93 grand cherokee help

  • a good friend of mine has a 93 grand cherokee with the 4.0 litre engine and is having starting/running problems. he mentioned a while back the speedometer would work some days and not others...now it wont start.


    we sprayed the throttle body and it will start so it seems it is getting no fuel


    we checked the pressure in the fuel rail and it is getting proper pressure, and will re-pressurize when he turns the key so we feel the pump is working, filter is not clogged.


    im thinking ECM. what do you guys think?


    if it was one injector, wouldnt it just miss? misfire on a cylinder? none are firing.



    would the ECM out of a 93 wrangler work to help troubleshoot?



    any ideas? let me know
    thanks

  • Is it throwing any codes?



    OBDI Code List for Jeep YJ/XJ 1991-1995 (perhaps a 93 ZJ as well?)
    Turn key on/off three times, then on (engine not running), engine light will flash codes. Longer pauses are breaks between codes. Last code will be 55. Ignore code 33 on non ac


    11 No ignition reference signal detected during cranking OR timing belt skipped one or more teeth; OR loss of either camshaft or crankshaft position sensor.
    12 Battery or computer recently disconnected
    13 MAP sensor or vacuum line may not be working
    14 MAP sensor voltage below .16V or over 4.96V
    15 No speed/distance sensor signal
    16 Loss of battery voltage detected with engine running
    17 Engine stays cool too long (bad thermostat or coolant sensor?)
    OR
    17 (1985 turbo only): knock sensor circuit
    21 Oxygen sensor signal doesn't change (stays at 4.3-4.5V). Probably bad oxygen sensor
    22 Coolant sensor signal out of range - May have been disconnected to set timing
    23 Incoming air temperature sensor may be bad
    24 Throttle position sensor over 4.96V
    25 Automatic Idle Speed (AIS) motor driver circuit shorted or target idle not reached
    26 Peak injector circuit voltage has not been reached (need to check computer signals, voltage reg, injectors)
    27 Injector circuit isn't switching when it's told to (TBI)
    OR (MPI) injector circuit #1 not switching right
    OR (turbo) injector circuit #2 not switching right
    OR (all 1990-) injector output driver not responding
    - check computer, connections
    31 Bad evaporator purge solenoid circuit or driver
    32 (1984 only) power loss/limited lamp or circuit
    OR
    32 EGR gases not working (1988) - check vacuum, valve
    OR
    32 (1990-92) computer didn't see change in air/'fuel ratio when EGR activated - check valve, vacuum lines, and EGR electrical
    33 Air conditioning clutch relay circuit open or shorted (may be in the wide-open-throttle cutoff circuit or normal on early 80's models if you don't have air conditioning)
    34 (1984-86) EGR solenoid circuit shorted or open
    OR
    34 (1987-1991) speed control shorted or open
    35 Cooling fan relay circuit open or shorted
    OR
    35 idle switch motor fault - check connections
    36 (turbo only) Wastegate control circuit open or shorted
    37 Shift indicator light failure, 5-speed
    OR
    part throttle lock/unlock solenoid driver circuit (87-89)
    OR
    solenoid coil circuit (85-87 Turbo only)
    OR
    Trans temperature sensor voltage low (1995 and on)
    41 Alternator field control circuit open or shorted
    42 Automatic shutdown relay circuit open or shorted
    OR
    42 Fuel pump relay control circuit
    OR
    42 Fuel level unit - no change over miles
    OR
    42 Z1 voltage missing when autoshutdown circuit energized (The Z1 voltage is the voltage of the circuits fed by the autoshutdown relay. This typically includes fuel pump and switched-battery feed to the ignition coil)
    43 Peak primary coil current not achieved with max dwell time
    OR
    43 Cylinder misfire
    OR
    43 Problem in power module to logic module interface
    44 No FJ2 voltage present at logic board
    OR
    44 Logic module self-diagnostics indicate problem
    OR
    44 Battery temperature out of range
    45 Turbo boost limit exceeded (engine was shut down by logic module)
    46 Battery voltage too high during charging or charging system voltage too low
    47 Battery voltage too low and alternator output too low
    51 Oxygen sensor stuck at lean position (this may be tripped by a bad MAP sensor system causing a rich condition. If you get hot rough idle and stalling, especially on deceleration, accompanied by flooded engine and difficulty restarting, that can be a bad MAP sensor causing the O2 sensor to try to compensate. If you get poor cold driveability, stumbling and bucking, and acceptable warm driving with poor gas mileage (a drop of 10 mpg or more), that is usually the O2 sensor.
    OR
    51 Internal logic module fault ('84 turbo only).
    52 Oxygen sensor stuck at rich position
    OR
    52 Internal logic module fault ('84 turbo only)
    53 Logic module internal problem
    54 No sync pickup signal during engine rotation (turbo only)
    OR
    54 Internal logic module fault ('84 turbo only) - or camshaft sensor/distributor timing
    55 End of codes
    61 "Baro" sensor open or shorted
    62 EMR mileage cannot be stored in EEPROM
    62 PCM failure SRI mile not stored
    63 Controller cannot write to EEPROM
    64 Catalytic converter efficiency failure
    65 Power steering switch failure

    Member since 2000

    Jeeps Owned'79 CJ5:

    Specs-

    - 258 I6

    - '93 Cherokee fuel injection and HO head,

    - bored 30 over

    - with 4x4 cam

    T18 tranny with granny low / Dana 18 t-case

    Dana 44 front and back from late '70s Wagoneer, both locked and loaded with 4.88 gears

    SOA on modified YJ springs with shackle reversa

    Fiberglass tub with 6 point cage mounted to the frame


    2015 Grand Cherokee Limited
    Spec-

    Quadratec Floor mats

    Edited once, last by Slimer ().

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