Hi and thank you all in advance for any help you will provide.
Symptoms:

• Car starts/runs well under all conditions except during/after rains.
• After a rain, key is turned to position II & fuel pump does not fire as normal (2-3 seconds).
• I have learned that if you leave the key in position II and wait b/t 10 and 40 seconds, the fuel pump will fire some point as normal & then it starts fine if you finish turning the key.
• If you don't finish turning the key after waiting for the fuel pump to fire, and you pull key out and try again, you still need to wait at least 10 seconds for the fuel pump to fire. However, once you actually start the car... if you turn it off and re-try, there is no delay in the firing of the fuel pump.

Actions:

• Replaced MFR per some recommendations/threads just in case.
• Pulled ECU from passenger foot well & it's PERFECTLY dry in that entire area after days of hard rain. The unit looks CLEAN & impeccable inside & out. Board looks great, no bad spots. Did not test all capacitors and such b/c ultimately I don't see how moisture would be affecting its function directly at the unit.
• I've loosened/tightened all the grounds i can locate on the car (though could've missed a critical spot i suppose)
• I checked the distributor area and appears very dry and well sealed. I see no intrusion of water in the engine compartment during/after a rain.

Somehow, moisture is affecting an electrical connection that eventually 'works' if key remains in position II. Please help.


I am able to use a multi-meter.



Thank you again for reading and providing advice!

 

1. Raise the front section of the Spare Tire lid.
2. Disconnect the 3 P Connector.

CAUTION: Be sure to turn the ignition switch "OFF" before disconnecting the wires.

3. Connect the RED/WHT (5) wire and BLK/YEL (4) wire with a Jumper Wire at the
PGM-FI Main Relay Connector.

1. Check that Battery voltage is available at the Fuel Pump Connector when the ignition switch is turned "ON" (positive Probe to the BLK/YEL wire, negative Probe to the Body Ground).

•  
  • If Battery voltage is available, replace the Fuel Pump.
  • If there is no voltage, check the Fuel Pump ground and Wire Harness.

 

Thank you. The car is currently starting. However, I did a dry-run to ensure that I got the anticipated result. Indeed I have 12v as soon as i turn ignition to position II. I will have to wait until the next rain and corresponding no-start. At least the practice helped me to make a good jumper wire and be ready for a quick check next time.

Thank you and stay tuned for a report.

 

I completed the recommended test. I DO get voltage even when the pump is not firing. However, it seems these wires that i've been told to test go to the sending unit and not the pump? Also, the pump is in the gas tank, so how could rain/moisture adversely affect its performance. I'm still thinking it's got to be in the wiring under the car leading up to the fuel pump.

Ideas? Further tests?

 

the testing i gave you is from the manufacturer...based on that, it's time to change the pump.