Jump to content
SAU Community

Accidentally Shorted Battery

MP_R33

By MP_R33,
in Engines & Forced Induction

 Share

Recommended Posts

Badgaz Experienced

Badgaz

Posted
Posted

Well, the discussion had gone through the points of shorting the battery not mattering (to the ECU) and why welding could be a bad thing. As such, the concept of 12v being the killer was no longer pertinent (at least to this discussion).

Yeah i think i'm saying no shit because you don't think i could possibly understand that a welder puts out a lot of voltage....sorry thats the way you came across to me.

jiffo Mentor

jiffo

Posted
Posted

When a workshop welds on your car's exhaust etc, they fit a surge protection device across the battery terminals.

These days everything is DC so you never hear of alternator diodes cooking, was very common back in the AC welder days.

I'm yet to receive an iron clad guarantee from any workshop that if they blow my ecu they'll replace it.

So I unplug mine.

GTSBoy Grand Master

GTSBoy

Posted
Posted

Yeah i think i'm saying no shit because you don't think i could possibly understand that a welder puts out a lot of voltage....sorry thats the way you came across to me.

No I was just thinking that you'd skipped over the fact that we were talking about welders by that time.

westom Newbie

westom

Posted
Posted

So it's impossible to damage the ECU then by shooting the battery.

True as long as the engine is not running. Any changes to battery connections (including that tool generated short circuit) when the engine is running can create load dump whiich has been defined by ISO and SAE to be as much as 270 volts. Latest numbers have lowered that to (if I remember) something just under 100 volts.

Automotive electronics therefore also meet higher voltage requirements. For example, 5 volt regulators must withstand something like 60 volts without damage.

Never make electrical changes (not including a jump start) if an engine is running.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing


  • Similar Content

  • Latest Posts

    • GTSBoy
      New kid on the block

      By GTSBoy · Posted

      The wiring diagram for the R33 RB25 is freely available, and is essentially the same same as most other RBs (just with differences as to which pin # does which job). To get the ECU to power up, you just need to provide power to the ECCS relay, and have the other power feeds that come in from the top left of the wiring diagram (wrt the ECU) that give perma power to the fuel pump relay, the ECU itself, etc etc, all connected. When you put power on all these it will just come to life. It's pretty clear from the diagram what needs to happen. Just follow the lines from the 12V + supply stuff in the top left over towards the ECU. I've even posted snips of such diagrams (not for vanilla 25, I think for Neo and 26) to various threads here in the last few months, talking about what it takes to get the fuel pump and FPCM up and going. Search these up and they will help get you started on doing the same with the vanilla 25 diagram. Hell, for all I know, I've done the same with that one in years past and have forgotten.
    • Duncan
      New kid on the block

      By Duncan · Posted

      Yep...so unless someone posts up the answer you will need to probe from the ECU connector to the dash plug with a multi meter in continuity mode to trace the wires.  Note the ECU has multiple - and + (and across different key settings - Battery, IGN and Start) and most likely the power is fed from the connector(s) that is normally near the left hand headlight.
    • Songo
      New kid on the block

      By Songo · Posted

      Thanks Duncan, I am actually just trying to get the Rb turning and running with the RB25DET S2 original loom itself  I am just trying to get it going outside the body and not thinking about the S15 or trying to match anything to the S15 loom at all I am only trying to see if anyone has done this and what pin they found to be the ignition trigger and ECU+/- on the dash connector, that's about it. Thanks  
    • iain_ST44GA
      M35 VQ25DET starter motor

      By iain_ST44GA · Posted

      Hi Guys, Does anyone know any aftermarket part numbers for a starter motor to suit the VQ25DET? I can find lots of alternative part number for the VQ35DE, which I assume would fit, but there is a lot of conflicting information out there. Thanks..
    • Murray_Calavera
      R33 GTR running -9 with no tune

      By Murray_Calavera · Posted

      I don't understand how this hasn't boiled down to - Upgrade the turbo when you have everything required. ECU, injectors, fuel pump, turbo, etc. Do it all at once.  If you don't have everything required, just enjoy the car as it is and keep saving up your pennies. 
×
×
  • Create New...