Sticking Double Relay

[chitwnvw]

If the key is turned off and/or the engine dies, the relay de-energizes and shuts off the pump.

If I understand the diagram correctly, when we switch from the start to the run key position, the power supply for the pump switches from one relay to the other.

[dtrumbo]

1. How do I permanently attach a wire to that white plug?

Me thinks it's a regular spade lug with a barb that sticks out to keep it in the white plastic socket. Try a small jeweler's screwdriver to gently depress the barb and then remove the spade. Solder the new wire to the spade and re-insert it in the plastic socket.

2. How did a loose ground give me these symptoms?

Bad grounds are eventually the cause of everything wrong with our vehicles. Accept it as the word of God and move on! Seriously, I suppose it might have something to do with the electro-magnetic field that energizes the relay not being able to dissipate or some such mumbo-jumbo.

3. Where's that AFM mixture adjustment guide?

http://itinerant-air-cooled.com/viewtopic.php?t=3665
Fifth post down.

If I understand the diagram correctly, when we switch from the start to the run key position, the power supply for the pump switches from one relay to the other.

That's not how I read it. When the key is turned to 'start', the voltage that goes to the starter solenoid also goes to energize the one half of the double relay that powers the fuel pump. Then when the key is released and the engine is running, the microswitch in the AFM continues to provide power to this half of the relay and the fuel pump continues to run. The other half of the relay (energized by the key in the 'on' position) provides power to the injectors, the ECU and to the microswitch in the AFM.

[Amskeptic]

If I understand the diagram correctly, when we switch from the start to the run key position, the power supply for the pump switches from one relay to the other.

(ahh no-editor)

That's not how I read it. When the key is turned to 'start', the voltage that goes to the starter solenoid also goes to energize the one half of the double relay that powers the fuel pump. Then when the key is released and the engine is running, the microswitch in the AFM continues to provide power to this relay and the fuel pump continues to run. .

(ahh yes-editor)

There are two relays in a double relay, this particular relay (the fuel pump relay) is energized either by starter or AFM. The other relay inside the double relay is the main relay that energizes the rest of the junk as necessary.
Colin

[chitwnvw]

Another instance of ratwell being wrong.

Can you explain the bizarre behavior being cause by the ground? The ground that kind of sort of worked?

At any rate the troutmobile is happy and now I have 2 extra DR's.

[Amskeptic]

Can you explain the bizarre behavior being cause by the ground? The ground that kind of sort of worked?

Interrupted ground paths can lead to weird "other paths to ground". These can energize circuits that are not supposed to be, or they can put voltage potential on both sides of an electrical consumer thus killing it, just like the alternator warning light goes out because both sides get 12 volts. A novice might do a voltage test on the alternator warning light, and conclude that it is supposed to light up because their test lamp sure does! The double relay has an important twist . . . there are two diodes to prevent electricity from "back feeding" when the relay coil is wired to two different sources. For example, when the engine is running and the AFM supplies electricity to the fuel pump's relay coil, that very same electricity could attempt to energize the starter solenoid. . . that would be "bad". The diode prevents electricity supplied from the AFM to back through the starter solenoid. The other diode prevents the one relay from feeding through the 85 ground path (particularly when someone forgets to secure that little brown wire to the firewall/mounting screw) up to the ignition coil via the main relay.
Colin

[chitwnvw]

So should I run a new wire to the coil also? Sounds like I should.

It's weird that the vehicle would start. Because it wouldn't without the ground wire attached to the firewall...unless the paths to ground appeared after the bus was started.