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Question Aux Air Reg - Voltage prob

I've been having sporatic results using the stock Aux Air Reg (AAR) on my 2.0L. Since winter is back in AZ, I've tested, rewired, and remounted the AAR for use.

The AAR itself works fine stand-alone or mounted and closes with 12v directly from the batt.

Here's my problem: I'm getting voltage dropout from the 12v lead to the regulator. I repaired what intially was a broken wire, but the source voltage is dropping out somewhere. I checked impedence across the wire from the relay board and its OK.

After reviewing the manuals I've arrived at some questions:

1) The AAR voltage comes from lead #12 of the relay connector at low-right of board. Is this power source a constant (switched) 12V?

2) My schematic for the relay board shows lead #12 going to lead #87 of the Fuel Pump relay & to lead #13 (which I thought was UnSwitched pwr). Does the relay play a roll in this circuit?

3) Is there a problem if I rewire the AAR to get 12V (switched pwr) at all times, or does it have to cut off at some point?

Many thanks,
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Old 02-05-2007, 04:43 PM
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The AAR gets its power from the fuel pump circuit. Any time the pump is on, the AAR gets power. The pump is powered by the fuel pump relay, so therefore the AAR is as well.

You could switch the wiring around so that the AAR is powered by some other switched power source. That should not be a problem, but I would prefer to have the switching done by some relay rather than having the extra current (1 amp or more!) going through the ignition switch. I also don't like hooking extra stuff onto the coil, which I feel needs all the juice it can get--particularly if you've got an electronic ignition hanging off of it, like I do...

--DD
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Old 02-05-2007, 06:07 PM
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Dave,

So does that mean I have a problem with the FP relay? I'm using MegaSquirt & have the FP wired off its relay rather than the stock - so I wouldn't notice if the relay was bad. Isn't there a way to jumper the pins (socket) of the relay to by-pass it?

TIA,
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Old 02-05-2007, 06:15 PM
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Since you're not using the fuel pump relay to run the pump, I would say that a bad relay (or something bad in the circuit) is a definite suspect. You can wire things so the relay is always on, engine on or off, but that's not what you want. I believe that you can ground one of the wires on the four-pin connector on the relay board and have the FP relay go on any time you send power to the ignition. Unless that's also been changed out?

In the stock D-jet setup, the ECU is what runs the fuel pump. It grounds pin #3 of the four-pin connector (that's the left-front pin) to turn on the pump. If you wire that pin directly to ground, the pump relay will be controlled by the "power supply relay" (the next one forward on the relay board) which gets turned on when the key goes to "on" and power gets sent to the coil.

--DD
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Old 02-05-2007, 11:39 PM
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Dave,

Good info - thanks. I finally dug out my data on the MS relay board and what I had done. Since I have the FP tied to the MS relay board, I removed the stock FP relay - Duh! - thereby disabling the circuit for the AAR.

I wasn't using the Aux Air feature on the MS relay board so I just used that. In fact I had it already wired to the engine bay but terminated. I was thinking ahead when I did that - but unfortunately I forgot that I did.

Am I gettin older or what?

Enjoy!
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Old 02-07-2007, 03:18 PM
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