P0303….At the end of my patience and wallet
- Thread starter bubbad323
- Start date
OverlanderJK
Resident Smartass
Yeah stick with the plug connector before anything else. This happened when you broke that connector. Logic says start there.
Clip isn’t in stock anywhere. Going to throw a new spark plug in today and see if that helps. If so great. If not then I’ll change the clip and also flip coil packs to rule out a faulty one. After that I’m waiting the white flag and moving on.
OverlanderJK
Resident Smartass
Can you fit a zip tie over it? That would keep it tight and let you know if that’s the issue.
Just put a new spark plug in and still getting a misfire at idle. The clip actually seats well without the locking piece. I put some electrical tape on it for now and it’s on there good. Going to swap coil
Packs in a little and see if that has any change. If not then I’ll actually change the clip to rule out the connection. After that I’m at a loss. Have a real love/hate relationship with these jeeps.
SpikesHD
Member
I'm betting this can be solved much cheaper than buying a new vehicle, no matter the cause.
Damn. Many more carefree miles to you. Swapped the #3 and #1 coils. Same result do those are ruled out. Whats left. Fuel injector? Doubt it since no sluggishness and engine runs fine. No hint of hesitation or power loss. Electrical? Maybe. More serious issues that would come up with a compression test etc? She has 130 on her so maybe it’s time. Sigh
OverlanderJK
Resident Smartass
When I had low compression my light would come in and off. Can’t remember the code though. Think it was $2400 at the dealer for new head and labor.
bobfriesenhahn
Hooked
Leak down test (usually best) and compression test are different things. By buying a compression tester, you can do your own compression tests. To do the compression test, you remove all the plugs, and attach the compression tester to each spark plug location, cranking the engine for each one location. Look for variations, and abnormally low pressure in a cylinder. If low pressure is discovered, add a squirt of oil to the cylinder (enough to get on the rings) to see if this creates a much better pressure after a few cranks. If this substantially boosts the pressure then the cylinder/rings have a problem, otherwise there is likely a head/valve issue.
If the cam shaft lobes are worn so the valves do not fully open, this is likely not detectable by a leak down or compression test.
GP NOIR
Hooked
Is this the clip you’re looking for? I used this kit to replace broken coil connectors on my 2012
Thanks. I can’t swing that repair cost. I already threw a lot of money into this thing. Just hasn’t felt like there is ending to it. Also have a rear main seal leak and that’s also costly.
Looks doffermt than the OEM ones but I’ll have to take a closer look. I don’t think the clip is the issue but gonna change to rule out regardless. Of course it’s on cylinder 3 which is the hardest to work on due to the metal plate and no room. SMH.
GP NOIR
Hooked
Although it looks different, it worked. They have a different lock mechanism than OEM. It’s also possible I misunderstood which connector you need.
Latest…
Ordered a compression test kit and tested the suspect cylinder 3 and adjacent cylinder 1. Both coming up with 170 psi. Not sure what the specs should be but they were identical. I’m assuming these readings are good and rules out any compression issue with cylinder 3?
Since I have done this test, installed a new spark plug, swapped #3 and #1 coils….next is to replace the ignition coil clip that has the broken lock. As my luck would have it, there’s little to no room to work on taking this clip off due to a plate and heater tubes. PITA.
The dealer, when testing some wires on one of the harnesses, didn’t tape up the wires they accessed. Idiots. I’ll be putting electrical tape on to cover.
If my compression test truly means there’s no issue there (hoping someone more knowledgeable than me on here can chime in) then I’m not going to be so quick to get rid of her. Fingers crossed. Hopefully this saga being documented here helps someone else in the future.
Ordered a compression test kit and tested the suspect cylinder 3 and adjacent cylinder 1. Both coming up with 170 psi. Not sure what the specs should be but they were identical. I’m assuming these readings are good and rules out any compression issue with cylinder 3?
Since I have done this test, installed a new spark plug, swapped #3 and #1 coils….next is to replace the ignition coil clip that has the broken lock. As my luck would have it, there’s little to no room to work on taking this clip off due to a plate and heater tubes. PITA.
The dealer, when testing some wires on one of the harnesses, didn’t tape up the wires they accessed. Idiots. I’ll be putting electrical tape on to cover.
If my compression test truly means there’s no issue there (hoping someone more knowledgeable than me on here can chime in) then I’m not going to be so quick to get rid of her. Fingers crossed. Hopefully this saga being documented here helps someone else in the future.
bobfriesenhahn
Hooked
I am not sure what the reading should be, but it sounds very strong to me. And you had said the engine runs well under load.
If not electrical, maybe it could be an issue with a fuel injector?
Thank. Yes the engine runs great. If I did the compression test right and there’s nothing wrong there then I’m going to continue trying to figure this out.
bobfriesenhahn
Hooked
Compression, fuel, spark, timing, ... and some sort of sensor to decide if it is working as expected.
semicolon
Active Member
This may not be possible for you but... There's an exceptional diagnostic technician about 300 mi from you in Avoca. His YT channel is South Main Auto. He does some impressive troubleshooting on difficult issues, very technically competent. If I were in your shoes I would consider making the trek. I've burned many hours watching him solve oddball problems that other shops are unable to. In one of his videos he troubleshoots a P0303 on a 2017 Wrangler.
Last edited: