1. Welcome to Jeeps.net!

    You are currently viewing as a guest! To get full-access, you need to register for a FREE account.

    As a registered member, you’ll be able to:
    • Participate in all Jeep discussion topics
    • Transfer over your build thread from a different forum to this one
    • Communicate privately with other Jeep owners from around the world
    • Post your own photos in our Members Gallery
    • Access all special features of the site

Sluggish acceleration, misfiring and more

Discussion in 'Cherokee' started by Willibrooks, Mar 12, 2017.

  1. Mar 12, 2017 at 9:45 AM
    #1
    Willibrooks

    Willibrooks [OP] Member

    Joined:
    Mar 12, 2017
    Member:
    #1137
    Messages:
    10
    Gender:
    Male
    First Name:
    William
    Vehicle:
    1994 jeep cherokee
    I have a 1994 Jeep cherokee, the day I bought it the transmission line busted everywhere under the hood the guy I bought it from failed to clean it correctly. Now I have issues. The jeep will crank and run good but when the motor gets warmed up and the engine gets shut off it fails to recrank and you can smell gas. Check engine light will come on with code 14 and did 51 which 15 means map sensor has not enough/to much voltage and 51 is saying bad map sensor or o2 sensor. I replaced both and the map connector as well. Jeep has amazing power now but all of a sudden the symptoms came back were sluggish to accelerate and miss firing in the motor. I noticed the o2 sensor connectors was lose a little and had some trans oil in it. Cleaned it up and ran perfect yet again. After jeep sits the idle is ruff but only about 20 to 30 secs and idles perfect. Could the left over trans fluid be my problem and could it ruin anything else?
     
  2. Mar 12, 2017 at 12:18 PM
    #2
    chris4x4

    chris4x4 With sufficient thrust, pigs fly just fine Moderator

    Joined:
    Jul 19, 2016
    Member:
    #2
    Messages:
    4,042
    Gender:
    Male
    Welcome! I'm not sure what this would be caused by, but hopefully someone will be able to give some input
     
  3. Mar 14, 2017 at 6:50 PM
    #3
    OFFGRID

    OFFGRID Well-Known Member

    Joined:
    Oct 3, 2016
    Member:
    #317
    Messages:
    2,018
    Gender:
    Male
    First Name:
    Peter
    Houston
    Vehicle:
    1979 Jeep CJ7, 258, TH350, NP208
    Howell fuel injection, header, HEI distributor, TH350, NP208, SOA lift with YJ springs in the front & GW springs in the Rear. AMC20 with G2 1 piece chromos trussed, Dana 30 with G2 chromos and 760x ujoints and MM Stainless Hubs, Geared 4.56. Tom Woods shafts, Metal cloaks, Caged, 37" Toyo MTs.
    I read in the dealer service manual that the Jeep will run in closed loop mode bypassing all sensors until it reaches operating temperature then it switches to open loop and the computer takes over reading all sensors. It could be any one of them causing this. The IAC, TPS, Temp, map, O2 (you've already replaced) etc. Make sure your throttle body is clean as well.
     
  4. Mar 15, 2017 at 6:15 PM
    #4
    Willibrooks

    Willibrooks [OP] Member

    Joined:
    Mar 12, 2017
    Member:
    #1137
    Messages:
    10
    Gender:
    Male
    First Name:
    William
    Vehicle:
    1994 jeep cherokee
    Well now I have another proublem... the o2 sensor fixed some of the issues. But now the alternator went out. I fixed that and now it's still saying it's not chargeing? And it back fires in the motor so hard it almost knocked off the air intake and throttle body
     
  5. Mar 15, 2017 at 10:17 PM
    #5
    OFFGRID

    OFFGRID Well-Known Member

    Joined:
    Oct 3, 2016
    Member:
    #317
    Messages:
    2,018
    Gender:
    Male
    First Name:
    Peter
    Houston
    Vehicle:
    1979 Jeep CJ7, 258, TH350, NP208
    Howell fuel injection, header, HEI distributor, TH350, NP208, SOA lift with YJ springs in the front & GW springs in the Rear. AMC20 with G2 1 piece chromos trussed, Dana 30 with G2 chromos and 760x ujoints and MM Stainless Hubs, Geared 4.56. Tom Woods shafts, Metal cloaks, Caged, 37" Toyo MTs.
    Cam and or crank sensor maybe.
     
  6. Mar 16, 2017 at 3:01 PM
    #6
    Willibrooks

    Willibrooks [OP] Member

    Joined:
    Mar 12, 2017
    Member:
    #1137
    Messages:
    10
    Gender:
    Male
    First Name:
    William
    Vehicle:
    1994 jeep cherokee
    Thank you. I got a mechanic coming Saturday morning with a tester.
     
  7. Mar 18, 2017 at 11:51 AM
    #7
    Willibrooks

    Willibrooks [OP] Member

    Joined:
    Mar 12, 2017
    Member:
    #1137
    Messages:
    10
    Gender:
    Male
    First Name:
    William
    Vehicle:
    1994 jeep cherokee
    Now I have a new issues the guy who came out and checked my alternator says it's works just fine problem is there is no power going to it so the battery won't charge. He took off the positive and negative to the alt to check if power is going and to make sure it wasn't wired wrong. Get it all back going and power to the alt. Turned car off cleaned up some then took it for a drive. The car ran good then all of a sudden no power again. And the battery is not getting no charge. Any help would be awsome.
     
