Technical Losing ignition

[Tiller]

I experience loss of ignition with my 1970 Fiat 850.

It happens when i lett go of the accelerator pedal for braking or to change gear.
I have to try starting again a few times before i get the ignition back again.

Seems to happen more ofte when engine is cold, but also happens when warm.

Never happens while driving.

Where to search for faults? And what could it be?

 

[Gary50]

Hi
Check the earth strap from the engine (usually near gearbox) to body. If this is frayed or rusty connection it could be the source of many woes.
Cheap to fix but often the last thing to look at... usually after you have spent loads of money and hours working through the ignition system.

With old vehicles it never hurts to add an extra earth strap in a different location - just make sure it won't foul on moving parts.

 

[FR85]

I think this is a slight breakdown in communication, when you say you lose ignition, you mean the engine cuts?

Which carb have you?
Check the idle jet, make sure its clean and not clogged, check any filters you may have inline and indeed the one in the carb and also maybe leave the choke on until she warms up a bit.

 

[Tiller]

I think this is a slight breakdown in communication, when you say you lose ignition, you mean the engine cuts?

Which carb have you?
Check the idle jet, make sure its clean and not clogged, check any filters you may have inline and indeed the one in the carb and also maybe leave the choke on until she warms up a bit.

Engine and loss of electricity.

I have to turn the ignition on/off a few times to start it.
If the cat rolles i can manage to roll-start it.
Dont know if that is the correct english term

 

[FR85]

Engine and loss of electricity.

I have to turn the ignition on/off a few times to start it.
If the cat rolles i can manage to roll-start it.
Dont know if that is the correct english term

You are definitely losing spark?
12v to the coil is gone?

Cap, points, condenser, coil and leads are all in good condition?

Timing has been set?

Sorry, Gary50 could be spot on on the earth strap theory, I fitted a second one going from the engine under tray bolts to the water pump at the shroud mount.

 

[Tiller]

You are definitely losing spark?
12v to the coil is gone?

Cap, points, condenser, coil and leads are all in good condition?

Timing has been set?

Sorry, Gary50 could be spot on on the earth strap theory, I fitted a second one going from the engine under tray bolts to the water pump at the shroud mount.

Yes i am losing spark and all electrics shut down.
Cap, points, condenser and coil are reletively new and timing has been set.

I have fitted an extra earth strap to the battery and engine + replaced the original earth to a new and sanded the connecting points.

Its very intermittent. Some days all is good, and some days it can happen randomly and often.
What i just noticed is that when the car is in a "bad mood" ant the fault seems to happen more often, i loose my dipped beam on the left side.
Very strange. And on good days when the fault does not appear the dipped beam works.
Thought it was a bad bulb, but it happens regardless of new/old bulb.
Have just tried to freshen up the earth for this head light to see.

 

[Tiller]

In addition: When the car is in a "bad mood" and the fault appears more often, the engine and electrics cut when i try to use the turn signals and fires right up again when i turn the turn signals off

 

[Tiller]

To sum it all up:
Intermittent fault
Good and bad days. Some days everything works without problems and some days the car seems to have a bad mood and the fault appears more frequently.
The car lose ignition and all electrics when doing the following:
-Let go of the accelerator to change gears or brake. (Can compensate by keeping high revs while changing gears and braking)
-Using the turn signals

When the car is in a bad mood i have noticed that i lose the left dipped beam. So that is a sign that she is going to misbehave.
On good days when the fault does not appear the dipped beam works.
Thought it was a bad bulb, but it happens regardless of new/old bulb.
Have just tried to freshen up the earth for this head light to see.

What i have done:
The cap, points, condenser and coil are reletively new and timing has been set.
New spark plugs

I have fitted an extra earth strap to the battery and engine + replaced the original earth under the car (gearbox) to a new and sanded the connecting points.

 

[Gary50]

In addition: When the car is in a "bad mood" and the fault appears more often, the engine and electrics cut when i try to use the turn signals and fires right up again when i turn the turn signals off

This is suggesting a short in the wiring loom.
Check where your loom goes through the bulkheads and for damaged insulation.
Start from your left dipped beam and work your way back following the loom.
With the engine off, turn your dipped beam on and then flex the loom as you go along to see if the beam goes off, the break maybe inside the insulation so may not be immediately obvious.

Hope this helps.

 

[FR85]

You have a short some where which could be bump in the road/vibration induced. My 500 used to die when I turned on the lights at the main switch, two wires had eaten into one another behind the ignitin barrel and shorted.