Electrical Glitch

[steve lapp]

Hi folks:

Engine dies suddenly! Ok, here are the symptoms and what I have looked at. The car electrical systen is original, no weird sphagetti of extra wires.
- all electrics except interior lights die while car is running, it has only happened at low speed while slowing down (with or without brakes applied). All gauges dead, no starter, no starter solenoid, no fuel pump, no lights. Happens when cold or hot, dry weather.
- car startes after 5 to 10 minutes with no problem

While car is running but slow or stationary I have:
- pressed brake to no electrical effect
- jiggled battery and battery wiring to no effect
- jiggled fuses to no effect
- jiggled wires behind ignition key, behind fuse board and behind dash to no effect
- the battery cranks storngly once the gremlin decides to go play somewhere else.

Thoughts welcome.

And diverting slightly to the thread about what "time" period to restore your car to. I have decided that mine has already been restored to a future time period. It even has the rust, dents and blue smoke to show 40 years of hard use in between now and that future time period.

Cheers
steve

[250GT]

Hi folks:

Engine dies suddenly! Ok, here are the symptoms and what I have looked at. The car electrical systen is original, no weird sphagetti of extra wires.
- all electrics except interior lights die while car is running, it has only happened at low speed while slowing down (with or without brakes applied). All gauges dead, no starter, no starter solenoid, no fuel pump, no lights. Happens when cold or hot, dry weather.
- car startes after 5 to 10 minutes with no problem

While car is running but slow or stationary I have:
- pressed brake to no electrical effect
- jiggled battery and battery wiring to no effect
- jiggled fuses to no effect
- jiggled wires behind ignition key, behind fuse board and behind dash to no effect
- the battery cranks storngly once the gremlin decides to go play somewhere else.

Thoughts welcome.

And diverting slightly to the thread about what "time" period to restore your car to. I have decided that mine has already been restored to a future time period. It even has the rust, dents and blue smoke to show 40 years of hard use in between now and that future time period.

Cheers
steve

Hi Steve,
to let the "time"speaks is the right way.
to find oud electric problem can be difficult from here.
I had this on a Maserati with I change to "modern" elextronic ignition.
Which was a mistake !
I could find out by cooling down the electr. blocks with ice spray(cold air) .
suddenly every thing works again.
But if this helps is the question in your case.
ice spray is a option to test out coils and other electric components .
Stationair idle let the temp go high in the motorbay no cooling down from driving.
This could be an explanation for " sudden death"

Best
C.

[tyang]

Hi Steve,

I don't know if I have an answer because of the clue that the interior lights remain on when everything else goes off. At first I suspected the wiring connections to through the ammeter gauge, but why would the interior lights still work? I was also going to suggest checking the grounds, but again, why would the interior lights still work?

Tom

[330GT]

The interior lights, horn and exterior lighting are all independent of the ignition switch. All other electrics depend on power from the ignition switch, either in the accessory or run position.

If the horn and headlights also work, then I think you have a problem with the wiring to the ignition switch or the switch itself.

Picture1.jpg (85.72 KiB) Viewed 9133 times

If you look at the wiring diagram, fuses C1 and C4 are fed by the RUN position. C5 and C6 are from the Accessory position. Block D1/D2 are fed from the ammeter (black wire) and alternator (green wire). All lighting comes off fuse B6, down to block G2 for distribution. The horn relay (#8) if fed from G3/4 which is fed from fuse C3.

So you need a voltmeter with you the next time it dies and start checking some voltages. If lighting works then you have to have power to D1/2 and G2. You need to check the RH sides of C1,C2, C5 and C6. If no power there, check the incoming wire to the ignition switch (large red wire fed from D1/D2), the accessory feed (large black feeding fuses C5 and C6) and the run feed (large blue feeding fuse C4) along with the blue jumper to C1. Somewhere during this, you will narrow down your failure point. Here's a picture of a fuse panel for orientation.

MVC-451X.jpg (98.66 KiB) Viewed 9134 times

[8339]

Steve

I'm assuming by the VIN this is a series one or very early series two car. If it's a series one car, the ignition, and keyed circuits run through the ignition switch. As these switches get old the resistance gets high enough to heat up and kill the operating circuits, the interior lights work off a separate circuit. The series two cars have an ignition relay operating from the ignition switch which reduces the current at the switch by large amount. Ammeters are also suspect, however the ones I've seen fail just go away and don't come back, however it's worth looking at. I would first look at the ignition switch, if it's a series one car with the key push feature of the starter circuit, it's possible to pull the switch apart clean and put it back together again. You'll probably find all kinds of old grease, dirt etc, just the stuff to heat up while your driving. If it's a series two car look at the ignition switch as well but also find the igntion switch relay, it should be on the fuse panel. One other thing, these old fuse panels will build up a lot of resistance due to dirty fuse terminals, clean every one and put new fuses in. Be careful of the brand of fuses, I have used cheaper Chinese fuses and have had them blow very easily. Go to a real auto parts store like NAPA and ask for Buss brand GBC style fuses. Hope this helps.

Richard Garre
Radcliffe Motorcar Company

[250GT]

Steve,
you was writing "it has only happened at low speed while slowing down.
this must be the clue for you're problem.
I hardly can substute something new with so much right knowhow in the back from Richard and Kerry.
it must have a connectiuon with RPM.
The switch dont get extra hot at idle.
I would set up the carbs at 1200 rpm and look whats happening..... simple.
If you have upgraded an newer alternator this could be an item too
the newer once need a so called " exciting current" and dont supply electricity in that moment.
the resistance in the whole circuit is higher and let die the engine.
only a thought.
So cleaning everything- see above- is absolut necesarry.

C.

[steve lapp]

Hi experts:

Busy at work so have not been able to sort car. I like the idea of the igniton switch heating up (it is a non original replacement with no push feature). I have the original too, so maybe time to rebuild it! I also had not worked up to jiggling the wire on the ammeter, and that is a good idea too. Hopefully some warm weather this weekend will allow a few more rides and a chance to check it out.

As always, Thanks

steve

[Jimmyr]

One area that I have written about several times in the FCA tech site is the jumper block on the fuse panel. This is the square block with the heavy wires attached. The wires are held in place by 4 set screws. The copper wire ends are solder coated, the wire housing is steel, the screws are brass, etc. With all of these different metals corrosion is very likely. Remove each wire and clean it well, the same for the heavy copper jumpers. These are a common trouble spots on most all Ferraris of the era, and are usually never inspected. Jim

[steve lapp]

Took a while to get back to the car and this problem. My son and I went for one last drive before putting the car away and sure enough, it dies. But the usual ten minute wait for things to recover turned into 20 then 25. Eventually with my son turning the key and me at the fuse panel, I wiggled each wire until I found the culprit, yes indeed it was the lower left wire on the lower right terminal block (# 16 in Kerry's above diagram) where wiggling allowed the car to start. Now back in the garage for the winter I can properly clean up all those wires. My son and I did a video in the car on a very nice twisty road and I will see if I can get that posted before next spring, he became car sick from the fun ride - so you see a small blond head with hands over his face in the passenger seat. I hope he remembers helping me fix the problem more than his motion sickness.

Thanks to all the contributors - many minds make light work.

Cheers

[steve lapp]

For all those who helped with the electrical glitch. The last of the fall fun, to be played on those cold rainy winter days.

http://www.youtube.com/watch?v=Pos1V5DuQs0

cheers
steve

[T308]

Nice, can you boy see over the dash?