Go Back   EcoModder Forum > EcoModding > DIY / How-to
Register Now
 Register Now
 

Reply  Post New Thread
 
Submit Tools LinkBack Thread Tools
Old 10-04-2010, 08:56 AM   This thread is in the EcoModder Project Library | #1 (permalink)
EcoModding Lurker
 
Join Date: Sep 2010
Location: Ovid MI
Posts: 45

Niner_xA - '05 Scion xA
90 day: 35.82 mpg (US)

Horse Hauler - '95 Ford F-250 XLT
90 day: 13.47 mpg (US)

Butterkup - '02 Mazda Miata
Thanks: 2
Thanked 8 Times in 5 Posts
Adding injector cutoff to a Scion xA

This directly applies to the 04/05 xA, but may work similarly with the '06 or gen 1 xB.

The fuse that protects the injectors in the xA also protects a lot of other things that I don't want to turn off when I kill the engine for EOC. Luckily, I found a very good wiring manual for the xA that traces the path of the wire from the ignition switch. There was a good location to find the wire I needed in a harness plug directly behind the glovebox. I wanted to just run a normally-closed switch across this wire, but couldn't find something rated high enough for my tastes at the local Radio Shack, so I went with a relay.

Button on front of shifter - one end goes to ground, one to the relay:


Behind the glovebox of the xA:


The appropriate connection - the injector power line is the black wire with the red stripe on the far right:


My small relay board - the always-hot side of the injector power goes on the bottom screw terminal, otherwise the relay will oscillate:


And... the day I installed this and used it, I got a CEL. My first guess is that it senses the injectors "failing", although the CEL was gone this morning and I did use EOC once. It's possible I underrated the relay I needed, so if the CEL comes back I'm going to get it decoded at the auto parts store. In case of relay failure, I have a crimping tool and some butt connectors in my car anyways.

Hopefully this helps someone else.

  Reply With Quote
The Following 4 Users Say Thank You to Niner For This Useful Post:
daring4 (03-25-2013), NeilBlanchard (10-04-2010), SentraSE-R (07-03-2011), Weather Spotter (10-14-2010)
Alt Today
Popular topics

Other popular topics in this forum...

   
Old 10-07-2010, 04:20 PM   #2 (permalink)
EcoModding Lurker
 
Join Date: Sep 2010
Location: Ovid MI
Posts: 45

Niner_xA - '05 Scion xA
90 day: 35.82 mpg (US)

Horse Hauler - '95 Ford F-250 XLT
90 day: 13.47 mpg (US)

Butterkup - '02 Mazda Miata
Thanks: 2
Thanked 8 Times in 5 Posts
And just like that, the CEL went off. I drove to & from work one day after posting this, and the next time I was in the car it was off. I've done plenty of EOC using the switch. Maybe it had to adjust to a slightly higher resistance (due to the "switch" in the relay)? Or the relay had to be "broken in" to get good contacts?

Works well in general, except for the one time I bumped it sitting at a stoplight with the engine warmed up. I idle at 500 RPM, so from there it's only a short drop to dead. Under normal speeds, tapping it just causes a little stutter in the engine.
  Reply With Quote
Old 07-03-2011, 11:20 PM   #3 (permalink)
Master EcoModder
 
Join Date: Jun 2010
Location: Australia
Posts: 253

Delivery 'Boy - '86 Suzuki Mighty Boy
90 day: 37.15 mpg (US)

SkipSwift - '13 Suzuki Swift GL
90 day: 35.44 mpg (US)
Thanks: 0
Thanked 53 Times in 42 Posts
It may have been because the ECU periodically measures the resistance across the injectors to see if they are electrically functioning. It certainly does this on other cars...

