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Ticking / misfire /check engine light.

SavioAZ

NAXJA Forum User
Location
AZ
hey everyone. New to the forum and pretty new to XJ's. hoping to learn some new things.

ok here is what happened:
Changed my oil last month and went 10w-40. motor didnt like that and gave me some lifter tick. it's not the regular "lifter tick"we get, its the loud "tap tap tap tap" with rpm's. tapping is right on the top of the valve cover-drivers side.

so i changed to 5w-40 T6 the next day which i read a lot of 4.0's love. its been 2 weeks and the ticking is still there. and on top of that. i got a check engine light... the car drives normal and idles normal even when cold. however only if i floor it i can feel it misfiring.. very low power. i checked the code for the check engine light. it says cylinder 2 lifter.

now, i talked with a couple local jeep guys that i see occasionally about this.. one said rip the head off and get the lifters done. the other guy says even tho it says its the lifter, he thinks it could be carbon build up on the intake valves and to seafoam the system through the brake booster line. if that doesnt work, flush the oil with some atf and go lighter in oil cause maybe the lifter is stuck. if those fail, then get the lifters replaced...

My question to ya'll is should i listen to either of them? do you have other suggestions? this is my daily driver, should i just take it into a shop and get the lifters replaced? i live in an apartment complex and don't really have much room to do engine work. and im kinda nervous about doing it myself honestly. :dunno:

thanks!
 
It could be lots of things, or it could be nothing. What you need is a diagnostic from one, or better yet two, trusted mechanics with knowledge of the Jeep 4.0L.

What trouble code numbers are you getting from the Check Engine Light, I have never seen any lifter trouble codes ?
 
well it's definitely something because of the power loss when the check engine light came on when i floor it.. also it has new spark plugs and wires. and i forgot to say but the motor has 147k miles.

one of the guys is a mechanic at a local shop. he also drives an xj (the guy suggesting the seafoam etc)..
i dont remember the code that popped up. i was at autozone where the other jeep guy works, and when he put the module in the computer the screen popped up and said cylinder 2 - lifter...
 
There is no specific code for lifters, perhaps you meant misfire? I too would recommend ignoring your armchair mechanic friends who want you to start with pulling the head before doing some more basic diagnostics such as a compression test. Get the code and we can advise from there.
 
oh yes, misfire. sorry. yeah let me get the code later tonight. and its just odd its misfiring only when i want to drive fast? driving to and from work, as long as im taking it easy and drive like a normal human being everything is fine (other than the loud annoying tapping) just nervous about the tapping. im a worry wart.
 
Here are the codes PO302 - misfire cyl 2 , and PO202 injector circuit / open cylinder 2 (this one is new, code showed up today)

Here is an update. On my way home the ticking went away... but I had bad misfiring. I pulled over and unplugged the injectors one by one while idle. Cylinder two when disconnected there is no change in the rough idle. So I got a new injector on my way home. Will install tomorrow.and replace them all down the road.
My guess is the ticking cylinder is now not even moving? Because the injector clogged? Could the ticking have been from a failing injector? Or am I just unlucky and have two things at once , a lifter issue and a clogged injector.
 
No guessing allowed.

Solve the known issues, using the trouble codes to guide and focus your diagnostics and testing, and see if the observed symptoms go away. If not, continue with a logical testing and diagnostic plan for the more common and more logical causes of the observed symptoms.



P0202 JEEP - Fuel Injector 2 Circuit Open


P0202 JEEP Possible Causes
•Faulty fuel injector 2
•Fuel Injector 2 wire harness is open or shorted
•Fuel injector 2 circuit poor electrical connection



P0302 JEEP - Cylinder Misfire Fault Detected


P0302 JEEP Possible Causes
•Faulty spark plug 2
•Clogged or faulty fuel injector 2
•Fuel injector 2 wire harness is open or shorted
•Fuel injector 2 circuit poor electrical connection
•Ignition coil 2 harness is open or shorted
•Ignition coil 2 circuit poor electrical connection
•Insufficient cylinder 2 compression
 
Last edited:
SparkPlugs and wires are 2 weeks old. I’m replacing the injector today and will test the injector harness as well. Will update you once that’s done.
 
Update: changed out the injector. Fired her up, and still misfiring. When I unplug the wire from the injector no change in idle. So I’m starting to believe it’s the wire to the injector. Any way to test this? Or any other thoughts on the matter?
 
Another update: took the jeep down the street to the mechanic. He did an entire inspection, compression test etc. he told me that a sensor wigged out my ECU causing nothing to happen with my #2 fuel injector. Which soaked my cylinder walls. Spark plug was soaked. And the compression was shot in that cylinder. Codes went away when he unplugged and replugged that sensor for the speedometer under the tranny. He told me that I will need a rebuild or a new motor... and I’m freaking out now cause this is my daily driver and I’m don’t have 4K to fix it.
 
Another update: took the jeep down the street to the mechanic. He did an entire inspection, compression test etc. he told me that a sensor wigged out my ECU causing nothing to happen with my #2 fuel injector. Which soaked my cylinder walls. Spark plug was soaked. And the compression was shot in that cylinder. Codes went away when he unplugged and replugged that sensor for the speedometer under the tranny. He told me that I will need a rebuild or a new motor... and I’m freaking out now cause this is my daily driver and I’m don’t have 4K to fix it.


Maybe try to find a Junkyard donor motor?
 
The yards around me don’t have any. I called them. I did find some on Craigslist etc. but I’m nervous about them being garbage and them me ending up in the same boat I am now. I did however find a site to buy reman motors. There pricier for sure (1600) but they allow monthly payments. So that would save me financially. And they warranty them for 100,000 7years. I’m exploring that option. The company is called sandjengines ? I found them through another forum member.
 
Are you in Az?
 
yeah im Gilbert AZ. the motors here shouldnt be all rusty and sticky. but some of these motors ive seen online have no oil cap or the intake is off and i can see all kinds of dust in there.
 
ill check it out. and on tuesday im taking it in to my usual mechanic to get a second opinion. he usually has some good options/connections with people.
 
Update: Going to need a new motor. no compression in cylinder 2 and some lower end knock.
would it be safe to drive at least 30 minutes at 45mph to a shop i know of that could install the new motor for me?
also any recommendations for companies to go with for reman motors?
 
Why exactly would a fuel injector that "isn't doing anything" 'soak' the cylinder and wash away your compression?
 
Idk. Both mechanics say I have no compression in cyl 2. (Motor only has 140k on it) First mechanic originally said oh it’s just the ECU. But then upon further inspection he noticed the compression being gone also.. and then spark plug soaked, and scorched cyl walls. So he said the ecu most likely told the injector to spray constantly? I’m not entirely sure of anything anymore, Except that I have no compression.
 
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