no haven't checked voltage for switch yet, I cannot figure out which type I have.
took under dash off no box with a slider bar in it like book says. I think it is the one that is in the column, which I don't have a puller for. or maybe not looking in right place?

Thats the thing I am getting voltage for the CPS with switch in RUN position but is it the right voltage is my question? .20 on one .18 on two 0 on three round plug: slot on bottom: left, right, bottom

no pinched wire at CPS or loose connector

 

Do the cherokee's have a Fuel Cut Off Switch? It sounds like that could be it if your rig turns over, but no fuel pump prime or fuel. IF they do this is most likely it. Worth a shot since it would be an easy fix.

 

ok found switch checked all voltages they are good through all switch positions and there is switched voltage to ECM but I still have no CEL for bulb check at key. Checked bulb it is good and is being supplied voltage as well.

 

Here is my vote

http://www.naxja.org/forum/showpost....91&postcount=1

 

The MAP Sensor? plz explain reasoning

 

i think he's saying balist resistor, would that cause no pulse? i'm not really sure.

i can't remember, did you find and check ignition relay, and fuse?

 

Ahh... Well the ballast resistor is fine. checked with ohm meter (says on it what ohm it should be)
just no power is running through those wires, can hook direct voltage to them and pump will run, traced wires I think no voltage is being sent from ECM to resistor relay which runs to pump relay to pump motor. too many relays if you ask me....
I checked voltage from the grn/blk wire that runs from ECM to resistor relay and there is no voltage at all with key in RUN
I got in touch with our local Jeep Guru from R&R Custom Jeeps and he is looking for a ECM that I can test with. So I am going to see how that pans out

 

that sounds like the next step, computers don't fail much, but it sounds like yours could be.

 

not sure if the 91's use the same sequences as the renix setup or not....but if you're checking the ballast it may NOT have constant 12 v. Aside from the bypass when starting, mine seems to have a timer function: turn key to run, and it runs the pump through a primer sequence, then cuts of after 12-15 seconds. probably to protect the pump, would be my guess. ( lots of the Bosch based euro systems work this way, BTW.) make sure you're quick, or get someone else to turn the key to run while you check for power at the ballast...

Found this out the hard way myself when trying to diagnose a ballast/fuel pump issue.

sounds like a jumper wire might also be a handy diagnostic tool for you - try jumpering the wire at the ballast from the battery 12v+, and see if you can hear the fuel pump run. if it does, and the Jeep will start while the jumper is in place, at least you'll only have to work back up the fuel pump wiring.

 

Hey all

Here is a little update...

Finally found a ECM on ebay that matched my numbers got it today and slapped it in. Turned the key and fuel pump primed and CEL came on and she fired right up. let her run for about twenty minute with no problems at all.
Found out the ECM's were only supposed to last 8-10 years in the cherokees, somehow mine made it 18 years. So everything is good now.

Thank you for all your help

 

thats great you found the problem. i've never heard of xj computers having a shelf life. it isn't a real comon occurance. thanks for posting the fix.

 

Great thing to hear!!! no more of this hahaha

 

Well everyone here knows about jeeps (Just Empty Every Pocket)

Pulled into the driveway today and the brakes on the front were smoking, got under to look and saw nice, pretty, orange flames. The brakes were dragging all day, luckily I only drove to town and back(about 7 miles round). Rotors and pads are now crispy, and calipers are hopefully ok. Think it might be a bad master or booster from that '86 I got. Booster was pretty rusted and full of water when I cleaned it.

Oh well such is my life.... At least it runs now!!!

 

You don't happen to be "lovesappy2" do you? If so, I recently sold an ECU on ebay for $20. If it was for you...glad it helped!

 

not sure what cps sensor stands for, but when mine didnt start i replaced the crank censor.. not sure if thats what you listed, but i thought id throw it out there