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86 Daytona running issue

Discussion in 'Daytona and Laser' started by Jason89, Dec 20, 2016.

  1. Jason89

    Jason89 Member

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    My 86 Daytona's RPMs all of a sudden dives at 3000 RPMs. So anytime I put the pedal to the floor the engine dives down then recovers when I pick up my foot. I checked the TPS voltage and it is OK.
    Thanks!
     
  2. Jason89

    Jason89 Member

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    UPDATE:
    My 86 Daytona's RPMs all of a sudden dives at 3000 RPMs. So anytime I put the pedal to the floor the engine dives down then recovers when I pick up my foot. I checked the TPS voltage and it is OK. Some other weird things:
    Code was 56.
    Battery symbol lights up when cranking engine
    Charging almost 16 volts

    Maybe limp mode without Power Limited light..
    Thanks!
     
  3. Doug D

    Doug D Virginia Gentleman

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    There's no ODBI code of 56. 55 is end of codes.
    The ODBI Code listing (from Allpar) is as follows:

    Code 11The engine has not cranked since the battery was disconnected.
    Code 12 The battery has been disconnected and the computer (ECU) has been reset.
    Code 13 MAP sensor signal to the computer (ECU) not changing
    Code 14 MAP sensor signal out of range
    Code 15 No signal received by the computer (ECU) from the speed sensor
    Code 16 Battery voltage drop below ‘normal’ when engine running
    Code 17 Coolant sensor not reporting more than 160° after 8 minutes of engine running
    Code 21 Oxygen sensor reporting too lean or too rich after 2 – 12 minutes with temp over 170° and RPM above 1500
    Code 22 Coolant temperature sensor out of range
    Code 23 Air charge temperature sensor out of range
    Code 24 Throttle Position Sensor (TPS) signal out of range
    Code 25 Air Idle Speed motor shorted or voltage out of range
    Code 26 1985 + Turbo models: engine injector driver circuit one shorted or open
    TBI models: injector peak current not achieved
    Code 27 Turbo engine injector driver circuit two shorted or open
    Code 31 Purge Solenoid open or shorted
    Code 32 Power Limited light lamp failure
    Code 33 A/C relay open or shorted
    Code 34 84 – 87 models with EGR, EGR solenoid open or shorted
    1987 and later models: cruise control servo failure
    Code 35 Radiator fan relay open or shorted
    Code 36 Wastegate or other solenoid open or shorted
    Code 37 Baro-read solenoid open or shorted
    Code 41 Alternator field control circuit open or shorted
    Code 42 1984 model injector circuit 1 open or shorted
    1986+ models: ASD relay open or shorted
    Code 43 Ignition coil driver circuit open or shorted
    Code 44 1984 logic module diagnostic failure
    1985-86 battery temp out of range
    1987+ Signal to J2 not present at SEMC
    Code 45 Turbo engines boost above predefined range
    Code 46 Battery charging voltage out of range
    Code 47 Battery charging voltage out of range
    Code 51
    Code 52
    1984 engine running too rich or lean
    1985+: code 51=running too lean, code 52=running too rich
    Code 53 Logic module fault
    Code 54 Signal loss from the fuel injector sync pickup during engine rotation. (HEP)
    Code 55 End of fault code list

    Your probably getting a code 46 - Battery charging voltage out of range - which would confirms the 16 voltage (overcharging). Battery voltage with the engine running should be 14.3-14.4 volts and 12.6 volts with the engine not running.

    From Allpar (Chrysler Fault Code 46: Battery charging voltage out of range):

    Code 46 is triggered when the voltage sense input is more than one volt above the target voltage for 20 seconds, as sensed by the computer. When code 46 is triggered the power limited light will be lit and the system will not enter limp mode. When the charging voltage falls below one volt of the target voltage the power limited light will go out but the code will still be stored.

    Possible reasons include poor wiring or connections (see ‘How to troubleshoot drivability issues’, check the wiring and connections from the logic module to the power module, and clean and re-grease the connectors with dielectric grease); or a defective voltage regulator circuit (see Diagnosing Your Charging System).
     
  4. Bob Lincoln

    Bob Lincoln "CHECK FAULT CODES"
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    Yep. 16 volts is going to fry light bulbs and a lot of the electronics.
    Look for a bad ground everywhere that you can find one - all of the wires off the negative post of the battery at both ends, look at the alternator harness closely. There may be a field problem with the alternator. High voltage will throw off the MAP, TPS and CTS sensor readings, which will change the air/fuel mixture and the effective dwell angle/ignition timing.
     
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  5. Jason89

    Jason89 Member

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    Correction on the code. it was a code 54. Thanks.
     
  6. GLHS60

    GLHS60 Well-Known Member

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    That's normally the HEP, the electrical pickup under the distributor cap.

    Wiggling the wires with the Engine running often replicates the issue.

    The tach droping a split second before stalling is a good clue.

    Replacements are often poor quality so used is a possibility.

    They interchange from 1986 up 2.2/2.5, Turbo is different than TBI

    Overcharging is another issue.

    Thanks
    Randy
     
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  7. Bob Lincoln

    Bob Lincoln "CHECK FAULT CODES"
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    Before replacing, check the HEP harness, especially where it goes under the dist cap; and check the connector where it plug in. Those are often the true failure points.
    Could also be a slightly wobbly distributor, or could be accumulation of metallic particles from wear, which ground the spark from rotor to dist shaft or the metal pickup vanes.
     
    Doug D likes this.
  8. Laser86

    Laser86 Member

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    a friend of mine has a home made trailer that was welded together to carry motorcycles .... and whenever he pressed the brake pedal of the towing vehicle the lights on the back of the trailer would come on but very dimly ......... I traced this to a bad ground, but the bad ground to the brake lights was being caused by the " welded joints " not making a good connection from the front of the trailer to the rear of the trailer, they did NOT have a ground wire from the front to the rear, they used the trailer itself ....... I am thinking it may not be a bad idea to run a ground wire ( 12 or 14 gauge, or whatever is required ) in combination with a body ground to anything critical that uses the body only as a ground due to the body " spot welded " joints possibly becoming less conductive through the years ...... just my thoughts ......

    does anyone know how is the fuel pump grounded on an 86 Laser ? is it a body ground or a wire from the battery ?
     
    #8 Laser86, May 14, 2017
    Last edited: May 14, 2017

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