Technical Wire Issue

[John Nolan]

Good evening! I was letting my ‘72 500 warm up this morning but all the sudden stopped after a normal idle. I tried to start it again but no luck. The engine was turning but no spark from the sounds of it.
Upon inspecting the engine bay I found this wire that I cannot determine the correct destination for (picture attached). Any suggestions would be greatly appreciated!

 

[bugsymike]

Good evening! I was letting my ‘72 500 warm up this morning but all the sudden stopped after a normal idle. I tried to start it again but no luck. The engine was turning but no spark from the sounds of it.
Upon inspecting the engine bay I found this wire that I cannot determine the correct destination for (picture attached). Any suggestions would be greatly appreciated!

Looking at the way it is routed , it doesn't look factory wire, so may be unrelated. I can't quite see in the photo but where the other wires go behind a metal clip on body are those wires OK.
However I don't think any of those are related to your starting issue.
It should be eay to see if no spark by pulling the lead from one spark plug, put an old spark plug in it and rest agaist metal of engine whilst some one cranks the engine to see if HT spark.
Although if it was me I would use my multimeter to see if voltage at ignition coil.

 

[fiat500]

Good evening! I was letting my ‘72 500 warm up this morning but all the sudden stopped after a normal idle. I tried to start it again but no luck. The engine was turning but no spark from the sounds of it.
Upon inspecting the engine bay I found this wire that I cannot determine the correct destination for (picture attached). Any suggestions would be greatly appreciated!

I haven't got access to my car just now, or I could easily tell you. There is a black lead floating about too. But they are possibly lighting and ground leads to the lights cluster to the right hand side at the rear. You can easily check if any light is not working.
I'm not certain, but I think the ignition coil supply is ususally blue, so unlikely this is the cause of the problem.

 

[Toshi 975]

I have worked on two 500s, one being my own, where at some time in their history someone had fitted a “secret” switch as an anti theft device I assume. A wire ran from the positive side of the coil through the switch to earth to short circuit the ignition. I am a great believer in a simple test light to check the low tension circuit to the distributor.

 

[John Nolan]

Truly appreciate the feedback. The two floating wires do not appear to have a purpose (all lights work and was able to get spark after a few more attempts). I ordered a new fuel filter as I wonder if there was a blockage (long overdue). I temporarily inserted a cheap general fuel filter to test but was unable to get it turned over and the throttle felt unusually loose. Would a new filter require throttle adjustment due to a change in fuel flow rate from a different fuel filter?

 

[bugsymike]

Fuel filter should just be a straight replacement, no adjustment needed.
Going back to the non running side, you said you left it idling to warm up?
Any smell of fuel like engine got to rich and choked it's self?
If so once cause fixed, flooding carb or choke lever stuck on, then maybe clean or replace wet plugs.
If not I would just check for spark to start with.

 

[fiat500]

Truly appreciate the feedback. The two floating wires do not appear to have a purpose (all lights work and was able to get spark after a few more attempts). I ordered a new fuel filter as I wonder if there was a blockage (long overdue). I temporarily inserted a cheap general fuel filter to test but was unable to get it turned over and the throttle felt unusually loose. Would a new filter require throttle adjustment due to a change in fuel flow rate from a different fuel filter?

If there had been a very serious blockage in the fuel line, the engine could have stopped running, but more likely if you had been driving at speed. Ideally, you would delete the filter because it presents a weak link in the safety of the fuel supply.
It's worth checking that the throttle cable still has a the tiny C-clip that secures the outer sheath to the bracket. Then if you slacken the small clamp-bolt that secures the solid wire cable, you may be able to pull back any slack on the cable. If you are able to regain a few millimetres you will have a more responsive throttle pedal and a higher top engine RPM.