Ignition Switch and System.

[Sydmn]

I was backing my 1981 Spider 2000 out of the garage when the engine stopped. The engine cranked OK but wouldn't fire. All fuses were OK. Fuel pump ran with external power applied, so was not getting a signal from the ignition switch. I checked the 2.5 pink wire between the ignition switch and fuse A for continuity and the smaller 1.5 pink wire between the switch and the positive connection on the coil.
The two pink wires are joined together just before they are connected to the ignition switch.This spade connector was badly burned as was the plastic sheath of the smaller wire to the coil. Can any one tell me why the joint, which had been OK for years would suddenly get so hot? I can run a replacement wire but I have to know how or why this happened before I make that connection to the Ign. switch.
Any help from you experts would be greatly appreciated.

[aj81spider]

There are only two reasons why a wire would melt and char like that - you are drawing a little bit too much current for a long time or you are drawing a lot too much current for a short time. Either way you have a short or a defective component down stream from the burn.

Do you know for sure that that connection was OK or is it possible it was decaying for a long time before it finally broke?

From your description it sounds like the smaller wire to the coil is melted and the other one is OK. If that's the case I would look at the things down stream from that wire (including the wire itself, which may have chafed against something and shorted to the chassis). If it's less certain that the problem is there you need to look down stream from both wires. I'd start by connecting one and then the other and measuring the current.

These types of problems are generally simple causes that can be quite difficult to track down.

[spider2081]

I don"t think a 1981 Spider would have spade connectors at the ignition switch unless it is an aftermarket ignition switch, possibly a Lada switch. The original Sipea ignition switch had the wires soldered to the terminals on the ignition switch. about 8 inches behind the ignition switch there was a 6 cavity whitish nylon connector with 5 cavities used. Does your ignition switch have Sipea stamped into the shiny face of the switch? If it has symbols similar to roman numerals its more likely a Lada after market switch. It is not uncommon for the Lada switch contacts to overheat and melt the wires connected to them.

[dinghyguy]

If you have a sipea swith it can be rebuilt. There is an article in Mira about it which i used as the basis for my own document (not yet published but avail). In the course of doing the work on both my spiders the which connector mentioned in the post above was brown on one and toasted on another such that the PO had jumpered it and part of the ingnition switch.
The recommended fixes are:

• Clean all the contacts in the white connector and make sure they have a bit of conductive grease. This required Disassembly of the spades out of the plastic bits to do it right.
  Disassemble and clean repair the ignition switch contacts (or replace the ignition switch)
  Install relays to take the load off the switch particularly when starting.
  Install relays to handle the headlight loads.

Then all our problems will go away until you find the next electrical issue the PO left you.....

cheers
dinghyguy

[Sydmn]

Thanks for your reply's.
My car has the SIPCA switch. The short wires are initially soldered to the switch and most use push type connectors to attach the longer wire runs, except the pink wires. As shown on the Fiat Wiring Diagram they were combined in the female half of a spade connector. I replaced the thinner (1.5) pink wire which went to the coil with a slightly larger dia blue wire with a spade connector on it. I had to extend the larger (2.5) pink fuse wire using a inline connector to a 2mm dia x 4"copper house wire which had the female half of the spade connector attached.
I connected every thing as best I could and turned the ignition to it's first position, while watching the new blue wire very closely. The first success was the fuel pump ran but I could feel the new blue wire getting warmer, this after onlya few minutes, so I shut it down. It looks like the general opinion is that I should open up the switch and clean it or possibly replace it. To that end could dinghyguy possibly send me a copy of his service document if we can make the arrangements.
I still don't under stand why that wire gets hot so fast May be I should solder all the joints?

[spider2081]

The Sipea Ignition switch is the stock (original type) installed at the factory. There are more than one versions of the switch and the Mirafiori repair instructions address only one type but could be helpful with the other types.
Your wires are soldered to the terminals of the ignition switch. in order to remove the contacts from the plastic (micarta) housing for cleaning 100% of the solder needs to be removed from the contacts. Then on reassembly the wires have to be re-soldered to the terminals. This requires above average solder skills.
I believe the blue wire from the ignition switch powers the headlight switch. The current for almost all the light circuits passes through the blue wire when the ignition switch is in the on position. That would include the headlights, parking lights, dash lights. side lights, Does the blue wire get warm if the headlight dash switch is in the off position??

Also where are u located?

[Sydmn]

Yes, the blue wire from the ignition switch goes to the headlight switch. I can't check it for temp. at the moment as I have got several ground connections free while I clean them up. Half an hour ago I tried to run the engine and a black ground wire from the positive coil connection (U) to a Fiat ground connection point on the upper right fender just below the rain gutter, fried it's self. The whole length of a roughly 12/14" length of wire. I don't know if that wire was supposed to be there but it has been there for a longgggggg time. Do you have such a ground? I'll try and check the blue wire temp. later on to-day.

[Sydmn]

I'm sorry I forgot to add my location which is Tacoma Washington

[spider2081]

well you are pretty far from me I'm in Wallingford, ct

The original coil would have a B+ terminal and a D terminal. The B+ terminal would have a blue/black wire comiing from the ignition switch the D terminal would have a brown wire for the tachometer and a brown or brown/white wire that goes to the distributor pick up. neither coil post should be hard wired to ground.

The way a coil works is power is applied to one side of the coil the other side of the coil connects to the ignition points. When the points are closed (which is most of the time) current flows through the coils windings and builds up a magnetic field. When the points open the magnetic field instantly collapses producing the high voltage for the spark plug. If you have an electronic ignition the electronics mimic a set of points. some coils require a ballast resistor to operate properly. Fiat installed the resistor between the coils D terminal and t he ignition points. Most electronic ignition systems eliminate the ballast resistor.

[Sydmn]

I have tried to start the car but I need a new distributer pick up, one of the little wires is broken. The good news is nothing else got hot. I checked the wire to the coil which I added to replace the burnt pink wire, the blue wire to the light switch and many other's. I couldn't find any that were warm. I didn't replace the black wire that ran from the positive coil terminal to ground and got burn't up. I'll order a new pick up to day.

[spider2081]

I didn't replace the black wire that ran from the positive coil terminal to ground and got burn't up.

The B+ terminal of the coil should have the pink wire with push on spade terminal, A short black wire to the radio filter capacitor and a short red wire to the ignition control module mounted under the coil in the heat sink. The coils other terminal should have a brown wire for the tachometer, a black wire to the ignition control module and a brown/white wire for the fuel injection computer.

There is a ground wire that has a ring terminal attached to it. it goes under the aft bolt that holds the heat sink bracket to the fender well. The other end of that wire also has a ring terminal and goes on one of the 3 studs holding the rear cover for the cam on the cam box.

[Sydmn]

I want to make sure that I have the correct coil on my car. It is a Magneti/marelli BAE207A and the posts are exactly the same size and mounted on the top flange. One of the posts is marked +B so I have taken the other to be -ve. The resistance between the posts is o.7 ohms and between a post and the center 10.54K ohms.
On the +B post I have : Pink wire from Ignition switch.
Red from the control module
Black from the Radio noise capacitor.
On the other -ve post I have: Black from the control module.
Brown/White to the Tach and control unit.
Yellow in black sheath to #1 in the control unit.
Would some one look this over and tell me if I Have it correct?

[Sydmn]

The car is runnig fine. I am working on replacing some of the lines that got damaged and improving some of the connections. Many thanks for your help.