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Normal for stereo to restart when car started?

Discussion in 'Motors' started by Gigabit, May 25, 2017.

  1. Gigabit

    Mobster

    Joined: Apr 9, 2012

    Posts: 11,776

    Is it normal for an aftermarket stereo to turn off and then back on again when the car is started, after having the key previously in the ACC position?
     
  2. bremen1874

    Capodecina

    Joined: Oct 20, 2008

    Posts: 10,559

    If it's wired correctly with regards to permanent and switched lives it should behave the same as the OEM stereo.
     
  3. Shivy011

    Soldato

    Joined: Oct 26, 2013

    Posts: 7,672

    Location: Leicester/Loughborough

    I have an aftermarket stereo and it behaves differently to OEM - it does turn off and on again if the ignition was on
     
  4. Stormster

    Mobster

    Joined: Oct 18, 2002

    Posts: 4,672

    Location: Stoke-on-Trent

    Pull it out and if it has red to red and yellow to yellow wires into bullet connectors on the ISO loom, swap them round :)
     
  5. sovietspybob

    Mobster

    Joined: May 25, 2008

    Posts: 2,536

    Location: North Wales

    My OEM stereo does this in my Avensis so could just be how it's wired. Otherwise as said most aftermarket stereos allow you to change some of the power connections with bullet connectors.
     
  6. Howard

    Capodecina

    Joined: Jul 12, 2007

    Posts: 15,788

    Location: South East

    It's nothing to do with the power connectors. It's just the fact that the starter motor is consuming the majority of the battery's power for those couple of seconds, therefore things like the stereo will momentarily power off. It's often 'better' for warm starts.
     
  7. Django x2

    Capodecina

    Joined: Sep 28, 2008

    Posts: 12,482

    Location: Britain

    Some shoddy old cars like Howard suggests will do this as the engine cranks. I assume here you're not talking about it resetting back to odd settings upon engine start?
     
  8. Phemo

    Soldato

    Joined: May 6, 2004

    Posts: 5,372

    Location: Portsmouth

    Mine will do this if the key has been in without the engine running (equivalent of position 1) and the stereo has been on for quite a while, like a minute or so. If I pop the key in and fire the engine up within that sort of time then it won't restart though.
     
  9. Jamesyboyjim

    Mobster

    Joined: Oct 30, 2008

    Posts: 3,021

    Location: South

    My car does this, the standard stereo did too. I just assumed it cuts off so the engine can have all the power to start.
     
  10. Dogbreath

    Capodecina

    Joined: Oct 18, 2002

    Posts: 16,639

    Location: Devon

    Nothing to do with the car being shoddy and old.
     
  11. Glanza

    Sgarrista

    Joined: Mar 13, 2007

    Posts: 9,944

    Location: South Yorkshire

    This.
     
  12. Django x2

    Capodecina

    Joined: Sep 28, 2008

    Posts: 12,482

    Location: Britain

    Well, it is, as none of my cars since about 2005 have done this.
     
  13. Conscript

    Sgarrista

    Joined: Oct 18, 2004

    Posts: 9,180

    Location: Kent

    Both my 2013 cars do.
    So it's not just old cars. I wouldn't personally say that leaves ruling my cars as "shoddy" either, but I guess that's subjective.
     
  14. Rroff

    Man of Honour

    Joined: Oct 13, 2006

    Posts: 64,644

    Fairly normal behaviour unless there is some kind of power management with capacitors or something to ensure uninterrupted supply while the battery is supplying into what is essentially a short (the initial inrush current can be very high for a starter) with the starter.

    It won't be so much shoddy old cars as how much the manufacturer has been cheap or not - even some quite old cars have electronics to offset this behaviour.
     
  15. adolf hamster

    Soldato

    Joined: Oct 18, 2012

    Posts: 7,006

    if your sig is in any way representative of what you drive then i think that's a solid conclusion.

    tbh as others have said i'd have assumed the vast majority of card would do this, although more modern cars may well be more likely to have the countermeasures.

    starter motor takes a massive amount of power- if you've ever accidentally started a car whilst in gear you'll know what i mean.
     
  16. Nasher

    Capodecina

    Joined: Nov 22, 2006

    Posts: 14,211

    The starter will be drawing almost all of the available power. If it's a basic radio it might stay on but not a satnav one, which is basically a small PC.
     
  17. Rroff

    Man of Honour

    Joined: Oct 13, 2006

    Posts: 64,644

    Looking around it seems someone might have patented (in a vehicle context) the most intrinsic way of managing the situation :( can't see how that would stand as its fairly fundamental electronics which might be why some cars handle it better than others (also some devices will be better able to withstand momentary loss of power than others - wouldn't surprise me if some mainstream consumer devices they've omitted smoothing capacitors, etc. to save money).
     
  18. Liquidfox

    Mobster

    Joined: Sep 26, 2007

    Posts: 3,990

    Location: Newcastle

    In my Focus the aftermarket unit would lose power for a split second whilst the engine started so I'd have to wait an age for everything to connect again. No such issue in the new car though :D
     
  19. Gigabit

    Mobster

    Joined: Apr 9, 2012

    Posts: 11,776

    I swapped the cables and the same thing happens. The cigarette lighter power also goes off so I'm assuming it's just a normal feature of the Mazda2.
     
  20. Lopéz

    Man of Honour

    Joined: Oct 17, 2002

    Posts: 27,142

    Location: Leicestershire

    All sorts of cars do this, new and old