Can't get rid of an engine light

Discussion in 'KJ General Discussion' started by DakMack, Dec 1, 2019.

  1. DakMack

    DakMack New Member

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    I'm new here and cannot figure out how to post a new discussion or tag but I'm trying to contact @WillBill and I'm having a similar issue as he mentioned above.. --Thanks all

    Hey Billwill, Dakmack here. I was reading a thread, looking for a solution to my 05 kj, pertaining to a misfire after a recent front end collision. New plugs(ngk copper/gapped. 40) started getting codes after them. New duralast coils as of yesterday and getting po300/po302. I wonder if you may have a picture of the wiring/harness/etc that was damaged and causing you issues after your front end collision. Thx for your time in advance
     
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  2. LibertyTC

    LibertyTC Well-Known Member Staff Member Moderator

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  3. Billwill

    Billwill Full Access Member

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    @DacMack where exactly was your front end collision?

    Was it front center, front left or front right? You sure Cyl #2 was not physically damaged?

    My Jeep is RHD Export 2002 2.5 CRD so I believe the wiring harness will be totally different. On my Jeep virtually all wires go around the complete engine bay like the Beltway Around Washington.
    A connection from say the front wiper to the BCM...a distance of about 18 inches...in my case goes all around the engine bay...through several connectors...through a metal pipe under the radiator and back again to the rear of the engine bay. This is a distance of about 6 feet!

    I have never seen a RHD 3.7 Gasser engine layout but from what I can see from the documentation, the wiring to the Plug Packs and the Injectors do not go too far up front but head backwards towards the Firewall and hence to the PCM.

    You will need to download the 2005 Jeep KJ Service Manuals here:

    www.colorado4wheel.com/manuals/Jeep/KJ/

    Go to Section 8W (Wiring) and print out page 8W-30-18 for the Injectors and page 8W-30-19 for the coil packs.

    We have to assume that a wire going to either coil pack #2 or going to Injector #2 has an intermittent break in it or an intermittent short to ground or some other random wire in the harness somewhere.

    You will need a cheap Digital Multi Meter.

    From the two diagrams you see that the top wires of the coil packs and the top wires of the injectors go to +12 volts in the wiring. It is unlikely that there is a fault in this section of wiring as your error code points only to Cyl #2 misfire...unlikely but not impossible! We will cover that later!

    So let us start with Page 8W-30-19 for the Coil On Plug #2.

    Disconnect the battery and the connectors on the PCM. and disconnect the plug on plug #2. Re-plug the connectors on the PCM several times in case of a bad connection, connect battery up again and test vehicle. If it still fails, disconnect battery and PCM again.

    So in theory the Dark Blue/Yellow (DB/YL) wire is hanging in mid air as it has been disconnected at both ends.

    With your meter set to Ohms measure this wire from end to end for perfect continuity...make sure you do not touch the meter ends with your bare hands or your body resistance will affect the reading! Best to tape small pins/needles to the meter leads so that you can piece the wire insulation if needed.

    While measuring this perfect continuity with the meter set to Ohms, shake the wire harnesses around to see if the meter reading suddenly drops!
    Now remove one of the meter leads and fix it firmly to ground somewhere.....should be no reading at all to ground. Shake the harness to see if you get a sudden reading to ground.

    Repeat this procedure using page 8W-30-18 for Injector #2 Brown/Dark Blue wire after pulling the connector from Injector #2.

    If neither of the above wires display a break/short intermittently...you have to physically cut off the leads at both ends and replace them with new wires.

    For example page 8W-30-19 the DB/YL wire for coil on plug wire has to be cut off near C2 pin 9 at the PCM and near the connector at Coil on Plug #2. Tape off the wire at both ends and replace with a new wire soldered onto the cut-off ends and insulated at both end.

    If that does not fix the problem repeat the above for the Injector #2.

    Lay the new wires over the existing harnesses and tape them down neatly.

