Car starts and runs but shuts off

Tiny
ASHLEY053090AD
  • MEMBER
  • 1998 JEEP GRAND CHEROKEE
  • 4.0L
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 187,000 MILES
Car starts up runs for a few minutes and shuts off. I have replaced MAP sensor. I have replaced throttle position sensor. I have just installed new plugs and wires and a new converter. My battery is checked out to be fine and it has a new alternator. So what should I check for next? I am hearing a weird sound coming from the air hose connected to the air filter as well. It will shutter and shut off.
Thursday, August 16th, 2018 AT 3:26 PM

1 Reply

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,747 POSTS
Hi and thanks for using 2CarPros.com.

As far as the sound you hear, make sure there is nothing blocking the air inlet tube as well as make sure there are no major vacuum leaks. If unmetered air is getting into the system, it will cause problems.

Also, check fuel pump pressure to confirm it is not dropping off when it shuts off. Here is a link that shows how it is done:

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

The specific fuel pressure for your vehicle is: Engine at curb idle (49.2 ± 5 psi)

Also, a bad crankshaft position sensor can do this. If it is failing, you will lose spark. Read through these links.

https://www.2carpros.com/articles/symptoms-of-a-bad-crankshaft-sensor

General directions for replacing the sensor:

https://www.2carpros.com/articles/crankshaft-angle-sensor-replacement

Here are the directions specific to your vehicle for replacing the crankshaft sensor. The attached picture shows its location.

_________________________________________

The crankshaft position sensor is mounted to the transmission bell housing at the left/rear side of the engine block. The sensor is adjustable and is attached with one bolt. A wire shield/router is attached to the sensor.

REMOVAL
1. Disconnect sensor pigtail harness (3-way connector) from main engine wiring harness. This connection is made near rear of distributor.
2. Remove sensor mounting bolt.
3. Remove wire shield and sensor.

INSTALLATION
With automatic transmission: New replacement sensors will be equipped with a paper spacer glued to bottom of sensor. If installing (returning) a used sensor to vehicle, a new paper spacer must be installed to bottom of sensor. This spacer will be ground off the first time engine is started. If spacer is not used, sensor will be broken the first time engine is started.
1. New Sensors: Be sure paper spacer is installed to bottom of sensor. If not, obtain spacer PN05252229.
2. Used Sensors: Clean bottom of sensor and install spacer PN05252229.
3. Install sensor into transmission bellhousing hole.
4. Position sensor wire shield to sensor.
5. Push sensor against flywheel/drive plate. With sensor pushed against flywheel/drive plate, tighten mounting bolt to 7 N.m (60 in. lbs.) torque.
6. Route sensor wiring harness into wire shield.
7. Connect sensor pigtail harness electrical connector to main wiring harness.

_______________________________________

Let me know if this helps or if you have other questions.

Take care,
Joe
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Friday, August 17th, 2018 AT 6:53 PM

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