Ignition Switch problem?

[Justice777]

So I' off on my maiden voyage in my '78 124 spider, stop and get gas. Car won't start, cranks over fine, elect fuel pump on. I get out, open hood, check choke (open), get in and try to start again. Turning over fine, then fires up at same instant as I let go of key. Get out and close hood, get back in and it dies just like someone threw a switch. Had some high schoolers push me across parking lot, fuel pump on, key in "on" position, 2nd gear, pop clutch and it fires right up. Drive home, back in to garage, shut off. Try to start and same thing - turns over but doesn't start.

I have to head off to work but wanted to pose the problem to you all. Seems a bad ign. sw?

[RRoller123]

That would be a likely suspect! This is pretty common, unfortunately.

[Justice777]

Thanks. I went ahead and ordered one. I believe it has been replaced once, then headlight relay conversion. Hoping they can overnight it as the weather here right now is too nice to miss out on.

How long do these typically last?

[spider2081]

Does the front of the ignition switch have roman numerals on it or does it say Sepia on it. The original switch would have Sipea stamped in the shinny face.

[Justice777]

Roman numerals.

[RRoller123]

Spider2081: Do the roman numerals make it a Lada?

[spider2081]

Spider2081: Do the roman numerals make it a Lada?

From what I have seen yes. There are some very early Sepia ignition switches used in the Spiders and I believe Fiat Dino's that use the same pin configuration as the Lada switches. All the Sepia switches I have seen have Sepia stamped into the front shinny dress piece.

The quality of the electrical switch assembly part of the Lada switches is made cheaper than the original design. They are designed to be used to control relays and Fiat Spiders did not originally come with relay controlled circuits. I believe the Lada's did use relay controlled circuits by design. The Pininfarina 1983-85 Spiders came from the factory with headlight relays. Fiat Spiders only had a "start" relay on the automatic transmission cars and I think with the seat belt interlock circuit for a year or 2.

[Justice777]

While new ign. sw. is in transit I decided to pull existing one, thinking since it's 80'F outside maybe I could simply hotwire the car and go for a spin (recall I just got this and summer is ending soon). Here is a picture of pigtail that was connected to back of switch:
https://i.imgur.com/htzmBOa.jpg
...so yea, it obviously had resistance at connectors and got pretty hot.
Looking at diagram,:
https://i.imgur.com/9LrRmKV.jpg
and my previously modified pigtail, it seemed if I made 2 jumpers:
One to connect pink to blue and to black - this made dash light up and provided 11.2v to one side of coil (was expecting to see 12.2v as is across battery).
One to briefly jump starter - brown to red - this energized starter.
With fuel pump turned on, pink+blue and black jumpered, energized starter - engine turns over but wouldn't fire.

Am I missing something? I've been searching here and on mirafiori... So frustrating. My existing ign. sw. had 5 wires going to it as seen on the pigtail image above. Pink and Blue jumpered to Black, then touch Brown to Red to turn starter.
Any help is appreciated.

Edit: Existing connections to sw. were: Pink and Blue = 15, Black = 30/1, Red = 50, Brown = 30.

[spider2081]

The original Sipea ignition switch had 3 sets of contacts inside the switch. The brown wire fed momentary power to the red wire for starter solenoid and "run" power to the blue wire. The other set of contacts is powered by the black wire and when the ignition switch is in the "run" position powers the pink wire that primarily powers the ignition system of the car. The Lada switch has 2 sets of contacts. One for the start position and one for the run position. That is why in your photo the blue and pink are connected together. It could also be why the black wire in your photo shows signs of over heating.

I would connect the brown,black,pink and blue together to simulate the run position of the ignition switch. That way both wires that originally brought power to the original ignition switch are being used. Then momentarily touch the red wire to the others for the starter to be engaged. Your car has a carburetor so it will crank a bit before fuel gets to the carburetor.

[Justice777]

OK, will try. Thank you. I was not aware Brown was tied to "Run" circuit and I just used it to touch to Red to engage starter.
I'll give it a shot in the morning while waiting for new switch (off to my evening job right now) .
I am considering testing new switch and if all goes well then soldering instead of using connectors.

[baltobernie]

They are designed to be used to control relays and Fiat Spiders did not originally come with relay controlled circuits. I believe the Lada's did use relay controlled circuits by design.

The Lada harness I have does not connect to any relays in the starting or running circuit. You can see a schematic in this posting: http://www.fiatspider.com/f15/viewtopic ... 19&t=33918

If you bought your replacement switch from one of the reputable vendors you see mentioned on this forum, they will enclose a "cheat sheet" explaining how to wire the Lada switch in your model-year Spider.

ps: Wife & I had a great time in Ogunquit and vicinity a few weeks ago. Lovely area, but after you get your Spider up and running, install a great big honking alternator and some of these:



Seriously, you folks ever heard of roadway paint?

[spider2081]

One needs to have pretty good soldering skills to solder the #10 Brown and the other #12 wires onto the Lada ignition switch. The heat required for a good solder connection easily melts the nylon the contacts are set in. I would not be surprised if the switch that failed in your car actually melted internally.
Have you taken the electrical portion out of the metal housing and inspected it's contacts?? To disassemble the switch I like to put the assembly in the "off" position and then remove the key. Then remove the spring clip in the back and remove the electrical portion from the metal housing.

[RRoller123]

+1 on not soldering the contacts at the ignition. A small torch might do it, but the likelihood is that the switch internals will be damaged. Good, new, tightened FastOns, with clean (new) switch terminals, will do the trick.

[Justice777]

Message received on not soldering. Thanks. I have not pulled old sw. apart yet.
Sw. I am replacing is a Lada (Roman Numerals on face) so wiring cheat already done.
Lol... We DO stripe our roads but take a while getting around to it after new paving, which is MUCH darker than old asphalt.

Seeing this:
http://got.net/~danj/fiat/ign_switch.jpg
referring to spider2018 comment and see what you're saying. I'll give it a shot in the morning.

[spider2081]

http://got.net/~danj/fiat/ign_switch.jpg

The schematics for the "Lada" are what I seem to remember except with the key in the "off" position even removed from the switch the brown wire brings battery power to the switch on terminal 30. Terminal 30 makes contact with the "int" terminal. That leads me to believe the "Int" connections can not be used with the Lada switch. Maybe there is more than one style Lada switch being sold or the one I had was defective.

In the "run" Schematic diagram as I see it Terminal 30 and "Int" make connection as well as terminals 30/1 and 15/54 make connect. This is how the switch I checked operated.

In the "start" Schematic diagram as I see it terminal 30 connects to "Int" and 50 terminals also terminals 30/1 and 15/54 make contact. Again this is how the switch I checked operated.