The technically correct method would be to switch in a resistor for each injector (or bank of injectors) when you want to do this (easily achieved with the right relay). However your method appears to work fine.
__________________







Quote:
Originally Posted by Crazyrabbit
In God we trust. All others: bring data
  Reply With Quote
Old 07-03-2011, 11:46 PM   #4 (permalink)
Pishtaco
 
SentraSE-R's Avatar
 
Join Date: Jun 2009
Location: Bay Area, California
Posts: 1,485

Mean Green Toaster Machine - '06 Scion xB
Team Toyota
90 day: 48.92 mpg (US)
Thanks: 56
Thanked 286 Times in 181 Posts
Niner, any updates on the CEL issue? Specifications for the relay? TIA.
__________________
Darrell

Boycotting Exxon since 1989, BP since 2010
Have you ever noticed that anybody driving slower than you is an idiot, and anyone going faster than you is a maniac? George Carlin
Mean Green Toaster Machine
49.5 mpg avg over 53,000 miles. 176% of '08 EPA
Best flat drive 94.5 mpg for 10.1 mi
Longest tank 1033 km (642 mi) on 10.56 gal = 60.8 mpg
  Reply With Quote
Old 08-09-2011, 09:44 AM   #5 (permalink)
Pishtaco
 
SentraSE-R's Avatar
 
Join Date: Jun 2009
Location: Bay Area, California
Posts: 1,485

Mean Green Toaster Machine - '06 Scion xB
Team Toyota
90 day: 48.92 mpg (US)
Thanks: 56
Thanked 286 Times in 181 Posts
I built my own kill switch following Niner's instructions, with some modifications and caveats. The wiring diagram for my '06 xB also shows a common red/black wire for my fuel injectors, so I started my build with the confidence that Niner had done my homework for me..

There are three black and red wires in the wiring bundle behind the glovebox. I didn't pay attention to detail, and cut the wrong wire the first time, and the second. Finally I paid attention to detail, and saw the wire Niner used is the one attached to the connector plug in his photo. I cut it, and the engine wouldn't run - confirming I'd located the correct wire.

I found a good relay web page, and designed my own wiring setup. I bought a Radio Shack 12V 10 amp single pole double throw relay and a 1N4004 switching rectifier, as well as a momentary pushbutton switch (normally open).

I ran +12V DC from the center pole of the cigarette lighter (a handy fused circuit) to one side of the pushbutton switch, and the other side to one of the contacts of the relay trigger circuit. I ran a ground wire from the side contact of the cigarette lighter to the other contact of the relay trigger circuit.

I wired my rectifier diode in parallel with the trigger circuit contacts, with the striped end of the diode to the positive wire coming from my pushbutton switch. This prevents inductive kickback or back EMF, from damaging the relay's contacts.

I wired the two ends of my cut common fuel injector red/black wire to the NC (normally closed) high voltage contacts of the relay. This is pretty fail-safe. When other parts of my circuit fail, the fuel injectors run normally.

While I was into the fuel injector circuit, I wired in a toggle switch for theft prevention. When I switch the toggle to open the circuit, the fuel injectors are disabled. Toggle the switch closed, and the car runs normally.

Push the pushbutton momentary switch for a second or two with the engine running, and the trigger circuit activates the relay's electromagnet, moving the contacts from the NC position to the NO (normally open) position, killing the engine. It does this without rebooting the ECU, traction control, airbags, and vehicle stability control systems.
__________________
Darrell

Boycotting Exxon since 1989, BP since 2010
Have you ever noticed that anybody driving slower than you is an idiot, and anyone going faster than you is a maniac? George Carlin
Mean Green Toaster Machine
49.5 mpg avg over 53,000 miles. 176% of '08 EPA
Best flat drive 94.5 mpg for 10.1 mi
Longest tank 1033 km (642 mi) on 10.56 gal = 60.8 mpg

Last edited by SentraSE-R; 08-12-2011 at 01:33 PM..
  Reply With Quote
The Following 2 Users Say Thank You to SentraSE-R For This Useful Post:
EchoBallin (01-03-2014), myrefugeisintheLord (01-08-2013)
Old 08-12-2011, 11:38 PM   #6 (permalink)
Pishtaco
 
SentraSE-R's Avatar
 
Join Date: Jun 2009
Location: Bay Area, California
Posts: 1,485

Mean Green Toaster Machine - '06 Scion xB
Team Toyota
90 day: 48.92 mpg (US)
Thanks: 56
Thanked 286 Times in 181 Posts
The new kill switch is working wonderfully. Using the key caused multiple misfire trouble codes P0300, P0301, P0302, P0303, P0304 when I turned the key on the first time each day . I theorized it's because the ECU saw 0 engine speed, but various vehicle speeds. Anyway, I haven't seen the problem since I installed the kill switch.

