NGK AFX install: why does it say 12v power should use switch/relay?

[Rice Over Wheat]

I don't see why this makes a difference instead of just connecting the power wire to any 12v source directly.

The instructions say:

Supplying power and ground through a vehicle's cigarette lighter is not recommended. The power terminal should have 11 ~ 28V DC attached (via a switch or relay) whenever the engine is running. If the sensor is not powered when the engine is running, sensor life will be shortened. The AFX (including sensor) draws less than 2 amps.

I'm guessing NGK is just being overly cautious with its instructions. Are they saying it's harmful to have the sensor connected direct to a power source where it can be powered on with the ignition to ON?

 

[tom04841]

They are saying to have it wired into a 12 volt source that is only on with the key in the on position (switched power)....not hook it up to a switch

 

[Rice Over Wheat]

That's what I thought, which is why I don't get why they "don't recommend" using the cig lighter for a power source.

 

[snox135]

On some cars (not sure about DSM's) the cig lighter is powered all the time.

 

[Rice Over Wheat]

Ah I see, I don't believe ours are. that's what powers my radar detector which is only on when the ignition is ON.

I'll be wireing it to the cig lighter then.

 

[PRESSURIZED]

Ah I see, I don't believe ours are. that's what powers my radar detector which is only on when the ignition is ON.

I'll be wireing it to the cig lighter then.

Dont hook the wideband, Radar detector AND the Cig to the same little ass wire..what are you thinking?

 

[Rice Over Wheat]

The cigarette lighter is never used, the radar doesn't draw much amps, and the wideband just two. I don't see the big deal.

 

[tom04841]

Best place to tap power is right at the ecu.

 

[Rice Over Wheat]

Well I'm not going to use the lighter since I used that for my RMT manumatic 12v source. Right now the hardest thing is finding a good place to mount the wideband. Unless you want an ugly cable in plain sight, it's tough finding a really clean place to mount it. That's what is holding me off now as I try and figure out a solution. No wonder people go with the gauges.

 

[alex99gst]

Well I'm not going to use the lighter since I used that for my RMT manumatic 12v source. Right now the hardest thing is finding a good place to mount the wideband. Unless you want an ugly cable in plain sight, it's tough finding a really clean place to mount it. That's what is holding me off now as I try and figure out a solution. No wonder people go with the gauges.

I bought one of those A/C vent mounts for a gauge and it had a slot for something else. I was going to trim it up so that the AFX fit in there too, but now my car doesn't even run.

 

[Rice Over Wheat]

Heh, the life of a dsm owner. It's always something. I'm STILL looking for a good place to mount this thing. I have one slot cut into my center console to the right of the lighter, but it would require more trimming and a bracket or something behind it to rest on. I think I may just let it hand out on the passenger seat while I figure it out.

 

[spectr019]

If you find a spot, let me know!!! I have a s-afc II ontop of the dash, radar detector above that, few things below that...I'm feeling kinda crowded, and I need a place to mount it!

Ben

 

[eclipsegsx1736]

I have mine up on the dash under the a-pillar area. That way it's easy to see without having to look away from the road. It's not too bright at night time (especially for us who are used to plenty of gauges etc shining in our eyes). I used the red power wire for the ECU, pin 25 I believe, then I used the baro input to log the WB in dsmlink (if you still have a MAS, you can use the rear o2 input or MAP with dsmlink).

 

[Rice Over Wheat]

I have mine up on the dash under the a-pillar area. That way it's easy to see without having to look away from the road. It's not too bright at night time (especially for us who are used to plenty of gauges etc shining in our eyes). I used the red power wire for the ECU, pin 25 I believe, then I used the baro input to log the WB in dsmlink (if you still have a MAS, you can use the rear o2 input or MAP with dsmlink).

Where did you route your wires at that spot? I also considered it but I don't want the harness running down the side. I thought about pulling that tweeter cover and seeing if I could stuff the cable down there...doubt it.

 

[eclipsegsx1736]

Yeah, I ran the wires down thru the door sill. Probably not what you're looking for, my car is pretty mickey moused as far as wiring goes but it works so whatever. Interesting idea with the tweeters though. So who's gonna make a bluetooth wideband controller?

 

[Rice Over Wheat]

I decided to mount the same spot. I ran the cable probably the same way you did, with the power/ground hidden inside the trim. It actually looks pretty good. But my AFX wasn't powering on when I tapped my meth pump's power wire, so I ran it direct to the battery for now to calibrate, then disconnected the cable until I figure out how to put a relay/switch in there or whatever to make it only power on with the engine running. Any idea how to do that? I'm weak on electronics knowledge.

 

[eclipsegsx1736]

You must be logged in to view this image or video.

You can use pin 25 on the ECU to power the AFX. For the ground, the bolt that secures the ECU to the chassis worked for me. This way, the AFX will power on and off with the ECU.

 

[Rice Over Wheat]

I didn't use the ecu wire because I didn't like how small the gauge was. The first time I tapped my power wire to my meth pump but it never powered on -- I just remembered why: it's got a boost switch and circuit doesnt close until over 10psi, duh... The lighter is a no-go since I already tapped that with my manumatic. Well damn, I guess I may have to tap the ecu power.

 

[eclipsegsx1736]

It's decently thick and NGK says the AFX only uses 2 amps which isn't much.

 

[Rice Over Wheat]

Well I tapped pin 25 and no power to the AFX. I don't get it. It powered up fine directly off the battery, but everytime I tap into an existing line I don't get anything. I'm going to have to figure it out tomorrow.

 

[snox135]

Pin 75 or pin 25?

 

[eclipsegsx1736]

Pin 25 is found on the largest of the connectors that plug into the ECU. It is a relatively thick red wire, and recieves power along with the ECU, so it will turn on when the key is turned to ON position.

 

[Rice Over Wheat]

Yeah I meant 25 power, I tapped 75 for the O2 narrowband output in dsmlink. I used one of those quick splice fasteners and the AFX isn't powering up but the ecu is fine. I'm going to just do it the old fashioned way tomorrow and tap directly. Those quick splice things suck ass.

 

[eclipsegsx1736]

Yeah...Those vampire connectors can be iffy. How did you attach the ground wire for the AFX? I hooked both the main power ground and the signal output ground to the bolt that holds the ECU in place.

 

[Rice Over Wheat]

I did the same with the ground. Got my AFX working fine now, tapped the old fashion way into the ecu power wire. I lengthened it by a good foot so everything else I need power for will be easier to tap.