Starter relay

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thecarnut
Posts: 7
Joined: 07 Oct 2015, 22:57

Starter relay

Unread post by thecarnut »

The starter relay on my 62 Flaminia GT will not engage the solenoid. The solenoid and starter work fine when I apply power directly to the solenoid. What is strange is that the Bosch relay will click if the solenoid is disconnected but will not when connected. This relay has a large capacitor attached to it. It would be of great help if someone could explain how this relay is supposed to work and what function this capacitor plays. Enclosed is a photo of the relay.

[attachment=0]Flaminia starter relay.jpg[/attachment]
Attachments
Flaminia starter relay.jpg
Pierre VALLADE
Posts: 247
Joined: 01 Oct 2009, 14:49
Location: Calvados/ Normandie / France

Re: Starter relay

Unread post by Pierre VALLADE »

Hello,

Sorry for my very poor English, but if it helps.

The capacitor is used as a system to prevent the action of the starter if the engine is already running.
When the engine is running, the capacitor is charged by the dynamo, the voltage across the capacitor prevents the starter relay from being activated.
When the motor is stopped, the capacitor discharges (in seconds or fractions of seconds), so the relay can be operated again.

Warning: I once had a relay wire that was disconnected, this prevented the relay from working and therefore the starter from turning. I don't remember which wire and the car is far from me at the moment. May be later but I don't know when.

Best regards.

Pierre VALLADE
thecarnut
Posts: 7
Joined: 07 Oct 2015, 22:57

Re: Starter relay

Unread post by thecarnut »

Thank you Pierre, this is VERY useful and your English is perfect. I do not need this relay to protect me from starting the engine while it is already running. I will take the relay apart and see if there is an easy way to bypass this extra protection.

Ivan
thecarnut
Posts: 7
Joined: 07 Oct 2015, 22:57

Re: Starter relay

Unread post by thecarnut »

Problem solved.

I thought the big Bosch relay and capacitor were a starter relay but thanks to Pierre's explanation I now know that it is only a "safety device". None of my other vintage cars has anything that prevents me from engaging the starter while the engine is running yet this has never been an issue. So the easy solution was to run a wire from the ignition switch directly to the solenoid and thus bypassing the Bosch cut off relay. Car starts reliably and there is no danger of this contraption failing in the middle of a road trip.

Ivan
Pierre VALLADE
Posts: 247
Joined: 01 Oct 2009, 14:49
Location: Calvados/ Normandie / France

Re: Starter relay

Unread post by Pierre VALLADE »

My two cents and just my opinion.

I agree about the fact that good drivers and owners never try to start the engine if it is still running.
But the problem may be elsewere
Using the ignition switch in order to have current at the solenoid may not be a good solution, even if it works ... for a small time.

The amperage (required by the solenoid) in the ignition swith is probably very high for the contacts and these may deteriorate over time. I still suggest using a standard relay. So the ignition switch will be protected.
It is quite difficult (and expensive : there is one used for sale at 270 € ) to find an ignition switch while a standard relay can be easily found.

Pierre
thecarnut
Posts: 7
Joined: 07 Oct 2015, 22:57

Re: Starter relay

Unread post by thecarnut »

I agree that adding a relay would minimize the load on the (expensive) ignition switch. The contacts of the Lancia ignition switch look much heavier duty than the ignition contacts used by Maserati on their cars and those cars did not have a starter relay. Still, I like your suggestion as it is very easy to add and hide behind the dash.
Ivan
Pierre VALLADE
Posts: 247
Joined: 01 Oct 2009, 14:49
Location: Calvados/ Normandie / France

Re: Starter relay

Unread post by Pierre VALLADE »

In addition to my last message. Sorry for my poor English, I'm not good enough for automotive language. Thanks for the "Google translation".

The starter solenoid behaves like an electrical coil. Therefore, on breaking the electric circuit, an arc occurs which will damage the contacts.
A modern relay is welcome and easier and cheaper than the ignition switch.
I think there are all the necessary wires near the current relay (the one on your photo) in the engine bonnet. If I remember well, there is a thread coming from or going to ...
A) the ignition switch,
B) another from the fuse box (fuse number 12 according to the wiring diagram),
C) another from the dynamo charge regulator,
D) one that goes to the starter solenoid,
E) the connection to the chassis (-12 volts) is ensured by fixing the relay.
The one (C) coming from the dynamo regulator is the one used for the engine running detection system.
Notice that, wire C also goes to the red dynamo charging incident detection light.
By using wires A,B,D,E there is a way to connect the new relay next to the old one in the engine bonnet. Let the C go to the red light.

But, the best should be to find why the current relay in not working correcty. The new relay may be a temporary solution in order to be able use the car. I bought my Flaminia 27 years ago, and the starter system is still working fine.

Best regards,

Pierre
thecarnut
Posts: 7
Joined: 07 Oct 2015, 22:57

Re: Starter relay

Unread post by thecarnut »

Thank you Pierre for the additional explanation. For now I have mounted a relay next to the ignition switch. All the amperage required to engage the solenoid is now going through that relay and not the ignition switch. No wires were cut and the original Bosch relay is in its place and connected. This can all be reversed at a future date.

Ivan
Wheelwonk
Posts: 2
Joined: 13 Sep 2022, 18:46

Re: Starter relay

Unread post by Wheelwonk »

Hi,
I too have been having issues with my starter relay. I have owned my car for over forty years and yes it worked great but now it is old and cranky like it's owner.
I have taken the starter out and checked it, put on a new solenoid, taken the relay apart and cleaned the contacts, cleaned and remade the battery connectors, bought a new battery, ran a wire direct from the battery to the solenoid via a switch under the dash, etc. Stilllll when the car is hot/warm it won't pass enough power to get the solenoid to engage. Cold it will start right up . If you park it long enough to cool it will start, but if it is warm or just turned off and you try to restart it will click the solenoid but not make it engage and turn over the starter. I checked the capacitor on the Bosch relay and it seems to be working, showing continuity and battery voltage when the car is running, is that correct. Is it a capacitor or a condenser ?
Very frustrating , any help would be most appreciated.
FL30
Posts: 258
Joined: 30 Sep 2009, 19:17

Re: Starter relay

Unread post by FL30 »

Sounds that you have worked all possible issues upstream of the starter (figuratively speaking; at the plus end of the battery). Next thing to check is downstream the starter/solenoid. If the electrical supply goes down with rising temperatures, you may have a contact resistance somewhere. If it is not upstream it must be downstream.

Make sure that the ground cable from battery minus to chassis is first class and has clean contact surfaces. Then ensure the same from chassis to engine. After sixty years the ground strap and/or its contact surfaces may be bad.
Hubert
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