cold engine starts up fine, but after running to the store and the engine is warm restart is a no go have to wait for it to cool and it will restart also a check eng. codes P01492 and P0172, any help out there?
No restart
- Thread starter Shooter878
- Start date
You are driving a 1999 4.0L A/T according to your profile.
Check to see if the coil windings are open due to heat.
Verify the fuel pump can be heard running for 3-5 seconds when the ignition is turned to Start.
Shift transmission to N and retry starting.
Check to see if the coil windings are open due to heat.
Verify the fuel pump can be heard running for 3-5 seconds when the ignition is turned to Start.
Shift transmission to N and retry starting.
Crank no start or doesn't crank?
Also check your battery terminals, voltage at rest and voltage while cranking.
-Mac
Also check your battery terminals, voltage at rest and voltage while cranking.
-Mac
checked the coil 5 crack around . res.test (coil out and cold) 12.43 sec. 1.4 prim. could be breaking down under heat. going to test CPS, MAP sensor .Anymore help will be appreciated. kind of leaning to coil. P0172 got alot of thing to try to check.
Factory Service Manual 8D-20 Ignition System; coil resistance for your year TJ 4.0L.
Dex sprays water on the crank sensor (he has a vid)and it cools it down and starts right up.now finding an acceptable aftermarket cps.
changed the coil, CPS was replaced DEC. 2025, testing is confusing, I know it it could a CPS heat problem, can you bench test with a multimeter an a heat gun?
and is so what readings would i get. Also someone said to check the temp. sending unit, anything with that idea and what would that cause, gauge reads just under 210.
and is so what readings would i get. Also someone said to check the temp. sending unit, anything with that idea and what would that cause, gauge reads just under 210.
Assuming CPS means CranK Position (CKP) sensor and not CaM Position (CMP) sensor, then yes it can be tested. The bracketed acronyms are what is used in the FSMs and avoids confusion.
This is described only in the 97 FSM I think but should be good for a 99.
To test the CKP sensor, an ohm-meter should be connected between the sensor ground and sensor signal terminals of the sensor connector. I don't know what colours the wires on your sensor will be but the wires on the loom side connector should be brown/yellow (sensor ground) and grey/black (sensor signal. The FSM states to use a meter on the 10K scale, and that the meter should read open circuit, and to replace the sensor if the meter indicates low resistance (without actually specifying how low that is).
If heating the sensor the resistance drops below 10K when heated I would presume the sensor is faulty. Having said that, I can't be sure how much the resistance would change with temperature.
The CMP sensor test is to backprobe the sensor connector and check for voltage. With the distributor cap removed the engine should be cranked the engine by hand so the rotor arm is at 11 o'clock when looked at from the side of the engine. Between the sensor ground (brown/yellow) and sensor signal (tan/yellow) wires there should be 5V shown with the ignition on. When the engine is cranked the voltage should alternate between 5V and 0V.
This is described only in the 97 FSM I think but should be good for a 99.
To test the CKP sensor, an ohm-meter should be connected between the sensor ground and sensor signal terminals of the sensor connector. I don't know what colours the wires on your sensor will be but the wires on the loom side connector should be brown/yellow (sensor ground) and grey/black (sensor signal. The FSM states to use a meter on the 10K scale, and that the meter should read open circuit, and to replace the sensor if the meter indicates low resistance (without actually specifying how low that is).
If heating the sensor the resistance drops below 10K when heated I would presume the sensor is faulty. Having said that, I can't be sure how much the resistance would change with temperature.
The CMP sensor test is to backprobe the sensor connector and check for voltage. With the distributor cap removed the engine should be cranked the engine by hand so the rotor arm is at 11 o'clock when looked at from the side of the engine. Between the sensor ground (brown/yellow) and sensor signal (tan/yellow) wires there should be 5V shown with the ignition on. When the engine is cranked the voltage should alternate between 5V and 0V.
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