Misfiring today....thinking it could be head gasket.

Discussion in 'KJ General Discussion' started by megatone, Nov 26, 2015.

  1. megatone

    megatone Full Access Member

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    2003 Jeep Liberty Sport 3.7L v6

    So today the Libby was driving fine.....it's my daughters Jeep. She'll occasionally take it up in the mountains and cross stream beds and rocky terrain (rocks the size of footballs). Nothing major. No hi rpm mud slingin' or anything like that.

    Anyhow, she picks me up and takes me out to lunch. The Jeep ran great. After eating, we got back in the Jeep and it would not start. When turning the key to engage the starter the only noise I could hear was that of the starter solenoid clicking very rapidly. Like when the battery is low.

    I have the Jeep towed home. I check the battery voltage. Battery volts held steady at 12.8 volts for 30 minutes (using a cheap volt meter). So I pull the battery out and take it down to a local Autozone so they can perform an actual load test on it. They inform me that the battery voltage is at 90% of what it should be, while sitting without a load on it, which it is fine. However, while under the load test, the battery amperage output drops down to 30% of what it should be. The battery was manufactured and purchased in April of 2013. The battery is a good Sears DieHard brand. I ended up going back to Sears and got a free replacement battery.

    Also, I had the starter tested during the same trip to Autozone. The starter passed all three of the electrical aspects of the test, Thier test machine said the starter was good. However, the solenoid was slow to kick out the starter gear when power was sent to it. And the gear was slow to retract back into its rested position, so I also bought a starter. I had the new starter tested before I left the store and it worked properly.

    So I get home, I install the battery and the starter (damn that stupid Chrysler V-band clamp on the catalytic converter). Anyhow, I tried to start the engine a few times with no success:

    First time trying to start the engine I insert the key, turn ignition and every light on the interior of the vehicle goes black (courtesey lights and dash bulbs). I again secured the battery post clamps and tightened the cable wires in the clamps (the battery clamps are the aftermarket type that you secure the strands of wire onto the clamps and then the clamps onto the posts. Second attempt at starting gave me one 'click' type of sound from the starter and then nothing. I again remove and replace the battery clamps, turn the key and the engine finally starts up with an instant misfire. OBD code was P0300 (random misfire). I go back to The Zone and get new plugs, I install them and now I am getting misfire codes for cylinders #1 and #2. I swap 1 and 2 coils with 3 and 4 coils......still getting misfire codes for 1 and 2. So I swap injectors, same results. I swap plugs, same results. I drive the Jeep for a 3 miles and the misfire goes away. My daughter takes the Jeep to her high school (uphill 15 miles away) to pick up her friends....she calls me up to inform me that the Jeep is running really bad. I have the Jeep towed once again to my house. I look under the hood to make sure no connections have came loose. I use my scanner and find cylinder 1 and 2 are misfiring again.

    I disconnect the a/c clutch and nothing changes (I have read that a bad a/c clutch can make the Chrysler-built engine misfire).

    I swap the ASD relay (under hood fuse panel)....nothing changed. Still misfiring.

    Checked ALL vacuum lines and everything appears to be intact.

    I did not check fuel pressure/regulator since the problem is now only associated with #1 and #2 cylinders.

    I applied dielectric grease to all plug and coil sockets.

    I checked all ground straps (well, as many as I could find) to be sure they are corrosion free.



    Electrical associated things that have recently been done to the Jeep include:
    Cooling system flushed with a chemical cleaning agent. Cleaning agent was in the system for 2 days (60 miles). Cooling system was then thoroughly flushed out and 50/50 HOAT coolant was added to the system. HOAT added today.

    Last week a professional stereo shop installed a 500 watt Alpine brand car stereo amplifier on the vehicle, to replace the same model that had water spilled on it.

    Replaced both head light bulbs with super bright units.

    And just today, my daughters boyfriend thought he'd do her a favor by detailing the engine compartment. He said he used Gunk brand engine degreaser and some type of spray soap and a garden hose.

    Gonna do a compression check tomorrow......because I love checking engine compression on Thanksgiving holidays......

    Just curious though, what is an unacceptable compression psi reading?
     
  2. LibertyTC

    LibertyTC Well-Known Member Staff Member Moderator

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    Is it turning over at all?
    Compression: between 170psi-225psi with no more then 25% difference.
    Link: http://www.jeepkj.com/forum/f196/compression-test-38727/
    Garden hose, water, engine clean. Coil packs got wet? Rubber seal on bottom of pack present?
    Use compressed air once coil pack removed, to get dirt / water out, then get plugs out...
     
  3. renegade 04

    renegade 04 Full Access Member

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    I think the real problem is when the engine compartment got detailed. I would start with disconnecting the battery to clear the codes and if the codes return then I would then go on to do a compression check. Also how many miles are on the jeep?
     
  4. HoosierJeeper

    HoosierJeeper Gold Supporter/Admin Staff Member Administrator

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    I had a misfire after using the same engine cleaner and going too heavy with the water. I took the coil packs out, let them dry overnight and cleaned them with Q tips. I also took the air compressor and blew the water out of the cylinder wells (where the coil and spark are those ares) and a shit ton of water blew out of there. Got it back together, ran a little rough but no misfire codes, drove it around for a half hour to evaporate what little water was left and all is good.
     
  5. megatone

    megatone Full Access Member

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    Yes, the engine turns over.
    The engine runs.
    Currently, there is no water/moisture in the engine compartment. Coils are completely dry.
    Spark plugs were replaced.
    Before removing plugs, I used compressed air to blow water out of the spark plug wells (so that when plugs were removed, the water would not drain down into the combustion chambers.
    Battery has been replaced. Removing the battery cleared the misfire codes.
    I used a code scan tool to clear the codes many times after each time I made changes to the coils/plugs/injectors etc...
    Engine has 138k miles on it.
     
  6. LibertyTC

    LibertyTC Well-Known Member Staff Member Moderator

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  7. belvedere

    belvedere Full Access Member

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    I wouldn't suspect a head gasket, as cyls 1 & 2 are on opposite banks.

    I think this is where I'd start. With the strands of cable exposed, corrosion can creep in and eat the cable from inside the insulation, where it won't be obvious. I would check the voltage drop across each cable while it's running.
     
  8. megatone

    megatone Full Access Member

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    DTC codes are P0301 and DTC P0302............which basically means cylinders 1 and 2 are b0th misfiring.......one cylinder misfire on each bank.

    I ended up reading Volts/ohms/mAmps/Amps/Continuity/etc....I ran all the tests and the coils are within specs. The engine continues to misfire.

    Tomorrow, I will drain all coolant from the system and start the engine, see how it runs....if it runs fine without coolant I will be suspecting the head gasket coolant passages.
     
  9. LibertyTC

    LibertyTC Well-Known Member Staff Member Moderator

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    Just because the coil packs test good, still don't mean it is any good. They tend to weaken over time.
    Did you try swapping coils by moving a bad one to another cylinder and see if the code moves with it?
     
  10. teeje

    teeje Full Access Member

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    This man not be your issue but there is always a possibility of having a bad crank/cam sensory. I've had tons of trouble with my Libby and put a new motor in. Make sure you figure out exactly what it is before you throw parts at it. A misfire could be caused by numerous things. Such as the cam/crank sensor, bad valve seat (the 3.7s are notorious for this, hell, might even be your issue. Try some marvel mystery oil if all else fails) I had a misfire issue before I bought a new reman motor and marvel mystery oil seemed to work.


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