2d system on 94 RX-7: pump running continuously?

[scl]

Hello all,

I'm new to WI. I searched, but couldn't find anything on this topic. I purchased a single turbo '94 RX-7 w/ a new 2d system already installed in the rear hatch.

With power switched on, the pump comes on and will not stop until I turn the power off. Fuses are ok. I have primed the pump and verified that at 10 psi there is a nice atomized spray from the injector. I let the pump run for a couple of minutes to remove any air in the system. I spoke w/ the installer of the system and this was not a problem for the 1500 miles he put on the car after installation. The WI was not used for a period of months prior to my purchase of the car. The LEDs on the FIA2 appear to be ok. I don't see any major leaks in the system. A few drops of water are present on the HSV at the junction of the metal body of the valve and the wires.

The system works well, but right now I must turn the system on and off manually whenever I decide to drive the car with "spirit" to avoid damage to the pump. It gets very warm to the touch after its on for longer than a few minutes. HELP!

Stew

[Greenv8s]

I'm no expert, but I think that system uses a pressure switch to control the manifold pressure? The switch goes open circuit to turn the pump on, so any electrical fault in the switch or associated wiring would cause the pump to run continuously. I guess it's also possible that the pressure switch has simply been adjusted too high.

[scl]

I'll check on the setting of the water pressure switch. The manifold pressure switch seems to be functioning, as 10psi of pressure applied to it causes the injector to spray.

[Greenv8s]

Don't you have two pressure switches? A 10 bar one on the water manifold (which is the one I was talking about) and a separate one connected to the engine intake manifold to enable the controller (which I guess you are talking about).

[scl]

Yes, two switches. I thought you were talking about the pressure switch reading the engine manifold pressure. This one seems fine. I'm not sure about the 10 bar switch on the water manifold. Maybe this is the culprit! I'll check it out later and post my findings.

thanks,
Stew

[scl]

Well, I checked the water manifold pressure switch (next to the pump) and discovered that a grey wire from the loom has broken free of the switch. There is one black wire and one grey wire connected to the water pressure switch. Based on the wiring diagram, the broken grey wire needs to be soldered back onto the water pressure switch at the site of the existing grey wire. Does this sound correct? It seems as though this should fix the problem, as believe this means the pressure switch has been deactivated due to the disconnected grey wire. Thoughts?

Thanks,
Stew

[Greenv8s]

Sounds reasonable. Check the wiring diagram to make sure, but if you can see where the break occured then it's very likely that you just need to reconnect that wire.

[scl]

BINGO!!!

Re-soldering the grey wire onto the water manifold pressure switch did the trick. The pump came on briefly to prime the system, and then shut off as it should. I'll test the system tomorrow to ensure all is well.

Thanks again for the help!

Stew