w/ACC on, Fuel Pump and Fans on full

[drcustom]

Normally when you put the key to the accessory position the fuel pump turns on for 3 seconds or so, then shuts off...this is running constantly.

Additionally, both fans are on full high. Disconnecting the plug at the temp sensor in the thermostat housing doesn't change anything, and the wires at the plug don't look to be broken or in contact with each other.

Last night I started the car and let it warm up (no fans and fuel pump did not stay running beforehand). The fans kicked on before the engine warmed up, maybe after a couple of minutes. I didn't think much of it until today - both fans are on full and the engine is cold.

I'm fairly certain the car thinks it's running hot for some reason so I haven't tried starting yet...but I've never seen this issue before with the fuel pump constantly running.

[XakEp]

DSMlink will let you have them set to turn on full when the key is forward.

[drcustom]

DSMlink will let you have them set to turn on full when the key is forward.

That's good to know it can be modified somehow...but also concerning me that maybe that circuit on the ECU is messed up.

What about the fuel pump running constantly? If it was just the fans I'd be looking for bad wires or sensor, but the fuel pump is making me think there's more to this.

[matthewdesigns]

What about the fuel pump running constantly? If it was just the fans I'd be looking for bad wires or sensor, but the fuel pump is making me think there's more to this.

Could this be related to the issue you ran into with the alarm/no cranking? Are car alarms elaborate enough to include fuel pump defeat circuitry? Perhaps something there is still interfering if so.

[drcustom]

Could this be related to the issue you ran into with the alarm/no cranking? Are car alarms elaborate enough to include fuel pump defeat circuitry? Perhaps something there is still interfering if so.

It sounds like you're saying this could be two separate problems...and it could be even though they showed up at the same time. I'm going to see if I can find another temp sensor, but I thought if disconnected the ECU would interpreted that as cold, not hot...I'll see if the wires are shoted.

It was a while since I had worked on the electronics...I took out a Greddy Spec V, Turbo Timer, and an add-on module for the alarm...I was mistaken and had not taken out the alarm, but did find that a relay was missing. As soon as the relay was reinstalled it cranked normally.

I have heard of a fuel pump cutout, but usually that would only allow power to go to the fuel pump when the car wanted to fuel pump to run...not keep it on all the time (but then again, who knows how this could have been wired).

Once I got the car to crank, I took out the plugs and disconected the injecors and cranked a few times to get some oil circulating with no load. During that time, the fans were not on. I'd guess the key sat in the ACC position for 10-15 minutes when I wasn't cranking, and the fans were not on then.

A few minutes later I started the car and let it warm up. At some point I heard the fans come on (this was the first time I had heard the fans come on)...but noticed the gauge showed it wasn't completely warmed up. I turned it off shortly after that, and tried to start again the next day - that's when I noticed the fans were on when cold.

[drcustom]

strange...

I had another temp sensor lying around so I plugged it in (not installed). Turned the key - fans blipped on for less than a second, and they were off - no fuel pump running.

Still no idea why the fuel pump has anything to do with this, but...I think this was the sensor dying and maybe the ECU stores the last known reading when it failed as a 'better safe than sorry' approach?

Either way, when I plugged the old sensor back in, no fans.