Fuel pump relay has power with key on. I am thinking it's a solid state ground from the ECU. I don't see a ground with ohm or diode function, but if I hook up the meter where the relay coil terminals go, I read voltage with key on. When I touch the relay to the terminals, the voltage reads zero, like the relay is shorting it out, but the coil measures 75ohms, just like the others. Any ideas?

Have you checked for fuel pressure at the fuel rail.

No pressure, no voltage at pump, so went to the relay. Whatever grounds the relay does it enough to read a voltage from, but not enough to trip the relay.

So you have 12V at the coil terminals until you plug in the relay, then it drops? Is that 12V measured to the ground / PCM terminal of the relay or another ground?

If so, then I agree you have a problem with the ground back to or inside the PCM.

Have you checked the voltage and what it measures to the battery ground? If it does the same thing, then maybe you have a bad connection or wire on the power side. A relay coil is not much of a load, but it sounds like you have something either shorting or loosing continuity under load.

I assume you've checked for power on the contacts / fuel pump side of the relay. Does a jumper on that side run the pump and provide fuel pressure?

have you swapped relay just to rule out the relay is bad ? just pick any relay from the master block that is the same to try this.

I had a no start issue on a 99 Dak once. It was the crank sensor in the bellhousing.

I believe it's like the old turbo dodge stuff...if no signal from the hall effect there will be no spark and fuel pump won't turn on (ASD relay) other than the initial ignition key on.

There's power to the relay measured to chassis ground. The voltage I measure at the relay contacts is probably just floating. If I touch the terminals, just the resistance of my body drops the voltage to 9v. What sends the ground to the fuel pump relay? Is there an impact sensor somewhere that turns everything off in a crash? What does the PCM look for before it turns on the fuel pump?

Below is from a 96 FSM, but I suspect your 98 is the same in this area. If you don't have one already I suggest Google to find a Factory Service Manual for your 98. Chances are you can find a pdf download. But in case you can't / don't find 98 see below. If this doesn't help I will lookup how to post pictures and grab the schematics. Just haven't tried to post any since the change. What I see in them though is power comes from the start / run side of the ignition to both the ASD and FP relays through fuse #9 (10A). The ground side comes from the PCM on both to control switching. Can't say I understand your statement about the voltage floating. But to answer your question, there are several inputs to the PCM that can kill the switching of the relays. If you have a fuel pressure test gauge, connect it and crank the engine to see if you are getting any pressure even momentary. If so, it could be your crankshaft position sensor.

FUEL PUMP RELAY-PCM OUTPUT
The PCM energizes the electric fuel pump and the
oxygen sensor (02S) heating element through the
fuel pump relay. Battery voltage is applied to the fuel
pump relay when the ignition key is ON. The relay is
energized when a ground signal is provided by the
PCM.
Refer to Automatic Shutdown Relay—PCM Output
for additional information.
The fuel pump will operate for approximately one
second unless the engine is operating or the starter
motor is engaged.
The fuel pump relay is located in the Power Distribution
Center (PDC) (Fig. 19).

AUTOMATIC SHUTDOWN (ASD) RELAY—PCM
INPUT
A 12 volt signal at this input indicates to the PCM
that the ASD has been activated. The ASD relay is
located in the Power Distribution Center (PDC) (Fig.
2). Refer to label on PDC cover for relay location. The
relay is used to connect the oxygen sensor heater element,
ignition coil, generator field winding and fuel
injectors to 12 volt + power supply.
This input is used only to sense that the ASD relay
is energized. I f the powertrain control module (PCM)
does not see 12 volts at this input when the ASD should be activated, it will set a diagnostic trouble
code (DTC).

Do you know if any codes are set? Key on/off sequence to get codes.

Also from the FSM:
GENERAL INFORMATION (Continued)
The PCM monitors the crankshaft position sensor.
If the PCM does not receive a crankshaft position
sensor signal within 8 seconds of cranking the
engine, It will shut down the fuel injection system.
The fuel pump is activated by the PCM through
the fuel pump relay.

