Where is O2 and Ground at ECU?

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Mar 10, 2003 | 06:54 PM

Blue_sooby1

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Where is O2 and Ground at ECU?

Please help the newby. Hopefully someone can help me out. I have a 03 WRX and purchased an APEX'i turbo timer. I have it hooked up except the diagram for the ECU doesn't cover anything past 98 or 99. To get the O2 and A/F sensors to work, I am supposed to splice the wires into the Cars O2 and ground at the ECU. Anybody know which wires I need to splice into? Right now the unit is just grounded to the frame and I left the O2 sensor wire detached. I still need to do the factory alarm/keyless bypass as well.

thanks for any help, Brian

Mar 10, 2003 | 07:27 PM

teiva-boy

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Joined: Nov 2002

Posts: 1,780

From: San Diego

Car Info: Boosted Geo Prizm

B17

Mar 10, 2003 | 10:00 PM

Blue_sooby1

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Cool thanks for the info. The instructions say to splice the ground into the the ECU as well but my ground should be fine where it is correct?

thanks, Brian

Mar 11, 2003 | 11:41 AM

keith

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I have the Apexi Timer and did not tap into the ECU ground and it works fine. I really like this timer.

Mar 11, 2003 | 03:46 PM

Blue_sooby1

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Cool, I like it so far too. It's nice and small. My auto timer isn't working but I am assuming that is because I don't have the O2 sensor hooked up yet.

Brian

Mar 15, 2003 | 12:31 PM

keith

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Yes, as soon as you tap into B17 your auto timer will work , tapping it wasn't as scarry as I thought it would be and grounding it to the car works fine. I like the digital air/fuel reading better than my Auto Meter Air/ Fuel gauge, this will work as soon as you tap B17. I was just using the manual mode at first like you, tap in your gonna like it more. More options for mounting with the sleek design, plus I like the toggle button.

Mar 15, 2003 | 04:52 PM

240sxer

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Joined: Jan 2003

Posts: 513

From: southern california

Car Info: 98 L w/hybrid ej257 Linked

my friend bought one, for a MR2... any tips? on installing we have no idea how... we have a harness and everything. after we plug it up to the ignition... should it turn on? also what is that wiring going to the ebrake for...

Mar 16, 2003 | 11:07 AM

keith

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Plug the harness in and tap into your parking brake wire, brake must be engaged for the timer to work, when you release the brake it shuts the timer off. All the timers I know must be wired to the parking brake. Also you need to ground the black wire. Your timer will now work in manual mode, but you need to tap the o2 sensor wire for the auto-timer and A/F reading.

Mar 16, 2003 | 08:37 PM

240sxer

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Joined: Jan 2003

Posts: 513

From: southern california

Car Info: 98 L w/hybrid ej257 Linked

where did you ground the wire to?

Last edited by 240sxer; Mar 16, 2003 at 08:46 PM.

Sep 13, 2003 | 08:05 PM

#10

NewShockerGuy

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Posts: 660

From: PA

Car Info: TXS tbe, perrin goodies, v7 sti struts...bla bla bla lots of stuff!

I grounded mine into the chasis... Reason being I tapped into the B-17 wire and B-19 wire on my ECU and this is not correct! I have an 03' Rex... the ground on the ECU does not turn the unit on... As soon as I took the wire off of the ground on the ECU and touched it to the chasis it turned on.. NOW my problem is the A/F and the o2! The A/F feature is saying 20 and the o2 does not leave 0.01 or 0.02... What is going on???

I love this little thing and if it would work I would be sooooo happy!

If anyone can help me out it would be great!

Thanks,
-Nigel