so today I installed the new fuel injectors in my 98 4.0 went to reset the ecu
and started up the jeep, idle is rough and has not smoothed out tried to drive it. and it backfired, need some help thanks

 

It may take several startup cycles for the computer to re-learn the new injector behaviors.

 

ok Thank you, i tried to restart it several times the jeep just kept having a rough idle and a lot of smoke from the tail pipe. It also backfired when i tried to drive it so i re installed the injectors.
that did not change anyting. so in the end i just placed the old ones back in i will try again another day
Thanks

 

One may have been bad out of the box (unless you mixed two connectors up)?

Unplug them one by one and see if you can detect a change in the engine while it is running. You should be able to hear a drop in RPM's if you unplug an injector that is working correctly. If you don't hear a change at all, that injector is probably not firing properly.

 

Swapped injectors many times on different Jeeps and had the same problem each time unless I reset the pcm.


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 jeep will now be in learning mode for the next 50 warm-up cycles where it will stop dumping fuel