So if your just turning the key on, or cranking for a few seconds and then checking for voltage, the PCM may have well already opened the ground circuit.

Testing the relays;
ASD AND FUEL PUiP RELAYS
The following operations/tests apply to these
relays only: Automatic Shutdown (ASD) and Fuel
Pump. These relays are located in the Power Distribution
Center (PDC) (Fig. 55). Refer to label on PDC cover
for relay location.
The relay terminal numbers from (Fig. 56) can be
found on the bottom of the relay.
Fig. 55 Power Distribution Center
• Terminal number 30 is connected to battery voltage
and can be switched or B+ (hot) at all times.
• The center terminal number 87A is connected (a
circuit is formed) to terminal 30 in the de-energized
(normally OFF) position.
• Terminal number 87 is connected (a circuit is
formed) to terminal 30 in the energized (ON) position.
Terminal number 87 then supplies battery voltage
to the component being operated.
• Terminal number 86 is connected to a switched
(+) power source.
• Terminal number 85 is grounded by the powertrain
control module (PCM).

TESTING
(1) Remove relay before testing.
(2) Using an ohmmeter, perform a resistance test
between terminals 85 and 86. Resistance value
(ohms) should be 75 ±5 ohms for resistor equipped
relays.
(3) Connect the ohmmeter between terminals number
87A and 30. Continuity should be present at this
time.
(4) Connect the ohmmeter between terminals number
87 and 30. Continuity should not be present at
this time.
(5) Use a set of jumper wires (16 gauge or smaller).
Connect one jumper wire between terminal number
85 (on the relay) to the ground side (-) of a 12
Volt power source.
(6) Attach the other jumper wire to the positive
side (+) of a 12V power source. Do not connect this
jumper wire to relay at this time.
CAUTION: Do not allow the ohmmeter to contact
terminals 85 or 86 during these tests. Damage to
ohmmeter may result.
(7) Attach the other jumper wire (12V +) to terminal
number 86. This will activate the relay. Continuity
should now be present between terminals number
87 and 30. Continuity should not be present between
terminals number 87A and 30.
(8) Disconnect jumper wires from relay and 12 Volt
power source.
(9) I f continuity or resistance tests did not pass,
replace relay. I f tests passed, refer to Group 8W, Wiring
Diagrams for (fuel system) relay wiring schematics
and for additional circuit information.

The PCM provides grounds. That includes the fuel pump relay. Find the wire (you really need the pinout diagram of the PCM) that provides that ground and check it. If the PCM is not providing ground then it is likely bad, but make sure it is grounded properly.

But, also bear in mind that when the key is turned on the fuel pump only runs for a few seconds to prime the rails. Then the pump will run when in start mode and run mode with the engine running.

By floating, I mean the meter has such a high input resistance, it can measure voltage without a ground, but there's no power or current behind it. The pump never turns on. There's never a spike of voltage to it when the key is turned on. There is no check engine light, but the bulb does work when first turned on. I can't read any CEL codes with the key on, key off dance, but I've tried that before when it did run and couldn't get it to display codes. The check gauges diagnostic has a 920 code: The cluster is not receiving a vehicle speed message from the PCM, and a 921 code: The cluster is not receiving a distance pulse message from the PCM, and 999 code: An error has been discovered. Next, when the gauges cycle through 1/3, 2/3, full deflection, the gas gauge stays at zero for 1/3 and 2/3 deflection, but goes to full with the other gauges. Does the PCM check the fuel pump module for something it isn't getting? I'm suspecting the PCM at this point since the gauges aren't receiving signals from it either.

Ya got me. Maybe someone that actually knows something will chime in. From what I see in the 96 FSM nothing on the fuel module connects to the PCM. The gauge side goes directly to the instrument cluster, the fuel pump only on the contacts side of the relay. Just the relay coil through the PCM.