Technical Very frustrating engine cut out !

[Simon1234]

Thanks everyone, fitted the new regulator and went for the best drive ever !!
Problem totally resolved

much appreciated- seasons greet

until the next time

simon

 

[Simon1234]

I makes me shudder every time I see a plastic filter in that position ‘nough said.
In your list of electrical components you have missed out the most likely suspect , the condenser. Any owner running standard ignition should carry at least one spare in their car.
I would have thought that your very experienced Italian mechanic would have been aware of the millions of Fiat 500 cars that ran fine on the original 26IMB carb that is almost identical to the 28IMB that you have but has no return pipe outlet.
however I see you have a late 126 engine where the carb has a solenoid cut off device. I assume that is functioning properly?

Dear Toshi

Could you assist re the “solenoid cut off device”, I cannot find any reference to this in any Manual or on Ricambios catalogue.
Having replaced the coil, voltage regulator and dynamo - frustratingly drove around Canterbury with the engine running sweetly and suddenly the car performed the exact same spluttering power loss and eventually stopping. Then after 10 mins started managed to run 3 miles then the same again. It really does feel like fuel starvation but, I don’t know.
So, the frustration continues ….
Do you think this solenoid could be replaced, I cannot find one, what does it do?, Can it just be disconnected?
or should I just throw the car away !

your reply appreciated

I makes me shudder every time I see a plastic filter in that position ‘nough said.
In your list of electrical components you have missed out the most likely suspect , the condenser. Any owner running standard ignition should carry at least one spare in their car.
I would have thought that your very experienced Italian mechanic would have been aware of the millions of Fiat 500 cars that ran fine on the original 26IMB carb that is almost identical to the 28IMB that you have but has no return pipe outlet.
however I see you have a late 126 engine where the carb has a solenoid cut off device. I assume that is functioning properly?

 

[Toshi 975]

Dear Toshi

Could you assist re the “solenoid cut off device”, I cannot find any reference to this in any Manual or on Ricambios catalogue.
Having replaced the coil, voltage regulator and dynamo - frustratingly drove around Canterbury with the engine running sweetly and suddenly the car performed the exact same spluttering power loss and eventually stopping. Then after 10 mins started managed to run 3 miles then the same again. It really does feel like fuel starvation but, I don’t know.
So, the frustration continues ….
Do you think this solenoid could be replaced, I cannot find one, what does it do?, Can it just be disconnected?
or should I just throw the car away !

your reply appreciated

I don’t think you will find any manuals that cover the solenoid type carb that I suspect is a Weber 28SIA. They were on the much later cars as were the cylinder head that you have with the additional markings above the 650. I don’t think that the solenoid is your problem somehow, more likely to be ignition. Can you get pictures of your coil and distributor?

 

[Simon1234]

I don’t think you will find any manuals that cover the solenoid type carb that I suspect is a Weber 28SIA. They were on the much later cars as were the cylinder head that you have with the additional markings above the 650. I don’t think that the solenoid is your problem somehow, more likely to be ignition. Can you get pictures of your coil and distributor?

Hi here are the photos of the carb

The other option is to replace it.
What would be the best and most reliable option, it’s not a race car, I want a good solid carburettor
Remember there is a 126 engine in my car.
I replaced the coil last week
Here is the distributor (inside and out) I noticed the wear through on the red cable
Just to recap the car started perfectly, i drove say 6 miles at reasonable speed ( dual carriageway), suddenly when all warmed up the car looses power, just like the fuel has run out, it then recovers for 200 yards, then does the same, eventually I’m on the side of the road with my foot full on the accelerator and the car is spluttering on a lumpy tick over, them it stop.
After 5 mins it starts, and then stops, it then re starts but it won’t accelerate splutters and eventually dies.
After 15 minutes it starts and after 1 mile it’s the same as above.
I have replaced; fuel lines, fuel pump, dynamo, coil, cleaned; all filters ( inc inside petrol tank).
it’s driving me bonkers - all assistance hugely appreciated

simon

 

[Toshi 975]

Hi here are the photos of the carb

The other option is to replace it.
What would be the best and most reliable option, it’s not a race car, I want a good solid carburettor
Remember there is a 126 engine in my car.
I replaced the coil last week
Here is the distributor (inside and out) I noticed the wear through on the red cable
Just to recap the car started perfectly, i drove say 6 miles at reasonable speed ( dual carriageway), suddenly when all warmed up the car looses power, just like the fuel has run out, it then recovers for 200 yards, then does the same, eventually I’m on the side of the road with my foot full on the accelerator and the car is spluttering on a lumpy tick over, them it stop.
After 5 mins it starts, and then stops, it then re starts but it won’t accelerate splutters and eventually dies.
After 15 minutes it starts and after 1 mile it’s the same as above.
I have replaced; fuel lines, fuel pump, dynamo, coil, cleaned; all filters ( inc inside petrol tank).
it’s driving me bonkers - all assistance hugely appreciated

simon

Should there be pictures of the distributor? I can’t see any.
for your requirements I would say you are best sticking with a standard Weber 28IMB carb. Whilst I could quite happily sell you a refurbished replacement carb I am still thinking that the problem may be ignition based.
is it a twin spark coil you have?
does the distributor have a conventional distributor cap.

