GT4 Electrical Problem Could Use Some Expert Help!

are you sure its not a worn out ignition switch? very strange, and it seems to depend on how many times its been started.

 

I second 2NA. Regardless of thier appearance, I would check the battery terminals by physically removing them and cleaning the terminals. You said you have a battery disconnect, I would inspect it thoroughly. While your in there, I would have the battery load tested. If there is no problem, check your starter terminal leads and engine to chassis grounds, as well as the main power lead at the fuse panel.

 

Bob. You have the electrical function drawings. Print the 'Power Distribution' circuit page and a using a voltmeter and your logic, determine where you have voltage and where you don't.

The circumstance of a short causing the problem is a non-issue as is the starter solenoid. You have an open somewhere between the battery and the components in question.

Orderly rule out the battery ground, then procede with the + from battery to the 4-way block (noting the starter is between them) then the ignition switch.

 

Dont remove the lock assembly. If your thinking its the switch, its screwed to the lock assembly from behind. disconnect battery, remove two screws and remove just the switch (the part the wires attach to). I dont know the part number but the switch is from an old BMW 2002 IIRC. About $65 last I heard?

 

Rob,
If you do find that it's the ignition switch, read John Corbani's Dino Saga 050911. He presents an interesting approach to repairing and 'preserving' the switch.

http://ferrarichat.com/forum/showthread.php?t=74532&highlight=050911

Even if you determine your ignition switch is OK, you might want to adopt his flyback diode concept.

Also, read & see more here (incl pics & part no)

http://ferrarichat.com/forum/showthread.php?t=148452&highlight=050911

Corbani's Dino Sagas pertain to his '72 246 type E, but are often adaptable to 308s. If you haven't already done so, check 'em out; use the index for reference

http://ferrarichat.com/forum/showthread.php?t=204474&highlight=050911

Also, have you seen these 308 wiring diagrams? 'might come in handy!

http://www.ferrari308gtbi.com/

Cheers,
Coop

 

I sent this email to Rob last night, then realized it might be helpful to other folks.

I spent some time looking at the schematics and the shop manual. Now. bear mind you are dealing with a 30+ year old electrical system. Insulation gets brittle and cracks, contacts get minute fretting corrosion, and problems are likely to be intermittent. I know you keep your car in tip-top shape, but you can't check every wire and connection.

Let's start with the way it is supposed to behave. If you look on page 14 of Section I in the shop manual it tells you what the four positions of the ignition switch are supposed to do, Compare them to the symptoms you are seeing and note the deviations.

You had some questions about the seatbelt buzzer. There is a part (0201536), #21 on Tavola 121 called "Cicalina." In my Italian English Dictionary a "cicala" is a "chatterbox," so I think its safe to assume a cicalina is a "little chatterbox," better known as a buzzer, specifically the seatbelt buzzer on US spec cars.."Centalina" #22 means "telephone exchange," so I'm going to guess this means some kind of timer switch, like a dial tone or a busy signal. I think that's supposed to ring the buzzer and illuminate the "seatbelt" light for a period of time, say 20 seconds, then shut it off. These kind of old timers don't age well, so I'm going to ignore your issues with the seatbelt light/timer.They shouldn't affect starting the car.

You should be able to check your ignition switch with a VOM. or trouble light. Connect the hot lead (#30) to 12 volts, then check the other contacts, #75, #15, and #50 at the different switch positions, jiggling the key to see if they are intermittent.

One thing I did notice is that the hot wire (+) from the battery goes to only one place - the starter. There are three wires on that lug on the starter - one from the battery, one to the alternator and the third goes back up the central tunnel thru the four-way connector and to the relay box and the fuse block, where it gets distributed to the rest of the car. These wires are hot (unswitched) all the time.

You said that when the problem happens everything goes dead in the car. That means the problem has to be someplace in the electrical system common to all the systems. That basically narrows it down to the wire from the battery to the starter motor, then the wire from the starter motor to the 4-way junction in the fusebox.

I would start at the starter motor and inspect those connections. Then inspect the wire to the Alternator and the wires themselves, looking for any frayed or cracked insulation, especially where the wire bundle goes through the firewall. Because this spot is hot all the time you could hook up a temporary trouble light here and pull it up through the engine compartment where you can see it. While it is on that means that the circuit from the battery to the starter is OK. Wiggle the wires I mentioned and if the trouble light blinks or goes out you either have a short or an open wire near where you are wiggling.

Then I would look under the center console, especially around the parking brake and under the window switches, looking for frayed or cracked insulation.. Wiggle these wires again watching the trouble light.

You can do the same thing at the 4-way junction in the fuse box. Hook up a light to the junction and wiggle the wire.

You sad you were messing around with the window switches on the center console. check those wires - is it possible you got one or more plugged into the wrong lugs?

Be patient and don't get discouraged. electrical troubleshooting is no fun, but it is logical And remember, We are Men. We have tools, We can fix anything.

Good luck and let me know how it turns out. I'll be leaving for Denver on Tuesday, but will check my email.

Mike