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brownjeff
brownjeff, ASE Certified Technician
Category: Jeep
Satisfied Customers: 13886
Experience:  17 years experience, ASE certified, dealership certified, Service Manager for 15 years,
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1987 jeep cherokee: 4.0...replaced ignition module and coil

Customer Question

I have a 1987 jeep cherokee with a 4.0. I have no spark. I have replaced ignition module and coil and still don't have spark. There is power to the positive side of the coil when the key is turned on. what else could be wrong?
Submitted: 7 years ago.
Category: Jeep
Expert:  brownjeff replied 7 years ago.
Has the cam sensor (pick up coil) inside the distributor been checked or replaced?
Customer: replied 7 years ago.
no. were is this located? Is it just under the cap and rotor?
Expert:  brownjeff replied 7 years ago.
Correct it is under the distributor rotor.
Customer: replied 7 years ago.
how do I check this and how do I remove it?
Expert:  brownjeff replied 7 years ago.

TEST

 

  • Connect positive lead of a suitable analog voltmeter to blue wire at distributor connector. Connect negative lead of voltmeter to gray/white wire at distributor connector. Do not disconnect distributor connector. Make voltmeter connections through back of electrical connector.
  • Place ignition swittch in the On position and note voltmeter reading. Voltmeter should indicate 5 volts.
  • If there is no voltage reading, check voltmeter leads for proper connection. If there is still no voltage reading, disconnect ECU electrical connector and check for voltage between connector terminal C-16 and ground. If there is still no voltage reading, check ECU with diagnostic tool M.S. 1700.
  • If voltage is present, check for continuity between blue wire at distributor connector and ECU connector terminal C-16. If continuity does not exist, repair wiring.
  • Check for continuity between gray/white wire at distributor connector and ECU connector terminal C-5. If continuity does not exist, repair wiring.
  • Check for continuity between black wire at distributor connector and ground. if continuity does not exist, repair wiring.
  • With analog voltmeter connected as described in step 1, crank engine. Voltmeter needle should fluctuate while engine is being cranked. If voltmeter does not fluctuate, replace stator located inside of distributor.
  •  

    REPLACE

     

    Fig. 6 Distributor stator assembly. 6-243 engines


    6-243 ENGINE

    STATOR, REPLACE

    1. Remove distributor .
    2. Remove rotor from distributor.
    3. Position distributor in a soft jawed vise to provide support for distributor gear removal.
    4. Using a small punch, drive distributor gear roll pin from distributor shaft and remove gear.
    5. Carefully remove distributor shaft from housing.
    6. Mark location of stator so that it may be installed in the same position, Fig. 6.
    7. Remove stator retaining screw and lift stator from distributor.
    8. Reverse procedure to install.
    Customer: replied 7 years ago.
    What is the ECU and were is it located?
    Expert:  brownjeff replied 7 years ago.

    Engine control unit (computer)

     

    Under RH Side Of I/P, Near Glove Compartment

    Customer: replied 7 years ago.
    Ok I did all tests. I have 6.93 volts and it fluxuates when you crank it over. I also have continuity to specs. whats next?
    Expert:  brownjeff replied 7 years ago.

    Check the crank sensor next:

     

    1. With engine at operating temperature, disconnect speed sensor electrical connector from ignition control module.
    2. Connect a suitable ohmmeter between connector terminals A and B, Fig. 8.
    3. Ohmmeter should indicate 125 to 275 ohms, if not replace sensor.
    Customer: replied 7 years ago.
    unsure on this test. Ignition module has two conections. one has one wire and the other three. your test does not match. were is the crank sensor and do I do this test with engine cold as it will not run?
    Expert:  brownjeff replied 7 years ago.
    Follow the pig tail of the sensor until you find the connector and disconnect it from there. There will be three connections on the connector but only two will have wires in them. You can still do the test cold as normally when it fails there will be no resistance at all
    Customer: replied 7 years ago.
    where is the sensor located?
    Expert:  brownjeff replied 7 years ago.
    Transmission bell housing on the passenger's side