Starter Solenoid/relay Weirdness

[ScoobyJawa 23]

Hi all

 

I've had the ongoing common issue of the click syndrome when starting the car, usually caused by the starter motor solenoid wire from the ignition. Well good news is I've definately proved it is the wire!

 

Instead of running a new wire all the way to the ignition I fitted a 4 way relay to get a really good feed direct from the battery. Starts a treat now but theres a problem - car fires up on the second point on the ignition, not when you turn to start!! Not only that but the starter never stops running either.

 

Have I got a faulty relay or have I done something stupid?

 

Basically I've wired as per the following:

 

30 - constant 12v (direct to the battery with inline fuse)

87 - switched power (goes off to the solenoid so is joined to 30 when relay is powered)

85 - ground (to earth point on passenger wing)

86 - relay power (the original solenoid wire)

 

I believe thats correct and should work only when I turn ignition to start point, but as mentioned it fires the car on second ignition position and doesn't deactivate.

 

Many pointers - other than just running a wire to the ignition?

Thanks

Neil

Edited November 11, 2012 by ScoobyJawa

[ablister 31]

sounds like pin 87 is connected to an ignition live feed rather than crank feed, you can confirm with a multimeter by seeing if it gets 12v with ignition on. Nothing to do with the relay

[Anthony 1,003]

I had this issue which left me scratching my head for a while.

 

The problem is that the SAD backfeeds the solenoid wire as it earths via the starter solenoid, which isn't normally an issue but the relay is much more sensitive and will energise with just a small amount of voltage/current. The SAD is powered from the tachymetric relay, which primes on ignition on, hence triggering the starter and getting you in a loop.

 

You can prove if this is the case by unplugging the SAD and seeing if the starter then works as it should. Be warned though - with the SAD unplugged, it will idle far too high once warmed up!

 

The fix, on mine at least, was to disconnect the starter solenoid wire at the brown multiplug under the dash, and to run a new wire from there to the switching side of the relay, rejoining the original starter solenoid wire (which the SAD connects to in the bowels of the loom) to the solenoid itself. This means that the solenoid gets the full voltage feed from the relay, but the SAD can no longer trigger the relay to make the starter fire when it shouldn't.

 

Since doing that on mine, it's worked perfectly and started on the button ever since

[ablister 31]

I'd take Anthonys advice first before you check what i have said!

[ScoobyJawa 23]

I had this issue which left me scratching my head for a while.

 

The problem is that the SAD backfeeds the solenoid wire as it earths via the starter solenoid, which isn't normally an issue but the relay is much more sensitive and will energise with just a small amount of voltage/current. The SAD is powered from the tachymetric relay, which primes on ignition on, hence triggering the starter and getting you in a loop.

 

You can prove if this is the case by unplugging the SAD and seeing if the starter then works as it should. Be warned though - with the SAD unplugged, it will idle far too high once warmed up!

 

The fix, on mine at least, was to disconnect the starter solenoid wire at the brown multiplug under the dash, and to run a new wire from there to the switching side of the relay, rejoining the original starter solenoid wire (which the SAD connects to in the bowels of the loom) to the solenoid itself. This means that the solenoid gets the full voltage feed from the relay, but the SAD can no longer trigger the relay to make the starter fire when it shouldn't.

 

Since doing that on mine, it's worked perfectly and started on the button ever since

 

Top man - thanks Anthony!! I'll investigate

[ScoobyJawa 23]

Right, nail on head Anthony!

 

With the sad unplugged all works as it should. I'm a little confused about your fix though.

 

So, disconnect solenoid wire from brown multiplug in the dash connect a new cable from there to the relay trigger pin 86.

 

You then say you rejoin the original solenoid wire to the solenoid, but isn't this now disconnected by the new wire? And where does the relay fit in supplying power direct from the battery to the solenoid that way? Where does the disconnected end of the original wire go? To the pin 87?

 

I think I'm just being dumb! But appreciate the help, this solenoid issue been driving me mad for ages lol!!!!

[Anthony 1,003]

It'll make more sense if you think what you're trying to achieve - you need to make it so that the original starter solenoid wire (that feeds the SAD and tachymetric relay) on the engine loom is no longer connected to the trigger (pin 86) on the relay, but so that it does still see 12v on cranking.

 

• Disconnect the original solenoid wire from the brown multiplug under the dash, but leave it connected to the back of the starter solenoid.
  
• Run a new wire from the underdash brown multiplug to the trigger (pin 86) on the relay
  
• Connect the output (pin 87) from the relay to the starter solenoid in addition to the original solenoid wire that's still attached.

 

That way, the only thing that triggers the relay is the ignition barrel, the tachymetric relay still sees 12v on cranking, and the SAD will work as it can earth via the solenoid.

 

Make sense now?

[ScoobyJawa 23]

Ok yeah I think I've got you now, so essentially the multiplug end of the wire stays disconnected and you get 2 wires going to the solenoid - original and relay one with new wire from multiplug to relay

[Anthony 1,003]

That's the one

[ScoobyJawa 23]

Thanks mate you are a star!!!!

 

All done and working, wired up just as above. What a novelty it is to turn the key and it fire/start first time, every time. Well pleased