
•Engine Coolant Temperature (ECT) sensor electrical circuit poor connection
•Low engine coolant level
 
I vote for the crank sensor as well for the stalling. As they start to fail, the signal can get weaker as it warms up and the signal strength is also rpm dependent.
 
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