  8. Mar 18, 2017 at 10:28 PM
    #8
    OFFGRID

    OFFGRID Well-Known Member

    Joined:
    Oct 3, 2016
    Member:
    #317
    Messages:
    2,018
    Gender:
    Male
    First Name:
    Peter
    Houston
    Vehicle:
    1979 Jeep CJ7, 258, TH350, NP208
    Howell fuel injection, header, HEI distributor, TH350, NP208, SOA lift with YJ springs in the front & GW springs in the Rear. AMC20 with G2 1 piece chromos trussed, Dana 30 with G2 chromos and 760x ujoints and MM Stainless Hubs, Geared 4.56. Tom Woods shafts, Metal cloaks, Caged, 37" Toyo MTs.
    Did you figure out what was causing the power disconnect the first time? What do your battery cable and connects look like? Are you getting the chalky build up on the terminals that many seem to get?
     
  9. Mar 19, 2017 at 8:01 AM
    #9
    Willibrooks

    Willibrooks [OP] Member

    Joined:
    Mar 12, 2017
    Member:
    #1137
    Messages:
    10
    Gender:
    Male
    First Name:
    William
    Vehicle:
    1994 jeep cherokee
    After the first set of issues the 02 sensor fixed most of the problems. Now the alternator went out in it completely dead had it tested and all so I replaced it. After watch the mutimeter for about 30 mins last night just trying to get a better understanding the alternator starts charging and stops. When it charges no back fire and has so much power, when it's stops charging backs fires and loses power. Weird thing is the battery dose not go below 12.2 voltage when its not charging but when it does it reaches 14.3. I know the voltage regulator is built in to the ecu it's self and rarely fails. Is there a fuse for a 1994 Cherokee se 2.5 motor? Or could I have a lose wire going to the ecu?
     
  10. Mar 19, 2017 at 8:23 AM
    #10
    Willibrooks

    Willibrooks [OP] Member

    Joined:
    Mar 12, 2017
    Member:
    #1137
    Messages:
    10
    Gender:
    Male
    First Name:
    William
    Vehicle:
    1994 jeep cherokee
    A guy told me also that the voltage regulator that connects to the bottom of the alternator that the pig tails could be lose or bad to check them. Any more helpful hits would be awsome
     
  11. Mar 19, 2017 at 2:24 PM
    #11
    Willibrooks

    Willibrooks [OP] Member

    Joined:
    Mar 12, 2017
    Member:
    #1137
    Messages:
    10
    Gender:
    Male
    First Name:
    William
    Vehicle:
    1994 jeep cherokee
    Update

    As of now my Jeep is running great. The issue was lose bolts going to the alternator at the km bottom. Thanks everyone for the help.
     
    chris4x4 likes this.
  12. Mar 19, 2017 at 5:39 PM
    #12
    chris4x4

    chris4x4 With sufficient thrust, pigs fly just fine Moderator

    Joined:
    Jul 19, 2016
    Member:
    #2
    Messages:
    4,042
    Gender:
    Male
    Glad you found the issue!! That's a strange one to have!
     
  13. Mar 20, 2017 at 4:58 AM
    #13
    Willibrooks

    Willibrooks [OP] Member

    Joined:
    Mar 12, 2017
    Member:
    #1137
    Messages:
    10
    Gender:
    Male
    First Name:
    William
    Vehicle:
    1994 jeep cherokee
    Yeah it was.
     
  14. Mar 20, 2017 at 10:43 AM
    #14
    Willibrooks

    Willibrooks [OP] Member

    Joined:
    Mar 12, 2017
    Member:
    #1137
    Messages:
    10
    Gender:
    Male
    First Name:
    William
    Vehicle:
    1994 jeep cherokee
    Never mind it didn't fix it... anyone wanna buy a jeep lol
     
  15. Mar 20, 2017 at 12:30 PM
    #15
    OFFGRID

    OFFGRID Well-Known Member

    Joined:
    Oct 3, 2016
    Member:
    #317
    Messages:
    2,018
    Gender:
    Male
    First Name:
    Peter
    Houston
    Vehicle:
    1979 Jeep CJ7, 258, TH350, NP208
    Howell fuel injection, header, HEI distributor, TH350, NP208, SOA lift with YJ springs in the front & GW springs in the Rear. AMC20 with G2 1 piece chromos trussed, Dana 30 with G2 chromos and 760x ujoints and MM Stainless Hubs, Geared 4.56. Tom Woods shafts, Metal cloaks, Caged, 37" Toyo MTs.
    It sounds like you have 1. loose positive or ground wires to and from the battery, possible between the alternator and battery, or 2. corroded positive and negative cables to and from the battery, and again possibly between the battery and alternator. Jeeps get outfitted with lots of electronic accessories and with such a draw on the battery the result is over time corrosion of the wires. (see picture A below). To fix this you need a stronger aftermarket alternator that consistently gives more positive power going to the battery than is being taken from it. A severe case of corrosion shows up on both the battery terminals and the cables (see picture B below). If your battery cables are corroded like these then you will have symptoms similar to what your are describing.

    A

    corrosion2_940ef1885374f21830228c9988c82a9e1fbf5cd9.jpg

    B

    [​IMG]
     
  16. Mar 20, 2017 at 2:47 PM
    #16
    Willibrooks

    Willibrooks [OP] Member

    Joined:
    Mar 12, 2017
    Member:
    #1137
    Messages:
    10
    Gender:
    Male
    First Name:
    William
    Vehicle:
    1994 jeep cherokee
    No corossion on terminals. Terminals are new. I might have a striped nut or bolt that alternator I'll have to check.. this jeep has been giving me issues I think I might sell it and try over. The guy who sold it to me knew the proublems I belive cause it's just one thing after another.
     
To Top