Now, instead of fiddling with the key, I press my button and a second later, I'm in a silent glide.
__________________
Darrell

Boycotting Exxon since 1989, BP since 2010
Have you ever noticed that anybody driving slower than you is an idiot, and anyone going faster than you is a maniac? George Carlin
Mean Green Toaster Machine
49.5 mpg avg over 53,000 miles. 176% of '08 EPA
Best flat drive 94.5 mpg for 10.1 mi
Longest tank 1033 km (642 mi) on 10.56 gal = 60.8 mpg

Last edited by SentraSE-R; 08-12-2011 at 11:52 PM..
  Reply With Quote
Old 03-27-2013, 10:02 PM   #7 (permalink)
Hyperlurker
 
daring4's Avatar
 
Join Date: Mar 2010
Location: Glendale, AZ
Posts: 87

D-max - '04 Chevy Silverado Ls

Notch - '65 Volkswagen 1500 S

MTCHBX - '05 Scion XB
90 day: 40.41 mpg (US)
Thanks: 12
Thanked 2 Times in 2 Posts
Using Niner and Sentra's experience's I finally installed my EOC switch. Radio shack parts were used; momentary switch #275-0644, relay #275-218. Power from the cig lighter energizes the relay. On my '05 XB a vacant switch panel on the dash above the ashtray was the perfect place to put the switch, after pushing into nuetral I can push the button with my index finger. I was confused that the scanguage turned off after the engine stoppped, reading the instructions again clued me into setting it in "hybrid" mode. Thanks again to you guys for finding the correct wire to cut, silent mode for this box!
  Reply With Quote
Old 03-27-2013, 10:31 PM   #8 (permalink)
Master EcoModder
 
Join Date: May 2012
Location: USA
Posts: 2,643
Thanks: 1,502
Thanked 279 Times in 229 Posts
Just 1 relay to 1 wire to kill the injectors? Id considered something like that for the insight, but we got 4 yellow/black wires and guessing 4 relays unless I want to do something fancy and make it a 2 cylinder.
  Reply With Quote
Old 03-31-2013, 05:33 PM   #9 (permalink)
Hyperlurker
 
daring4's Avatar
 
Join Date: Mar 2010
Location: Glendale, AZ
Posts: 87

D-max - '04 Chevy Silverado Ls

Notch - '65 Volkswagen 1500 S

MTCHBX - '05 Scion XB
90 day: 40.41 mpg (US)
Thanks: 12
Thanked 2 Times in 2 Posts
Quote:
Originally Posted by Cobb View Post
Just 1 relay to 1 wire to kill the injectors? Id considered something like that for the insight, but we got 4 yellow/black wires and guessing 4 relays unless I want to do something fancy and make it a 2 cylinder.
The Xb has four black/ red stripe wires if you splice closer to engine. You could use two relays to do four wires If you use a DPDT relay, I'm only using half of the one I bought, If it ever wears out I can use the other side

  Reply With Quote
Reply  Post New Thread


Thread Tools


Similar Threads
Thread Thread Starter Forum Replies Last Post
Scion xA aero mods NeilBlanchard Aerodynamics 521 04-20-2015 10:34 PM
New modder - Scion xA Niner Introductions 2 09-24-2010 07:06 PM
Scion XA in PA goodblues Introductions 25 08-27-2010 08:49 AM
Accessing front turn signals on Scion xA? NeilBlanchard Off-Topic Tech 1 04-14-2010 10:51 AM
Scion xA woes Ceyarrecks Introductions 10 01-12-2009 08:11 PM



Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Search Engine Friendly URLs by vBSEO 3.5.2
All content copyright EcoModder.com