'87 Cherokee Laredo, Renix, no fuel-pump ballistor in this model, 4wd and manual transmission.

Went for a drive in the rain, Jeep ran and started fine. Parked the jeep, and it wouldn't start.
No fuel pressure at the rail, so I replaced the fuel pump and filter. That didn't help. Long, strong crank, but no start.

You can hear the pump turn on when the key is first turned (6.8v at the harness), and then when you turn to crank the voltage drops to 3 something.
I've cleaned the C101, inspected the ECU, added a 4g ground from the block to the chasis, cleaned all connections in the engine bay, replaced the 02 sensor, replaced the CPS, and am still not getting any pressure or fuel to the rail.

Jeep will start with a bit of Starter Fluid. Pump will turn on from jumping 87 to 30 on the relay, but isn't moving fuel to the rail.
There is a spot where the pink wire for the fuel pump dips down next to the starter and there is a harness connection, on the other side of the harness is a small piece of wire that just connects the pink wire to the wire next to it. What is this?

What could be causing the pump to not receive power? Could it be something with the starter relay? or some other ground that I'm missing?

 

Welcome, Pokey. The Master Mechanic of all things Renix is the inimitable cruiser54. You will probably find your answer by following his Mostly Renix Tips. It's a good place to start.

 

Thanks BlueRidge! Long time reader first time poster. Most often I can read through the forums and find the solution, but this time no such luck.
I've been a huge fan of the Cruiser54 tips. Followed the maestro's tips: 1-6,8,9,11,19,20. I didn't do the fuel pump ground upgrade (which seems applicable) for two reasons. First, I couldn't find that ground, and second, the voltage problem is on the other side of the harness.

 

If it is an '87 without the ballast resistor TSB, then the fuel pump should not be connected to the starter relay. It eventually changes to an orange or orange/black if memory serves, and there are other relays powered from the switched side of the fuel pump relay. What is the voltage at diagnostic connector D1, pins 5 and 6 when you jump the fuel pump relay?

The C101 should not have anything to do with the fuel pump other than to remove the pump relay ground in order to change the state of the relay.

Silly question... is it possible your fuel rail pressure regulator has failed and most of your fuel is returning to the tank?

 

Well,

Looks like I've learned to check the pumps before you put them in your tanks...
First problem turned out to be that the replacement pump I'd gotten was non-operable out of the box.
Took the pump out of the tank, put it in a 5 gallon bucket of water plugged in, and it wouldn't do anything but hum. Plugged the Bosch pump I had removed from the tank originally, and it was spraying water.

Going to start a new thread for my new problems since they are not related to fuel voltage.

thanks for the replies and insight.