I have a 96 Honda Accord that has trouble starting after a rain or any real moisture in the air. When the ignition is switched on the fuel pump will not come on/prime. I know this because I can hear the pump come on also there is a green square light that surrounds the D4 area only when the pump energizes. Once this happens the car will start fine with no problems. I may have to turn the switch on several times, some as many as 10 times until the pump comes on, once this happens as I have said above the car will start. Once it starts I can turn it off and do it again and sometimes it doesn't take it long for it (the pump/light) to come on. If I was to drive it for a couple of miles and it warms up it will run great. I don't know if there is something that gets wet and just needs to dry out or what.
I have changed the main fuel pump relay under the dash and done a fuel pump test. Like I said it works fine except for when it rains or there is heavy moisture in the air. This is my daughters car, I am about to pull my hair out any help or advise would be great! Thanks in advance!

1. Does the Check Engine Light consistently come on for 2 seconds and then go out, when the ignition switch is turned to ON (Position II)? If not, clean the main ECM ground, located on the thermostat housing. If the CEL sometimes stays on, the ECM may be intermittently failing, which is not uncommon on Hondas of this generation. Perform the K-Test on the ECM, when the CEL stays on. If the voltage is a fraction of a volt, buy and install a remanufactured ECM--shop for price and warranty.

2. During this two second interval, do you consistently hear the fuel pump run and then stop?

To eliminate hard starting, during humid and wet weather:

. Remove the O-ring from the distributor housing, coat with silicone grease, and reinstall. If it's missing, mashed, or deteriorated, install a new O-ring. Moisture may be getting past the O-ring and shorting out the ignition inside the distributor cap.

. Install a new distributor cap, rotor, and spark plug wires, if they have not been replaced in 60,000 miles. Moisture may be penetrating breaks and pores in the spark plug wires and shorting out the ignition system.

. Weatherproof the electrical system by carefully removing each under hood and under dash fuse, cleaning the contacts with abrasive cloth, coating the contacts with dielectric grease, and reinstalling each fuse. Disconnect the negative battery cable first. Ensure each fuse fits snugly--slightly twist each tang, if needed.

. Ensure the ECM is high and dry and not getting wet.

. Check the ignition switch for wear, pitting, or melting, if the problem persists.

1. Does the Check Engine Light consistently come on for 2 seconds and then go out, when the ignition switch is turned to ON (Position II)? If not, clean the main ECM ground, located on the thermostat housing. If the CEL sometimes stays on, the ECM may be intermittently failing, which is not uncommon on Hondas of this generation. Perform the K-Test on the ECM, when the CEL stays on. If the voltage is a fraction of a volt, buy and install a remanufactured ECM--shop for price and warranty.

2. During this two second interval, do you consistently hear the fuel pump run and then stop?

To eliminate hard starting, during humid and wet weather:

. Remove the O-ring from the distributor housing, coat with silicone grease, and reinstall. If it's missing, mashed, or deteriorated, install a new O-ring. Moisture may be getting past the O-ring and shorting out the ignition inside the distributor cap.

. Install a new distributor cap, rotor, and spark plug wires, if they have not been replaced in 60,000 miles. Moisture may be penetrating breaks and pores in the spark plug wires and shorting out the ignition system.

. Weatherproof the electrical system by carefully removing each under hood and under dash fuse, cleaning the contacts with abrasive cloth, coating the contacts with dielectric grease, and reinstalling each fuse. Disconnect the negative battery cable first. Ensure each fuse fits snugly--slightly twist each tang, if needed.

. Ensure the ECM is high and dry and not getting wet.

. Check the ignition switch for wear, pitting, or melting, if the problem persists.




The CEL comes on and goes off after appox. 2 sec. and the fuel pump will come on during and then go off, guess it is a cycle it goes through something like a prime. Once that happens then the car will start as advertised.The problem I am having is after a rain the pump will not come on after the CEL comes on and goes out. I have to wait either to hear the pump come on or see the light surround the D4 on the instrument panal. (The light will come on during the prime and then go out) once that happens the car starts fine until the next rain then I start all over again.

The CEL comes on and goes off after appox. 2 sec. and the fuel pump will come on during and then go off, guess it is a cycle it goes through something like a prime. Once that happens then the car will start as advertised.The problem I am having is after a rain the pump will not come on after the CEL comes on and goes out. I have to wait either to hear the pump come on or see the light surround the D4 on the instrument panal. (The light will come on during the prime and then go out) once that happens the car starts fine until the next rain then I start all over again

The problem I am having is after a rain the pump will not come on after the CEL comes on and goes out.

The fuel pump is not supposed to come on after the CEL comes on and goes out. You should only hear the fuel pump run during the two second interval that the CEL is on. Here's how to check the fuel system.

Fuel System Troubleshooting

This is a two-part problem: 1) Determine if the fuel pump works, and 2) Determine why the PGM-FI Main Relay doesn't work properly.

If you don't hear the fuel pump run, when the ignition switch is turned to ON (Position II):

Problem 1: Determine if the fuel pump works.

