Delay stereo turning on

[Gibbon]

Howdy

I would like to delay the stereo in the car turning on until after the engine is running.

At the moment, the stereo turns on when the key is turned to ACC - that's all good. But when cranking, there must be enough of a drop that the stereo resets itself. The stereo is supposed to remember what mode it was in when it was turned off.

I have the memory hooked straight to the battery ( fused ) - and the IGN wire to ACC.

Is there something that I can put between the IGN wire and the stereo to introduce a delay of about 10 seconds or so.

Google shows lots of delay circuits, but it seems you need to build them yourself.

Thanks.

[Flex]

Gibbon,

How will a delay help, cause your radio will still reset when you crank your engine even with a delay?

Flex

[Gibbon]

The theory being that the engine will be running before the stereo gets power from the IGN line.

Currently, the stereo is activating at the same time as the engine is cranking, and it seems that power is lost to the IGN line during that time. The stereo is one of those Chinese 7" slide out screen types. So it's part way through it's startup when the engine cranks.

Waiting until the stereo has finished it's thing before starting the engine only means the IGN line drops, the stereo does it's shutdown process, and then when the engine is running, IGN line has power again, and the stereo starts it's startup process again.

[Flex]

The ACC line is cars is switch off during cranking, that is why you are seeing you radio reset.

If you add a delay to the ACC line, then when you only switch to ACC on your key you will have wait 10s before your stereo will turn on.

[Gibbon]

Yup - that's what I was going for.

Wired a manual switch inline with the IGN line - works great now. I can leave the stereo turned off until the engine is running, and then switch it on - and there is no reset.

[Cuzzo]

Every other car it works fine.........

maybe theres a problem with your memory wire on cranking?

[Flex]

Do you still need the delay? I can suggest a circuit if you want...

[beerhead]

Try cleaning up all your grounds and battery feeds before you get carried away a timer circuit to make a delay. My bet is your main ground is corroded so under crank the voltage to the memory of the stereo goes to zero.

Extend your multi meter leads and run 1 from the negative terminal of the battery and the other to the negative under the dash that feeds the stereo. Put the meter in DC voltage mode and watch the screen as you crank, it'll tell you how many volts are being lost at crank over that wire. Do the same with that 12V constant wire, from the + terminal and you should be able to track down where the power loss is.

A quick fix might be to run a separate wire from the negative terminal on the battery directly to the stereo neg feed, that way the circuits are separate entities and won't effect each other.

[Gibbon]

Getting a drop from 12v to around 8-9v on the battery lead on cranking - which I'm guessing is enough for the stereo to think there is no power going to it - causing a reset.

[jondee86]

Pretty sure the ACC line is powered down during cranking. Seems to be
standard procedure on most cars.

Cheers... jondee86

[tojo]

Agree with beerhead - check grounds. The direct + should take care of memory , not the acc.

If the problem is still there after grounds are sorted you could try with a capacitor and diode in the direct + circuit