Ignition Power in Engine Bay

[belize1334]

I'm fiddling with my L2A setup and right now I'm hoping for a new power source for the water pump. I have been running it off of a relay up near the power steering pump. I've moved the pump so it now sits above the transmission so I'm hoping for a keyed power source in the main fuse box. If it is hefty I can pull straight from it. Otherwise I'll use it to fire a relay. I want it to be live any time the key is in the "On" position, regardless of whether the engine is actually running.

Suggestions on the best way to do this? Fan circuit? EFI circuit?

 

[toybreaker]

Rodger,

What's the current draw on the pump?

I think your safest bet would be to use an ignition feed to trigger a relay.

There's a couple of emission solenoids that are hot with the key over by the evap area that could be tapped for that purpose.

Just bring power over from the battery to power the relay, and you'll be good to go.

I would strongly suggest that you run an additional wire into the dash area to power up an led to show the system status

The easy way is to just tag it into the terminal 87 leg, and anytime that's powered up, the led will be on.

A more sophisticated led set-up would be to run a super bright red led that is only lit when the ignition is powered up and the pump is not powered up. (If you'd like, I can draw up a diagram showing how to do that.)

Might keep you from crushing the ring lands in the heat of battle if the pump goes tits up.

Good luck with the set-up, and post pics of the completed set-up.

 

[belize1334]

I don't think I want to get so detailed as to wire in an indicator light. The pump doesn't draw too much power and there shouldn't be any critical failure if it does die for some reason. I just need to find a good signal source, ideally at the fuse box so that I can use solenoids for other things, which I can use to trigger a relay for fused battery power.

 

[turboaddict]

I just ran a cable and fuse from the battery then put a switch in the passenger compartment. I only run the intercooler pump if I am boosting on it. just daily driving it is off. I have had the same pump since 2002. Still works fine. you are just wasting power and burning up the pump if you have it running all of the time.

 

[belize1334]

Yeah I've considered more advanced pump control setups. I agree that just driving around it's totally a waste to have it running. On the other hand, if you're pulling a 4% grade at 5 psi for 10 minutes, having the pump kick on automatically would be really nice. It'd also be nice to have a manual bypass so that you can let the pump run between autocross runs. Maybe a good solution would be to have to pump kick on any time the airflow goes above like 0.5 g/rev with a timer that keeps it on for say 10 minutes after dropping below that load value. The above logic could control a ground switch and then a second ground switch, in parallel, would come from the cabin as a manual bypass. Power would be fused straight from the positive terminal.

Oh, man... I'm liking this idea more and more. The only problem is that I'm running out of solenoids. I'm already hoping to use purge for my cyclone, fps for my dejon-mod bov, and now egr(?) or bcs(?) for water pump?

EDIT: Better yet... iirc the bcs solenoid is pwm compatible. You could run the water pump off of a pwm signal that goes to zero at low airflow and 100% at high airflow. Again, a 100% selectable bypass for autocross would be in order.

 

[belize1334]

So, this is actually turning out to be a bit of a pain. I've decided that what I want to do is have an ignition power circuit running at about 6v so that the pump defaults to low output any time the engine is on. Then I want a second, selectable power at 12v so that I can choose to force it to high output regardless. I've checked every fuse in the engine bay and they are all live all the time. I then checked the relays... they too are all live all the time. So, apparently the ignition activates certain relay signals but the power for those relays is always hot. Can anybody point me to an ignition signal on the passenger side of the bay that is only hot when the ignition is on?

 

[GVR4_1057]

The lower left wire in the 4 wire windshield wiper motor plug (looking from the back of the plug) is switched 12V.

 

[belize1334]

Awesome. I'll check that.