Ok guys. This thing is getting on my nerves. 97XJ. Rebuilt the 300k motor. It was time. Did a few mods along the way (injectors, intake manifold, throttle body core etc) any it needs to be tuned up to get it running right. It’s running super lean and I have no power for a new engine. The only major mod was Chevy pistons milled to the top of the block face and the block was decked to within .10 of the head to increase compression.

Long story short. Took it to my mechanic to be tuned, He put it on a DYNO but his computer won’t interface with mine. He says it must have been flashed before and the last guy must have locked it so he can’t program it.
Has anyone run into anything like this before? He is using HP Tuners. Any help and advise would be appreciated.

 

I don't think hp tuners works with older Mopar computers like the XJ has, Flyin Ryan performance specializes in Mopar tuning, your best bet would be to contact them.

 

Hptuners newest interface does support Xjs but it’s only been that way for a short while. I would think the tuner would know that, though.

 

How lean is it running? Is it achieving closed loop and what are the fuel trims when it is lean? Does it ever run correctly when cold or hot?