1. Disconnect the main relay from the main relay connector. Jump main relay connector Terminals 5 and 7, turn the ignition switch to ON, and listen for the fuel pump in the gas tank. If you can hear the fuel pump run, which is usually the case, it is likely good and you should proceed to Problem 2. If it doesn't run, go to Step 2.

2. Turn the ignition switch ON. Measure voltage between main relay connector Terminal 5 and ground. If there's not battery voltage, test/replace the ACG (ALT) (S) (15 A) fuse in the under dash fuse/relay box. If necessary, repair an open in the wiring between the main relay and the ACG (ALT) (S) fuse. Verify that you now have battery voltage to Terminal 5. If the fuel pump still doesn't run, however, go to Step 3.

3. Check for continuity between main relay connector Terminal 7 and the fuel pump. If necessary, repair an open in the wiring. If the fuel pump still doesn't run, go to Step 4.

4. Check fuel pump. Even though it's certainly possible, I have never seen a Honda fuel pump fail. They are very reliable. Clean connections and thoroughly test pump motor, prior to replacement. Before going any further, all efforts must be focused on getting the fuel pump to run (i.e. solve Problem 1 first), when main relay connector Terminals 5 and 7 are jumped and the ignition switch is turned to ON. If the main relay and fuel pump still don't work properly together, however, go to Problem 2.

Problem 2: Determine why the PGM-FI Main Relay doesn't work properly.

5. Check for continuity between main relay connector Terminal 2 and body ground, with the ignition switch OFF. If there's no continuity, clean the main ECM ground, which is usually located on the thermostat housing. Look for 3 wires going to a brass connector. Remove the 10mm bolt, clean with No. 240 abrasive cloth, and apply dielectric grease. If necessary, repair an open in the wiring between the main relay and the main ECM ground. If there's continuity, go to Step 6.

6. Measure voltage between main relay connector Terminal 1 and ground. If there is not battery voltage, test/replace the ECM fuse (15 A) in the under hood fuse/relay box. If necessary, repair an open in the wiring between the main relay and the ECM fuse. If there is battery voltage, go to Step 7.

7. Turn the ignition switch to START. With manual transmissions, depress the clutch pedal. With automatic transmissions, the gear selector must be in Neutral or Park. Measure voltage between main relay connector Terminal 6 and ground. If there's not battery voltage, test/replace the STARTER SIGNAL (7.5 A) fuse in the under-dash fuse/relay box. If necessary, repair an open in the wire between the main relay and the STARTER SIGNAL fuse. Should the main relay and fuel pump still not work properly, go to Step 8.

8. Perform the K-Test on the ECM. Remove the MAP Sensor connector and turn the ignition switch ON (not start). Using a multi-meter, check for 5 volts going between the MAP Sensor connector's reference wire (+) and ground. As you look at the connector, this is the socket on the right. Really press the black test lead into a cleaned main ECM ground on the thermostat housing. If the voltage is low, it's probably indicating ECM failure. Most failed ECMs will record a fraction of a volt. To me, the K-Test is simple, elegant, and accurate. The ECM controls grounding to main relay Terminal 8, which affects when the second relay inside the main relay opens and closes. If the ECM cannot control grounding to the second relay, the fuel pump will not run. The only alternative is to replace the ECM.

SUMMARY OF MAIN RELAY PROBLEM AREAS:

Terminal 1--Test ECM fuse in under hood fuse box.
Terminal 2--Clean main ECM ground on thermostat housing.
Terminal 5--Test ACG (ALT) (S) fuse in under dash fuse box.
Terminal 6--Test STARTER SIGNAL fuse in under dash fuse box.
Terminal 7--Test continuity to fuel pump.
Terminal 8--Test ECM (K-Test).

Many hours of research, thought, and experience went into designing this easily understood approach to troubleshooting one of Honda's most complex systems. I consider this the most thorough coverage of this subject anywhere--it doesn't get any easier or better than this.

I would not be surprised if the ECM is intermittently failing, during wet weather. Most fuel-related problems on these cars are a function of bad fuses and/or ECM. If you replace the ECM, spray the A, B, and D connector pins with WD-40.

I experienced similar problem on 1994 Honda Accord. During rainy or humid conditions, car will not start. Engine cel stays on and fuel pump does not kick on. After leaving in key in the "on" position for a few minutes, fuel pump kicks on and cel light goes off, car starts right up.

Problem recently started getting worse. I removed ECM(no visual signs of moisture or rust), took off covers, dried with blow dryer, plugged back in and car started right up. Let car sit idle for an hour, tried to start again with no luck. Dried with blow dryer again and it started right up.

It is apparent ECM is faulty. Not ready to drop $300-$600 on replacement. So I have attempted to moisture proof ECM housing. Used silicon on covers and around outside of plug housing-being very careful not to get inside of plug housing. I am not sure of long term affects and if the ECM needs to breath or be vented. However, it is starting up with no problems now.

Update to above thread. As I feared, sealing up ECM has caused other issues. ECM is probably getting hot. I will be ordering replacement ECM in the morning.