fuel cut relay

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KPierson

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Joined: April 14, 2005

Location: Ohio, United States

Posted: May 09, 2007 at 6:10 AM / IP Logged

KarTuneMan wrote:

KPierson wrote:

I would recomend against method 2, as the relay will be energized whenever the car is off and the alarm is armed. This will put a ~200mA load on you battery at all time, roughly 4x the 'normal' acceptable load on a cars electrical system when not running.

You "open" the starter wire when you arm the car, you open the fuel pump control when you arm the alarm.... it's the same thing.... isn't it?

Every starter kill application I've installed the starter kill relay is NOT energized when you arm the car, but when you turn the ignition on while the alarm is armed. I think that that is important to point out here.

Kevin Pierson

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Joined: March 07, 2002

Location: Louisiana, United States

Posted: May 09, 2007 at 7:54 AM / IP Logged

KPierson wrote:

Agreed. Never connect a starter kill relay to constant 12 volts if the alarm is supplying a ground when armed.

fuel cut relay - Page 2 -- posted image.

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KPierson

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Joined: April 14, 2005

Location: Ohio, United States

Posted: May 09, 2007 at 11:06 AM / IP Logged

OK, I did some research to illustrate my point:

On my car, a 2004 Infiniti G35 coupe (twin turbo'd :) ) my stock battery is rated at 65a/h.

Say you add a relay that pulls 225mA and your car pulls 25mA in standby (reasonable values). With a brand new, fully charged battery, it will be dead in less then 11 days. Without the relay in the mix your brand new battery will hold a charge (theoretically) for 108 days.

As batteries age the a/h rating will drop, so these numbers will get smaller and smaller.

It's all a numbers game that can be calculated out with decent accuracy as long as you know the values of the given components (load and reserve capacity of battery).

Kevin Pierson

lagvoid

Member - Posts: 24

Joined: February 20, 2005

Posted: May 09, 2007 at 10:33 PM / IP Logged

So if the relay is energized, that small/slow steady draw will significantly reduce battery life...

Is there an alternative way to wire this relay without running it directly to 12v? I found this relay diagram to arm the alarm while a stand alone turbo timer counts down.

http://www.lagvoid.atotchat.org/240sx/tt.pdf

**I know the Viper 5900 comes with a built in turbo timer, but I already have a TT installed and I don't have to press anything to activate it.**

Eager for your replies! thanks

KPierson

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Joined: April 14, 2005

Location: Ohio, United States

Posted: May 10, 2007 at 5:52 AM / IP Logged

Yes, wire it up like 'relay 2' in the first post. You can't hotwire a car if the ignition isn't on, so use your igniton and (-) when armed output to control the relay. As soon as the ignition is turned on the fuel pump will be disabled, assuming the alarm is still armed.

Kevin Pierson

lagvoid

Member - Posts: 24

Joined: February 20, 2005

Posted: May 10, 2007 at 6:38 AM / IP Logged

Ok, things are starting to make sense now. Thank you all for the relays 101 lesson!

lagvoid

Member - Posts: 24

Joined: February 20, 2005

Posted: May 10, 2007 at 2:10 PM / IP Logged

The problem is not the tach learn or crank time, but the relay itself. The relay is being triggered (cutting fuel) during the remote start process. It runs perfectly fine when started with the key.

Fuel Cut Relay:

85 > orange from primary harness (ground when armed)

86 > BLACK/ red ignition

30 and 87a > fuel pump wire

Does the fuel pump wires being (-) change the way the relay works? Pin 85 is taking the ground from the fuel pump wires and kills the car. I'm really confused right now because it runs normal using the key. When I bypass the relay, the remote start works fine as well!

enice

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Joined: March 05, 2006

Location: New York, United States

Posted: May 10, 2007 at 2:24 PM / IP Logged

what you can do is bypass the relay with the (ground when running wire)....cut the orange wire and connect it to 30 and 87a. connect the blue wire from where the tach wire is to 85 and use 12v ign for 86

KPierson

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Joined: April 14, 2005

Location: Ohio, United States

Posted: May 10, 2007 at 2:26 PM / IP Logged

Does it remote start when the alarm is disarmed?

I almost seems like the relay is being energized during cranking because 1. your ignition is on AND 2. your alarm is armed. Try disarming the alarm and see if that helps.

If it does, you can use a 2nd relay to prevent this from happening by using the 2nd relay to make sure your first relay is killed whenever the car is remote started (using the (-) status out or a couple of other ways).

Kevin Pierson

lagvoid

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Joined: February 20, 2005

Posted: May 10, 2007 at 3:10 PM / IP Logged

enice wrote:

I'm sorry I don't get how this would work.

The manual shows the blue wire as, "supplies 200mA output as soon as the module begins the remote start process". Am I supposed to leave the fuel wires connected to 87a and 30?

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