06 Jeep Wrangler X Bad Miss fire

David Overbay

TJ Enthusiast
Joined
Jan 21, 2016
Messages
125
Location
Clarksburg , WV
So I got my new computer in today and it was supposed to be pre flashed. I installed it and the jeep wouldent turn over so luckily i have a guy local that said he wouled re flash. So i threw the old computer in and limped it about a mile to the shop changed out the computer and they tried to reflash and still nothing. Besides that the mechanic said he thinks its something different. It has a bad miss and am not getting anything from injectors 3 and 4. When full is poured in it runs like a champ. What i have done so far to fix the problem i have put in new plugs, fuel rail, cam positioning sensor, replaced all o2 sensors, and knocked the cats out. Cant get nothing on a scanner. Also we have checked wiring and nothing seems to be wrong with it were getting power just no fuel. BTW im no mechanic so if this makes no since thats why.
 
My guess is that it's related to the new ECU, not something else. I personally would bring it back to that mechanic and have them check it out.
 
The new ECU wont do anything the mechanic pulled it apart and there is a missing component in it. Besides that we put the old ECU in it and he thinks that theres a different problem but don't know where to start looking because if the old ECU is bad he said that it shouldn't even start and if it does then it shouldn't stay running.
 
It might be worth buying a used ECU for the right setup (manual or auto tyranny) and correct year. Plug that in and see if it works. That would be a good way to isolate whether it's the ECU or not.
 
It might be worth buying a used ECU for the right setup (manual or auto tyranny) and correct year. Plug that in and see if it works. That would be a good way to isolate whether it's the ECU or not.
I have tried to find one but cant since the 06 was the only year to have that exact ECU its pretty hard.
 
I have tried to find one but cant since the 06 was the only year to have that exact ECU its pretty hard.

That means you could use an 05-06 ECU since they were the same. You'd just have to make sure (I think) that it came from a vehicle with the same transmission as yours (i.e. auto or manual).

If this were my rig I would look at it this way:

Has it ever run fine (without any issues) since you bought it?

If the answer is NO, then how did you (or your mechanic) determine the ECU was the culprit as oppose to something else?
 
Since i bought it no but i bought it from a friend and it ran good. The second one
What i have done so far to fix the problem i have put in new plugs, fuel rail, cam positioning sensor, replaced all o2 sensors, and knocked the cats out.
Also run tests on injectors to know 3 and 4 is not getting power but the wiring is in good condition and has power all the way up to the injectors they aren't firing we have switched the injectors and it remains 3 and 4
 
If you disconnect the connector plug at injector 3 and 4 and run a 12v test lamp between the two pins on each connector, you can see the ECM switching the individual injectors as you turn the engine over. If you don't see the test lamp, your ECM is not switching that injector.
 
If you disconnect the connector plug at injector 3 and 4 and run a 12v test lamp between the two pins on each connector, you can see the ECM switching the individual injectors as you turn the engine over. If you don't see the test lamp, your ECM is not switching that injector.

Good call! Didn't even think about that. Stellar advice.
 
Day in and day out, troubleshooting electrical components is what I do for a living.
Usually not on vehicles though. I dabble in 480-2400 volts most of the time, up to 69,000 on a bad day.
 
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Reactions: Chris
I should have thought of that since I'm always using my test light. Good call though, I obviously missed that one.