paying 300 for some one to fix this xj

Ok narrows down to bad ecu... Has anyone seen injector circuit in an ecu go bad? Number 1 injector not firing.. Hooked up light to it and every one lights up except number 1
 
using a dvom check for 12v to that injector with the switch on. if not open the harness to see why?
if you do have 12v then unplug the ecu and find the ground from ecu to that injector and check for continuity in that wire. if you dont have continuity open the harness to see why?
if the wiring checks out ok then yea you may need an ecu.
 
Hmm.. if one injector has power then they should all have power correct?.. checked with meter and wasnt getting ground signal from ecu.. Didn't find any shorts where it's grounded out or anything ( which would cause out it stay open anyway right?) Swapped ecu.. Same problem... .. Ok here is something wierd I noticed.. #1 injector is the one that won't light up with the noid light ok will just fiddling around I unplugged the number 2 injector while I had it running.. And there was no change in idle at all
 
untchabl said:
If you can keep it running with the throttle, try driving it around for 15-20 mins. My 99 didn't want to idle after the battery died, was told the computer had to relearn idle, etc. drove it around for awhile and it was good to go.
Click to expand...

My 99 acted the exact same way when the battery completely drained. What I did to get it to idle was keep the rpm up for 10 min then I put it in reverse and reved it with my foot on the brakes and then when I shifted back into park it idled fine.
 
Do you make sure that your throttle body and manifold are clean when you swapped them. My Cherokee did the same thing, and had to flush the system and then it ran fine, except I had to replace one of my O2 sensors afterwards. I don't remember the product name, but it was around $90-100 for it.
 
Also flash the ECU by grounding both cables together. Put em back on the battery. Turn ign switch to ON, turn on headlights, turn off headlights, turn key off. Done. Computer will relearn any changes for the next 50 starts.

Also, test or replace the TPS, and clean the IAC in the TB. TPS is often the culprit...it also affects trans shifting.
 
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