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intermittant elec. problem

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peanut
New User

Feb 23, 2008, 5:04 PM

Post #1 of 2 (1446 views)
post icon intermittant elec. problem Sign In
i recently gave my 97 plymouth grand voyager with a 3.3 a tune up and changed the upper plenom gasket. afterwards i drove the vehicle about 50 miles. after about 25 miles the vehicle started bucking intermittently before the tune-up it registered a ps402 engine code which is low flow in e.g.r. system. during the tune-up i disconnected the battery when complete the check engine lite never returned and currently there is no trouble codes stored but the intermittent problem still existes and one time it may take 15 min. to start next time i drive it it may take 45 min. to start. any ideas what the problem might be?


Double J
Veteran / Moderator
Double J profile image

Feb 25, 2008, 12:31 PM

Post #2 of 2 (1433 views)
Re: intermittant elec. problem Sign In
I assume it cranks over but won't start...

If so ,I'd be looking at possibly the crankshaft position sensor and/or the camshaft position sensor to be at fault...
Just a thought...

Here's a test to see....


NOTE: This no-start test checks the camshaft position sensor and crankshaft position sensor.

Theory of Operation
The Powertrain Control Module (PCM) supplies 8 volts to the camshaft position sensor and crankshaft position sensor through one circuit. If the 8 volt supply circuit shorts to ground, neither sensor will produce a signal (output voltage to the PCM).

When the ignition key is turned and left in the ON position. the PCM automatically energizes the Auto Shutdown (ASD) relay However, the controller de-energizes the relay within one second because it has not received a camshaft position sensor signal indicating engine rotation.

During cranking, the ASD relay will not energize until the PCM receives a camshaft position sensor signal. Secondly, the ASD relay remains energized only if the controller senses a crankshaft position sensor signal immediately after detecting the camshaft position sensor signal.

Test Procedure
  1. Check battery voltage. Voltage should be approximately 12.66 volts or higher to perform failure to start test.

Fig 18 Ignition Coil Electrical Connector

  1. Disconnect the harness connector from the coil pack (Fig. 18).

Fig 21 Ignition Coil Engine Harness Connector

  1. Connect a test light to the B+ (battery voltage) terminal of the coil electrical connector and ground as shown in (Fig. 21).
    • The B+ wire for the DIS coil is dark green with an orange tracer.
    • Do not spread the terminal with the test light probe.
  1. Turn the ignition key to the ON position.
    • The test light should flash ON and then OFF.
    • Do not turn the Key to OFF position, leave it in the ON position.
  1. If the test light flashes momentarily the PCM grounded the Auto Shutdown (ASD) relay Proceed to step 5.
  2. If the test light did not flash, the ASD relay did not energize.
    • The cause is either the relay or one of the relay circuits.
    • Use the DRB scan tool to test the ASD relay and circuits.
  1. Crank the engine.
    • If the key was placed in the OFF position after step 4, place the key in the ON position before cranking.
    • Wait for the test light to flash once, then crank the engine.)
  1. If the test light momentarily flashes during cranking, the PCM is not receiving a crankshaft position sensor signal.
    • Use the DRB scan tool to test the crankshaft position sensor and sensor circuits.

  1. If the test light did not flash during cranking, unplug the crankshaft position sensor connector.
  2. Turn the ignition key to the OFF position. Turn the key to the ON position, wait for the test light to momentarily flash once, then crank the engine.
    • If the test light momentarily flashes, the crankshaft position sensor is shorted and must be replaced.
    • If the light did not flash, the cause of the no-start is in either the crankshaft position sensor/camshaft position sensor 8 volt supply circuit or the camshaft position sensor output or ground circuits. Use the DRB scan tool to test the camshaft position sensor and the sensor circuits.



The Crankshaft Position Sensor is mounted on the transaxle bellhousing.








 
 
 






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