starter relay..ing ?

[westy64]

Hello,

I have read many threads about the ignition switch protection, considering that it would be interesting to relay the engine starter, by routing the red wire to a relay, etc....

I understand there are pros and cons,

And english is not my mother tongue so there are parts of threads I do not catch.

But

looking at this diagram,



I would have thought that the starter is already relayed.
the red wire acts on the solenoid that closes a power loop which does not pass through the ignition switch, as the starter stud is directly powered by the battery.

Am I wrong ?

Thank you for your inputs.

[focodave]

Westy64,
Yes, the starter is already equipped with a relay.
Most, if not all, automobile engine starter motors are activated by a starter relay because starter motors draw way too much current for any ignition switch to be able to withstand.

[westy64]

Thank you Dave,
So why so many posts about relaying the starter, then ?

[azruss]

several have stated that they use a relay to fire the starter solenoid and improved starting, especially with an old and tired ignition switch. I'm like you as it seems redundant, but you cant argue with results.

[TX82FIAT]

I'm not sure if the posts are talking about a "starter relay" but would put it in the bucket of multiple other relays to take load off of the ignition switch as well as improving voltage delivered to the ignition switch via the starter post. In this case the starter post is a shared point to distruburte power. In the spiders all the lights, wipers, heater fan, and radio run through the single terminal on the ignition. The brown wire fix is about making sure you have a clean/tight connection at the starter and adding a second #10 brown wire from the starter to the additional #30 terminal on the back of the ignition switch. On my car there is a plastic connector between the starter and the ignition that was extremely corroded as well creating voltage drops. Just like water being delivered to a faucet by two pipes increases water flow so will two wires increase voltage to the linked ingnition terminals on the ignition switch.

An example for the multiple other relays would be the headlights. The original factory circuit would only be used to switch the power on to the headlights when a relay is installed. The power from the headlights would come from the alternator and of corse be fused. This would reduce the constant draw across the ignition switch by the headlights.

I'm not sure if I'm being clear with this since I'm not an electrical expert and struggle in this area. Clean grounds all the way around, additional voltage from the stater post to the ignition switch and a relay or two(Example, headlights or Quasi relay for stereo being powered by battery to amp) will greatly improve the function of your components and prolong the life of your system/wires/car.

If I've jumped off on an tangent because I did not understand the starter relay question I humbly apologize and look to be educated. Just don't understand the concept of a relay on the starter. Maybe i would need to be better educated on the function of a "starter" to understand the need for a relay on it. That is why I assume we are not talking about a starter relay. I don't think I get it! Thanks, Ray

[westy64]

Ok my friends,

I was thinking of this kind of threads.
http://www.fiatspider.com/f08/viewtopic ... ay#p100980

You find in the same thread two opposite facts.

So, what is the truth ?
Is there or not huge power going through the ignition switch to power the solenoid ?

tx82fiat,
I am aware of the need to relay the lights, wipers and to free the ignition switch from all these powers.
I will do it, but I just wanted to have my thoughts clear about the starter.

[TX82FIAT]

Westy64, thanks for the additional information. I can see where the starter solenoid would draw some amps at start though the ignition switch. However, I'm still struggling a little with continuous draw of amps by the starter once the car is running. I think that may be your original question and I misunderstood the previous posts. Thanks, Ray

[focodave]

Westy64,
I owe you and everyone else on the forum an apology for misleading information.
I stated that the Spiders had relays for the starter solenoid.
Mine does -- it looks like a P.O. installed it (my car has had several previous owners).
But as I look at the schematics, it appears as though the original circuit(s) did not have a starter relay installed from the factory.
If you want to install a relay in the starter solenoid circuit, it won't hurt anything and it may even reduce the stress on the ignition switch some.
Many other makes of cars I have worked on did, in fact, have a starter relay from the factory -- so it can't be a bad idea.
Dave

[westy64]

Well, after a few hours of websurfing, I think I am closer to the truth.

I think all starters equipped with solenoid are relayed by.... the solenoid.
The starter consumes around 300A (depends on the engine, etc...) in a power loop switched by the solenoid (as a relay).
But the solenoid also need some power to act, and this would be around 30 amps, passing through the ignition switch.
So yes it is also worth relaying the solenoid, and I will do it soon.

I should have an ampmeter somewhere in a box from a previous project and I will use it to measure the power used by the solenoid (red wire).
this will give us some data (at least about the starter which is in my car).

to be followed.

jean

[azruss]

jean,
the starter solenoid has to do more than just make the physical connection in the high amp circuit, it must also engage the bendix drive.

[westy64]

Azruss,

I agree. Just did not mention it as this (in my mind) was not greedy in power.
But you're right, that's the main mechanical function of the solenoid.