SiDziner
Member
- Joined
- December 3, 2016
- Messages
- 16
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- Year, Model & Trim Level
- 2002 Explorer Eddie Bauer
2002 Eddie Bauer Explorer, 4.6L v8, 131k miles.
On the way home from work, my check engine light came on. I could feel the engine stumbling, so I figured I had a misfire. I got it home and pulled the codes : P0304 Cylinder 4 misfire.
I pulled cylinder 4 plug (last cylinder in the back on passenger side). The boot and plug were oily. The firing end of the plug was a little dark. I changed the plug and boot thinking that a little oil had gotten into the plug well and was causing the misfire. That did not fix the problem.
I then swapped the coil on cylinder 4 to a different cylinder. Still getting misfire code for cylinder 4.
I then checked the spark on cylinder 4 using a HEI ignition tester. the spark looked fine (blue) to me.
I checked the resistance of the #4 fuel injector. Honestly, i don't remember exactly what it was ... but i checked online and it was in the good range (11-18ohm). I compared it with the resistance of injectors on 2 other cylinders and it was basically the same (less than 1 ohm difference).
I didn't have the tools to do any more tests, so i took it to my local shop. He did a compression check on the right side and it passed (220). Fuel pressure was good, and the injector was firing. He pulled the coil and tested it and it passed. He even tried a new coil, but that didn't fix it.
He concluded that it was probably the PCM. He suggested taking it to the dealership and getting the PCM reprogrammed or getting a new one. I imagine either of those 2 options isn't cheap.
So, I have a few questions:
1) Is the problem likely the PCM at this point? Is there anything else that could/should be checked? I would guess PCM failure is rare (no basis for this, just guessing)
2) does reprogramming the PCM ever fix something like this? what would cause the programming in the PCM to get corrupted?
3) I *think* the PCM programming has some vehicle specific stuff in there. So I can't just swap in a new one. The new one has to be programmed, right? Any other options for getting a PCM than through the dealership?
thanks in advance,
George
On the way home from work, my check engine light came on. I could feel the engine stumbling, so I figured I had a misfire. I got it home and pulled the codes : P0304 Cylinder 4 misfire.
I pulled cylinder 4 plug (last cylinder in the back on passenger side). The boot and plug were oily. The firing end of the plug was a little dark. I changed the plug and boot thinking that a little oil had gotten into the plug well and was causing the misfire. That did not fix the problem.
I then swapped the coil on cylinder 4 to a different cylinder. Still getting misfire code for cylinder 4.
I then checked the spark on cylinder 4 using a HEI ignition tester. the spark looked fine (blue) to me.
I checked the resistance of the #4 fuel injector. Honestly, i don't remember exactly what it was ... but i checked online and it was in the good range (11-18ohm). I compared it with the resistance of injectors on 2 other cylinders and it was basically the same (less than 1 ohm difference).
I didn't have the tools to do any more tests, so i took it to my local shop. He did a compression check on the right side and it passed (220). Fuel pressure was good, and the injector was firing. He pulled the coil and tested it and it passed. He even tried a new coil, but that didn't fix it.
He concluded that it was probably the PCM. He suggested taking it to the dealership and getting the PCM reprogrammed or getting a new one. I imagine either of those 2 options isn't cheap.
So, I have a few questions:
1) Is the problem likely the PCM at this point? Is there anything else that could/should be checked? I would guess PCM failure is rare (no basis for this, just guessing)
2) does reprogramming the PCM ever fix something like this? what would cause the programming in the PCM to get corrupted?
3) I *think* the PCM programming has some vehicle specific stuff in there. So I can't just swap in a new one. The new one has to be programmed, right? Any other options for getting a PCM than through the dealership?
thanks in advance,
George