fuel pump not clicking on

alright ive been reading and searching through threads for a couple hours now trying to not have to start a new thread that might have already been talked about.

when i turn my key to the on position i can hear a couple clicks but not the normal buzzing from the fuel pump. which is why i believe my jeep wont start. i took my multimeter and tried checking the voltage at the fuel pump where the electrical plug is and since im new at using a multimeter im not sure what it was telling me. the best reading i got was 6 volts. every thread i have read says that if the pump isnt "buzzing" when i turn the key then its probably the CPS. i tried changing one of the relays and switching them around and such but still no luck. im at college and have a limited amount of tools (or auto-mechanically inclined friends) but any suggestions would be nice.

btw, its an 87' 2.5litre manual.

when you turn the key to the "on" position it should buzz for about 2 seconds to prime the system. I'm not quite sure about yours but my '91 does this and every other jeep I've seen. I'm not sure if the CPS controls the power to the pump, as I'm pretty sure it controls the injectors. However, there is a ballast resistor somewhere in the circuit (everyone I've seen is on the drivers side fender). It looks like a little white plastic box with two wires clipped onto it. You can try jumping that with whatever you've got. Someone please correct me if I'm wrong here, but I had to deal with a couple bad fuel pumps that just turned out to be a bad ground in the tank.

Could be a bad ground but... either way you have to drop the tank so might as well replace the pump.

Two common failure points, other than the fuel pump itself, are the Fuel Pump Relay and the "Ballast" resistor, as already mentioned. The ballast resistor is there to reduce pump voltage to reduce pump NOISE, by slowing it down. You can jumper the two connections without harming the fuel pump.
You can check fuel pump voltage under the hood by using the Diagnostic Connectors located on the passenger side fender well, near the relays. Pin 6 of the small connector (it only has 6 pins) should give you the voltage going to the pump. Put your meter's positive lead in pin 6 and connect the meter's negative lead to ground. I've not done this with the ballast resister in place, but I'd expect to see 12v or more with the fuel pump plug at the tank disconnected. With the plug connected, and the pump running, I'd expect less than 12v, but I don't know how much less. I'd check the voltage at pin 6 with the plug connected, then with it disconnected and record the values. The difference in values will be due to the pump drawing current, which should result in less voltage when connected. Voltage on pin 6 indicates the Fuel pump relay is working. Insufficient voltage on pin 6 implies the ballast resistor is faulty. Put a jumper wire accross the ballast resistor and check the voltages again; however, if the ballast resistor is the culprit, the pump should run correctly as soon as you bypass the ballast resistor. If you have voltage at pin 6, and you have bypassed the ballast resistor, and the pump still does not run, it indicates a bad connector at the tank, or a bad pump.

thank you all for those tips. as soon as i get done with classes today im going to try those and ill let ya know what happened

alright. i checked the voltage at the number 6 pin and it reads around 12 volts. then i checked it at the fuel pump and it reads around 6 volts. i cant find the ballast resistor. my radiator overflow tank is where the resistor is on pics that i have seen. i took that off just to see if it was maybe underneath it and of course it wasnt. whats next?

found the problem. i ended up taking the pump out of the tank and plugging it back into the wiring harness. it worked fine so i started looking at it and where the ground connects to a metal pipe inside was broken which caused the pump to come ungrounded. so basically a little soldering job and it will be fixed. thanks for your guys help