    Drastic measures but what has to be done if all else fails!:eek:

    If that does not work...you have to repeat the above procedures for the +12 volt wires Red/Orange or Pink/Grey going to the Coil #2 and Injector #2..unlikely here that there is short to ground as it would affect all cylinders but there may be a break in the wires!
     
    Last edited: Dec 2, 2019
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  4. DakMack

    DakMack New Member

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    Firstly, thank you @LibertyTC for your insight on posting! Replying here on a smartphone as my laptop is down. Bare with me @Billwill
     
  5. DakMack

    DakMack New Member

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    @Billwill an extensive thanks first off! From what I have read the main wiring is different for the CRD than gassers.

    My collision was on the right side of the vehicle(passenger). The worst of it was radiator/condenser/trans cooler/header panel/cosmetic etc including front bumper shell(garbage plastic anyhow). There was not any body damage as in metal body/paint and related.

    I tore everything that was damaged, bent and broken out and replaced it all. While doing this though, I encountered a main wiring pigtail that plugs in behind the driver side headlight. It travels across the header panel(that was damaged) to the passenger side headlight. I do not think it's a continued circuit, meaning it stopping at passenger headlight. Other wiring behind lighting, drops down to running and blinker in the front bump.

    I bought new plugs today(NGK copper v-power) and plan to disconnect battery and install them, examine coil connectors and wiring close by. I will grab the continuity tester and start the process of elimination as you described after downloading the charts you mentioned.

    Also to add, I had no issues before changing my spark plugs(before collision). After changing the plugs, I was immediately hit with po113 code - IAT sensor (in intake tube, outside throttle body), and the po300 code - multiple cylinder misfire. I replaced the IAT sensor and cleared the codes.

    Both codes continued to flash periodically but I had no loss in power etc till after my collision.

    My main concern is that if I may had pulled a wire loose when originally changing my plugs bc I couldn't get the coil connectors unclipped. They were pulled taunt(misfire?) And I also removed the intake air tube(po113 intake air temp sensor?) all when throwing the plugs in.

    Oddly enough that I had the codes before the collision, I had no loss of power, rough idle, bucking etc that I do now after this mishap of n accident happened.

    I trimmed my airbox down as it was cracked in the accident(more open/flow now) and threw a k&n drop-in in there. Just put on a cat back exhaust also for a state inspection. Other than what I've mentioned I'm stumped.

    I appreciate your time and please let me know if anything I've mentioned has caught your attention as I'm aware of your fondness to libbys.

    Thanks- Dakmack
     
  6. LibertyTC

    LibertyTC Well-Known Member Staff Member Moderator

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    The Jeep Wants these ! Make sure gap is correct.
    [​IMG]
    Are these the plugs you have ready?
    Only use MOPAR Sensors.
    You do need to remove the coil pack connectors to change the plugs, does this help?
    [​IMG]
     
  7. Billwill

    Billwill Full Access Member

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    Worth trying new plugs, swapping injectors over and checking the Fuel Pressure Regulator as mentioned here before climbing into the wiring in a major way.!

    On my 2002 Export CRD I had about 11 errors coming up one at a time since the collision end December 2007.

    There was major damage to the harness up front which was impossible to get to due to the harness running inside a thick square metal pipe under the radiator. So I had no choice but to go through the long process of tracking down bad wires and replacing them.

    I had weird problems....for example if I turned ON the front wipers the DC voltage would steadily run up to 17 volts at which time the engine would cut out. I was monitoring the voltage while driving with a meter plugged into the front Power Outlet point.
    I was at the time doing a long trip during a major storm...had to turn the wipers ON/OFF in short bursts. By the time I got home the battery had boiled itself to destruction.

    About a three months ago I got my latest error...this I traced to a bad wire intermittently shorting to chassis/another wire somewhere right back against the Firewall...causing a MAP Sensor error.
    This area was way out of the way from the front collision but after 17 years this wire slowly wore its insulation down somewhere within the harness causing the problem.:(

    If I had sold this Jeep years ago I would pity the poor new owner..fortunately I know my Electronics and retired early so had the time to fix these wiring issues myself!;)
     
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