00 XJ running terribly with lots of codes.

[123Grains]

I believe I found my answer but I'm concerned about resetting the PCM because it's been programmed with a Superchip tuner. Am I being paranoid about it?

The Electronic Control Module, or ECU as its commonly called, stores the information for your vehicle and your driving habits in its memory. The memory is maintaned by a series of capacitors that hold a charge and maintain power for the ECU when the vehicle is turned off. The following procedure will allow you to reset the memory and allow the computer to 're-learn' how to drive by adjusting to the drivers habits and the vehicles modifications.

1. Disconnect the battery by removing the positive battery cable. Remember, the positive battery cable.

2. Ground the positive cable to the negative cable for 30 seconds to erase the electric charge in the capacitors.

3. Reconnect the positive cable to the battery.

4. Turn the key to on but do not start.

5. Turn the headlights on.

6. Turn the headlights off.

7. Turn the key off.

The ECU has now been reset to its FACTORY SETTINGS. For the next 50 warm-up periods the ECU will re-learn the engine and driving habits for your driving conditions and the newly installed parts.

 

[Tim_MN]

Resetting the PCM does not alter the programing, it simply clears the memory.

 

[Talyn]

Correct. Resetting is fine.Why has it been reprogrammed?

 

[123Grains]

It was reprogrammed with the Superchip tuner for claims of increased HP and MPG. I tuned it about two years ago.

 

[123Grains]

I stand corrected, she is still backfiring under load. Joy.

 

[Digger87xj]

#1 priority is to figure out why 3 and 6 are misfiring.

I would not be concered about fuel pressure until you verify the gauge accuracy.


I can't recall for sure but 3 and 6 might be companion cylinders on the coil pack. meaning that 3 and 6 share the same coil.

 

[123Grains]

Okay, I'll have to remove the coil and check resistance for each section. It's always possible that my new coil is DOA.

 

[randomguy310]

I still say its the cps..

 

[sidewaysstarion]

I believe I found my answer but I'm concerned about resetting the PCM because it's been programmed with a Superchip tuner. Am I being paranoid about it?

The Electronic Control Module, or ECU as its commonly called, stores the information for your vehicle and your driving habits in its memory. The memory is maintaned by a series of capacitors that hold a charge and maintain power for the ECU when the vehicle is turned off. The following procedure will allow you to reset the memory and allow the computer to 're-learn' how to drive by adjusting to the drivers habits and the vehicles modifications.

1. Disconnect the battery by removing the positive battery cable. Remember, the positive battery cable.

2. Ground the positive cable to the negative cable for 30 seconds to erase the electric charge in the capacitors.

3. Reconnect the positive cable to the battery.

4. Turn the key to on but do not start.

5. Turn the headlights on.

6. Turn the headlights off.

7. Turn the key off.

The ECU has now been reset to its FACTORY SETTINGS. For the next 50 warm-up periods the ECU will re-learn the engine and driving habits for your driving conditions and the newly installed parts.

can you show me in the wiring diagram where the ecu interfaces with the headlight circuit? :huh:

 

[123Grains]

No, unfortunately. I found this posted in another forum, I'm not sure what significance the headlights have to resetting the ECU. I was just trying to be proactive by answering my own question. Here's the link to the post I located. http://www.xjtalk.com/showthread.php?t=9402

 

[Tim_MN]

..... where the ecu interfaces with the headlight circuit? :huh:

The PCM reset process really does work. One might suppose that the PCM senses activation of the headlights. When combined with the all the necessary steps, adaptive memory is erased.

 

[123Grains]

I think need to do a compression test and also visually inspect the valve springs. I'm getting a spooky feeling about this.

 

[Talyn]

One might suppose that the PCM senses activation of the headlights.

If it was on a WJ or ZJ I might believe that, not on an XJ.

 

[shelbyluvv]

I've done the PCM reset and it works. It will barely run when you fire it up the first time.

Is the Superchip a piggy back plug in pill? If so remove it and plug the harness directly into the ECU. I had a similar issue and it was the TPS. Have you gotten the Jeep wet lately? Do you have hood vents installed? The TPS on my 00 did not like water at all.

 

[123Grains]

I haven't gotten it wet lately and I do not have hood vents. The superchip programmer plugs into your OBDII port and acts like a scan tool with the option to flash your ECU with a performance program. It advances the timing and optimizes shift points. Once it is done you simply turn the key off and remove the superchip programmer. You never need it again unless you want to return your ECU to the original program or scan your CEL.

 

[winterbeater]

I think need to do a compression test and also visually inspect the valve springs. I'm getting a spooky feeling about this.

Yes. Compression test. Never can understand why everyone wants to ignore the simple cheap diagnostic and just start changing parts.

 

[123Grains]

Anyone could forget the basics, myself included, when they are rushed with a daily driver that they desperately need. I've been working on mine during lunch breaks and after work. It's quite easy to forget the simple stuff and overanalyze a diagnostic session.

 

[randomguy310]

any luck yet?

 

[123Grains]

Unfortunately, I haven't been able to put her in the garage in weeks and it will be a while before I can. Thank you all for the help and I'll revive this thread when I can start working on the poor old girl again.

 

[gradon]

I'd uninstall the Superchips tune just to take it out of the equation.