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No start- fuel pump not coming on, gauge not working

Lightfoot

NAXJA Forum User
Location
fort collins co
so today I was messing around under the hood, installing an adjustable map sensor on my 99, got everything hooked up and ready to go, and went to start it and got nothing. I started the engine just before the install, and it worked great, ive never had fuel problems before. So i uninstalled the sensor, re hooked up the wires, and still nothing. There is no fuel getting to the rail. I tested the pump with a direct connection, and it works fine, Though it does not cycle when you turn the key. I tried swapping relays around, disconnected the battery, and checked all connections, and fuses under the hood. nothing. I noticed that the gauge is also reading completely empty, and I know for a fact I have a half tank.
Any ideas would be great. Thanks
John
 
no check engine light. Ive pulled and inspected every fuse under the hood, and most of them inside the jeep. I also put 5 gallons in it to make sure i didnt get siphoned or something. I cant find a wiring diagram anywhere, but clearly the problem is something related to both the gauge and the pump. Any help is appreciated, i really need this thing running by the end of the weekend.
 
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sometimes a sensor will short out on the 5 volt circuit and the pcm will lose communication. it usually is the crank sensor. try to unplug each sensor one at a time to see if the check engine light will come back on. you may have to cycle the key after each one. you might want to start with the map, since you were working with that one. maybe an o2, cam sensor, etc.
 
Alright so ive gone through every sensor under the hood and underneith, unplugged and inspected each, and re connected. I also rechecked all fuses. Ive tried cycling the key, and still have nothing new. It wont throw a code, and i also determined it will not spark. This is leading me to think its cps like you said, but i do not ave an extra to swap in. Ill do an ohm test and see what it says. Is it possible to kill your cps shorting out the system?
 
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