This shows you do have a rich condition being compensated for by the PCM pulling fuel off.


New/rebuilt fuel injectors should fix this.


Try them before shot gunning sensors.

 

We need a photo shopped image of a shotgun with Jeep sensors flying out the end of the barrel at an XJ with the hood open!!!

 

That is good news then! I will report back after I get them swapped out. Thanks for all the helpful info!

 

LOL


That would be cool.

 

If you're going to do it, go for the upgrades !!!!!!!!!!!

 

I've got 8 703s soaking in seafoam right now, and my rebuild kit from Mr Injector should be here Saturday. I've trimmed up an o-ring to fit inside of a syringe, and a plug wired up with a momentary switch. Gotta find some heat wrap and I should have them in by Sunday.

 

Why the heat wrap?

 

I've read enough threads on heat soak being an issue. Figured while I have the injectors in my hands, I may as well go ahead and wrap them to prevent it later on. Bad idea?

 

Well, I just installed the 703s. Only tore 3 o-rings lol. The rebuild process went slow, but done well. Good thing I grabbed 8 from the jy, two of them leaked bad without any power going to them. Everything buttoned up nicely, no leaks. Touched the pos/neg together to discharge/reset the system. Fired up no issue, stumbled a bit at first, but hit the throttle a few times and she smoothed right out. We will see how it goes from here. I'll need to pick up some heat shield wrap soon and do that, but its still pretty cold here so I'm not worried about it yet.

 

4.0's prior to 2000 don't need that heat shield wrap. Save your time and money.


Edit: Hook up your scanner and see what the fuel trim is with the replacement injectors.

 

Good looking out, I won't bother with the heat shield.

I will pop the scanner on for the drive home today. Should the change in fuel trim be less drastic with the upgraded injectors? Or will it still go positives on accel?

 

Popped the scanner on for the drive home. I was seeing -15% to -1.6 slowly fluctuating at idle immediately after start up. I gave it a little blip and it went to 0 and then crept back down and sat at -8.2% for a minute. After I pulled out of the garage and really got moving, it went to +12.6 when taking off from a light under moderate acceleration, but fairly quickly settled down to 0 and then to -1.6 as I stopped accelerating.

By time I jumped on the express way, it was only fluctuating between 1.6 on acceleration and -1.6 during steady throttle.

I'm guessing that is just the ECU learning the injectors?

 

^ Could be.


When's the last time your Oxygen Sensors were changed?


If they've been in there for 190,000 miles they are due to be replaced.


If you are going to change your O2S's, change both. Use NTK sensors, not Bosch.

 

Finally replaced the upstream o2 with an NTK. I've had it sitting in the back for the last two weeks, but didn't have daylight hours to do it in the driveway until today. It idled much smoother and I had no more stumble or hesitation out on the road. The girlfriend might hate the Jeep a little less now. Thanks for all the help and knowledge!