Need to find acc wire that stays alive during crank.

Bobby Digital · 01-29-2004, 07:00 PM

I'm using a Jeff Mucha shutdown controller and for the "aux" wire I'm going to use the accessory switch wire which goes to my headunit but this wire does not stay alive during cranking. I'm assuming this would cause my system to shutdown when I crank. I don't know where I could find an accessory wire that would stay hot during crank. What is the solution for this?

Upon taking apart the steering column I can see that there are six wires plugged into the ignition barrel thing, but I don't know what any of them are and I don't have a multimeter, I only have a circuit tester so I can only test to see if the wire is hot or not.

MatrixPC · 01-29-2004, 07:05 PM

here you go
http://www.mp3car.com/vbulletin/power-supplies/21179-accessory-line-delay-circuit-any-ideas.html

wizardPC · 01-29-2004, 07:05 PM

www.bulldogsecurity.com

R3l0ad · 01-29-2004, 07:05 PM

Not going to happen......

for tank circuits

surving cranks!! Your going to need to build like a tank circuit or buy an OPUS that is the only way to survive a crank!!!

Bobby Digital · 01-29-2004, 07:09 PM

Quote: Originally Posted by R3l0ad

Not going to happen......

for tank circuits

surving cranks!! Your going to need to build like a tank circuit or buy an OPUS that is the only way to survive a crank!!!

Umm, I will have a tank in place, but if my accessory wire goes low then it will tell the shutdown controller to send an atx pulse to turn the computer off. Thus my computer will shut down during crank, not due to a loss of voltage but due to the shutdown controller losing +12V on the "aux" line.

robiewp · 01-29-2004, 07:23 PM

IGN (ignition) found at the ignition harness. On when the car's on, off when the car's off. through cranking and whatnot.

only use this for switching a relay!

Bobby Digital · 01-29-2004, 07:27 PM

Quote: Originally Posted by robiewp

IGN (ignition) found at the ignition harness. On when the car's on, off when the car's off. through cranking and whatnot.

only use this for switching a relay!

How about for switching a shutdown controller, is that acceptable use? And can you specify more where this can be found exactly?

MatrixPC · 01-29-2004, 07:33 PM

Read the thread on the link I posted earlier. Combine the ACC and IGN wire together. That will do the trick.

robiewp · 01-29-2004, 08:47 PM

BALLS! i misspoke. the IGN wire is not on all of the time, only when the engine is.

Matrix, in my car the ACC switches off before the IGN switches on. if you turn the key fast were talking sub 50ms, but there's a state where the key has turned off accessory but not turned on IGN, and depending on how slow you turn the key could be long enough to cause a problem. I know it would trip a simple relay. How do you counter this?

ncamara · 01-30-2004, 05:21 AM

How about running a wire from the battery?

MatrixPC · 01-30-2004, 10:45 AM

Quote: Originally Posted by robiewp

BALLS! i misspoke. the IGN wire is not on all of the time, only when the engine is.

Matrix, in my car the ACC switches off before the IGN switches on. if you turn the key fast were talking sub 50ms, but there's a state where the key has turned off accessory but not turned on IGN, and depending on how slow you turn the key could be long enough to cause a problem. I know it would trip a simple relay. How do you counter this?

You mean the ACC wire is cut off when switch from ACC to IGN?
That is odd. Well that could be for some American cars/Eupopean cars that I don't know of.

audrenaline · 01-30-2004, 01:17 PM

Just delay the shutdown controller for a few seconds before it sends the ATX power pulse (R1 on the MPEGBOX SDC). If the IGN line goes low while cranking but turns back on after cranking the shutdown controller won't send the pulse to shutdown the computer.

Ricky327 · 01-30-2004, 01:27 PM

You mean the ACC wire is cut off when switch from ACC to IGN?

I thought the ACC turn off then you crank the engine...it does stay on when the key is on the IGN, the normal position when driving the car.

This is what I know :

ALL OFF > ACC ON > ACC ON and IGN ON > ACC OFF, IGN ON and STARTER ON.

You need to have your IGN on while cranking and during driving, engine wont start without Ignition, hence the name IGN

ACC can go off during cranking as this is only for radios and such...not required to start your engine.

But of course some cars are different, but it should be fairly standard

NJay · 01-30-2004, 03:16 PM

I think what robiewp is saying is that if he turns the key to midway between the ACC and IGN points neither are active on his car and hence joined dioded arrangement won't work MatrixPC suggested won't work as that relies on at least one being active.

Bobby Digital · 01-30-2004, 06:28 PM

Quote: Originally Posted by audrenaline

Just delay the shutdown controller for a few seconds before it sends the ATX power pulse (R1 on the MPEGBOX SDC). If the IGN line goes low while cranking but turns back on after cranking the shutdown controller won't send the pulse to shutdown the computer.

Good thought, but I have modified the shutdown controller to also send an atx pulse when the aux line goes high (thus it is now a startup and shutdown controller). See this thread for how.

So, even if I delay the shutdown atx pulse, a startup atx pulse will be sent once I stop cranking and the accessory line goes high again.