purplexenno

my daughter is going to chicago this week and her stalling problems are back. She has a 96 jeep grand cherokee 4.0 that likes to stall out. At first it just quit and i replaced the crankshaft sensor, which only helped for awhile. So i got a manual and i know i need to replace the coil. However she gave me more info this time around (which would have been nice the first time) it seems the jeep surges before it stalls, and it gets hot and the heater doen't get hot anymore. Anyone who can help out here i would be very grateful.

Bustedback

It sounds like she is overheating the engine until it finally quits running. No heat means no water in the cooling system.

purplexenno

i should clarify, the heating occured after the second time it quit. I was thinking maybe the camshaft sensor was causing problems and that was making it run hot, of course i'm going to replace the thermostat but she lost heat for the heater in the middle of the winter, and here in NY that's bad.

Bustedback

A bad cam sensor won't make it run hot, but it can cause the engine to stall.

purplexenno

what would you suggest if i get the temp situation fixed and it still does it? i know there is enough pressure at the rail, and fuel filter is new (that was a mid winter repair where we got a lovely blizzard and 2 degree weather while i was working on it outside on a tarp in my drive way, that sucked). Since the heater blows but doesn't get hot i'm going to assume it needs a flush and fill, and hope there is no blockage. I really don't want to remove the distributer anyway (i have t4 to l5 spinal fusion and bending over the car all day does not sound fun, by the way that is about 3/4 of my spine). at this point i have a friend who have a analog multimeter (the manual says not to us a digital) so i'm going to check voltages this afternoon.

Bustedback

A thermostat that is stuck open will cause low heat output, and could cause the engine to run too rich. Is the check engine light on?

ol"blue

A blend door problem in the HVAC housing will also cause a low heat output from the heater.
And as Bustedback stated above a bad cam sensor can cause the random stalling issues. Try checking that top & bottom, and the rotor and cap for arching/carbon deposits. Also check its connector for corrosion/loose or cracked wires, and if needed apply some dielectric grease before reconnecting.
Test the cam Sensor.
CAMSHAFT POSITION SENSOR
The camshaft position sensor is located in the distributor
(Fig. 13) on all engines.
To perform a complete test of this sensor and its
circuitry, refer to the appropriate Powertrain Diagnostics
Procedures service manual. To test the sensor
only, refer to the following:
For this test, an analog (non-digital) voltmeter
is needed. Do not remove the distributor connector
from the distributor. Using small paper clips,
insert them into the backside of the distributor wire
harness connector to make contact with the terminals.
Be sure that the connector is not damaged
when inserting the paper clips. Attach voltmeter
leads to these paper clips.
(1) Connect the positive (+) voltmeter lead into the
sensor output wire. This is at done the distributor
wire harness connector. For wire identification, refer
to Group 8W, Wiring Diagrams(2) Connect the negative (-) voltmeter lead into the
ground wire. For wire identification, refer to Group
8W, Wiring Diagrams.
(3) Set the voltmeter to the 15 Volt DC scale.
(4) 5.2L/5.9L Engines: Remove distributor cap
from distributor (two screws). Rotate (crank) the
engine until the distributor rotor is pointed towards
the rear of vehicle. The movable pulse ring should
now be within the sensor pickup.
(5) 4.0L Engine: Remove distributor cap from
distributor (two screws). Rotate (crank) the engine
until the distributor rotor is pointed to approximately
the 11 o’clock position. The movable pulse ring
should now be within the sensor pickup.
(6) Turn ignition key to ON position. Voltmeter
should read approximately 5.0 volts.
(7) If voltage is not present, check the voltmeter
leads for a good connection.
(8) If voltage is still not present, check for voltage
at the supply wire. For wire identification, refer to
Group 8W, Wiring Diagrams.
(9) If 5 volts is not present at supply wire, check
for voltage at PCM 32-way connector (cavity A-17).
Refer to Group 8W, Wiring for location of connector/
terminal. Leave the PCM connector connected for
this test.
(10) If voltage is still not present, perform vehicle
test using the DRB scan tool.
(11) If voltage is present at cavity A-17, but not at
the supply wire:
(a) Check continuity between the supply wire.
This is checked between the distributor connector
and cavity A-17 at the PCM. If continuity is not
present, repair the harness as necessary.
(b) Check for continuity between the camshaft
position sensor output wire and cavity A-18 at the
PCM. If continuity is not present, repair the harness
as necessary.
(c) Check for continuity between the ground circuit
wire at the distributor connector and ground.
If continuity is not present, repair the harness as
necessary.
(12) While observing the voltmeter, crank the
engine with ignition switch. The voltmeter needle
should fluctuate between 0 and 5 volts while the
engine is cranking. This verifies that the camshaft
position sensor in the distributor is operating properly
and a sync pulse signal is being generated.
If sync pulse signal is not present, replacement of
the camshaft position sensor is necessary.