I sold my daily driver on Friday last week, and started driving the Jeep, on Saturday the CEL came on, the code was P0201, Cyl 1 Injector circuit. The Jeep seemed to be running fine so I cleared the code. All was fine then on Monday on my way home, the whole jeep started shaking violently, and the CEL came on again. This time there were two codes, P0201 and P0301 (Cyl 1 Misfire). I replaced #1 injector and it was fine until the next afternoon when it got hot and I had the A/C on. Again, the CEL was on and the code was P0201. So, I replaced the Coil Rail thinking maybe it's failing, also swapped #1 plug with #3 plug to eliminate a plug failure. All was well today until I pulled into the driveway this afternoon. Again engine at operating temp, A/C on and the whole Jeep started shaking again. This time, no CEL, just an extremely rough idle. Removing the connector on Injector #! had no affect, removing the connector on any of the others resulted in an even rougher idle, so it still seems to be something with the #1 cylinder. Let it cool down a couple hours, just went out and fired it up, and it's purring like a kitten! Any ideas what I should look at next? I feel I'm just throwing expensive parts at it and they aren't fixing it! Thanks...
Intermittent problem with my TJ, need help!
- Thread starter Gotta-P
- Start date
SteelHeadz
Super Moderator
Check the wiring on that injector all the way to the PCM. I'm thinking there might be a break in the wire that has continuity on light loads and looses contact inside the wire when it gets hot. The best tool to use on this is a multimeter by testing the wire resistance between the injector connector to the PCM connector pin. A spread pin will also cause this issue.
What is a spread pin? I have a multimeter, but not sure how to know which wire at the PCM to check. I did put a test light on the wires that connect to #1 fuel injector and I'm getting a good steady pulse. Fuel Injector #1 was just replaced and is brand new, but when I pull the wire connector from that injector while the engine is running there is no noticeable difference in how the engine runs... Maybe I got a bad injector? Although yesterday when it was really rough, it never threw a code...
SteelHeadz
Super Moderator
Spread pin connector means the female side of the pin connector is partially spread and will intermittently loose connection. Each electrical connector althrough out the vehicle consist of a male and female connectors. You will need a wiring diagram to trace out the wiring in question between the injector to the PCM. Color coding of the wires also helps finding the wire between each component.