 

[Simon1234]

Should there be pictures of the distributor? I can’t see any.
for your requirements I would say you are best sticking with a standard Weber 28IMB carb. Whilst I could quite happily sell you a refurbished replacement carb I am still thinking that the problem may be ignition based.
is it a twin spark coil you have?
does the distributor have a conventional distributor cap.

 

[Simon1234]

The carburettor

 

[Simon1234]

The distributor

no idea what happened to the first lot of photos

 

[Toshi 975]

OK I can see you have an Accuspark type ignition. They have been known to break down on some occasions. But before you throw the baby away with the bath water you need to do some tests to eliminate fuel or ignition. Ignition is probably easiest to check.
When the car refuses to start do you have power on the low tension side coming out of the coil? This could be tested with a multimeter or a simple 12v test light.
if that is OK do you have power and a spark at the plugs? For about a £1 you can get a simple spark tester which would go onto the plug and the ht lead go onto that. The tester will light up when the power passes to the plug.

 

[fiat500]

The distributor

no idea what happened to the first lot of photos

I think your distributor cap is damaged, especially around one of the inner electrodes.

It's not obvious to me how the red and the black cables are exiting the distributor; are they trapped under the cap? As you say, that damaged wire will definitely be a part of the problem.

I would fit a new distributor cap and rotor arm, sort out the damaged wires with replacements or very well cleaned up and reinsulated and thoroughly clean up inside the distributor, checking that it's all set up as specified by the manufacturer.

Personally I would also go back to the original contact-breaker, but the main thing that's obvious is the cap.

 

[Simon1234]

Dear All contributors,

Firstly, a massive thank you for all your assistance. My first interaction with this site and a fabulous response.

In conclusion to the “frustrating engine cut out“, it WAS the distributor.
On close inspection it was worn and failing everywhere.
This was replaced with the https://www.ricambio.co.uk/complete-123-electronic-distributor-classic-fiat-500-126. Which was an easy fit ( note the set up LED is inside under the cap, not stated in the instructions).
Having already replaced the coil and other bits (I know I threw money at the problem). Has resulted in a smooth and more powerful engine response.

New as I am to this car and the world of the classic 500 I was happy to replace a few high wear parts anyway. All as part of my journey towards enjoying driving and using the car, rather than waiting for these parts to fail on my when I least expect it and being frustrated and disappointed. Don’t think im deluded enough to think the little bus isn’t going to mess me about, of course not but, we’re getting the measure of each other !

thanks again- Simon

I’m going to post a new thread “why does the red light on the dash with “g” in it stay on them the engine is warmed up ?”

 

[Simon1234]

 

[the hobbler]

The problem with the 500/126 engine is that the distributor is right in the path of the 'cooling' air from the engine, and neither the electronic ignitions (ALL types) or condensers (when 'points ignition is retained) like heat---sustained 100C seems to be the 'make-or-break' temperature. Modern condensers are very cheaply made---I always advocate using the 'Swiftune Competition' condenser. (a) it is made to a high standard for use by competition cars where the rules state that the original ignition system must be retained (even GT 40s) and, (b) it has long feed and earth wires, which allow one to fit it up by the coil, out of the way of the hot air from the engine. I have suffered a 'end-of-life' electronic ignition---it would run for about 10 minutes and then the engine ran like a dog---allow it all to cool off, and it would again run for about 10 minutes before going through the same scenario. It took me nearly 4 hours to get home from a trip that had taken just under a hour to get there! Eventually, I took the ducting off the o/s (distributor side) and designed and fitted a small 'air-dam' to stop the hot air going over the distributor. It makes about 10C difference and keeps the distributor UNDER the 100C mark, which is when, as I previously mentioned, electronic ignition and condensers start to wilt.

Something that might help people with the "Accuspark" ignition module---should the unit go faulty, if you send the faulty unit back to Accuspark, along with a copy of your purchase invoice, EVEN WHEN IT IS OUT OF WARRANTY, they will supply anew unit for just £20