Hello everyone.

I would like some advice please.

My grande punto 1.2 8v 2006 cuts out when warm and then struggle to restart. If it restarts at idle it cuts out again.
Engine light on, did the scan and the crankshaft sensor was the problem.
It was replaced but didn't fix the problem.
The obd scan says crankshaft sensor again. I did but a second one, thinking the first was faulty but nothing changed.
The rev count sometimes work sometimes doesn't, but the car can't be driven at the moment because it won't start anymore.
I can only start the car disconneting the crankshaft sensor, and doing so the car never cuts out. If i plug it in it cuts out immediately if at idle.
Shall i buy a new sensor directly from fiat?
Could it be something to do with the wiring or the sensor connector?
Ah, ecu also have been changed after autoeletrician advice, waste of money didnt solve anything. Timing checked, belt not even one year old.

Anyone had a similar experience?
Need help!

Thanks

Easy one (probably).
1. Year 2006 = check "earthing points" for corrosion (Search the term, there is a Guide) and other wiring (starting with the TDC sensor plug and cable, obviously).
2. Fuse/Relay box in the engine bay. Also corrosion (it eats the copper inside the insulation of the individual wires).
3. Then charging (alternator and the water drain pipe above it - old type was bad, too short - years 2006 to 2010 or so) and battery condition. Due to bad ground and/or supply (+) issues, ECU cannot see the TDC signal properly (doesn't matter much, that TDC sensor is "floating" - in electronics engineering slang - or was in Punto1 & 2).
4. Multiple brand new faulty TDC sensors and/or ECU is very unlikely. Last thing(s) to worry about.
Although symptoms are classic (for older Punto generations): it will crank but not start when hot. But should not die! Subtle difference.
5. Maybe it's the other sensor issue, like MAP (it measures the temperature too) or coolant temp.?

When you scan it it comes back crank sensor, yes. So the ECU is seeing a problem in that circuit. You've replaced the sensor twice? Unlikely that two new sensors are going to be faulty so it's got to be in a plug connection or the wire. Looking in my crystal ball I see a session of continuity checking in your immediate future!

The crank sensor is quite exposed to the elements down there so have a really good look at the plug for verdigris. The condition of the inside of the connector on the old sensor might give some clues - ie is it nice and clean?

Good luck, tracking down this sort of thing can be frustrating and time consuming but often is cheap to fix.

Thanks for your help.
I also thought it could have been a wiring problem.
In fact I did order a new 2way connector already wired from the internet. Now I have to find someone that can do the job.

It's strange that this happened after not long from the last service, where i also changed the coolant liquid and a breather hose.

I ll let you know how it will end. I hope not to the scrapyard!

Ah by the way all the earth connections also have been checked and the battery also.
I will investigate further checking the fuse box and the charging.

I didn't mention before one thing that it could be relevant.
Two months ago the car did overheat. I stopped, refilled, let it cool off and took it to my local garage. There was a leak in the coolant system coming from the core plug behind the engine.
The core plug was obviously replaced and soon after this other problem have arisen.

As you mentioned ealrier it could be also temperature related..

I might try to change the coolant temperature sensor also to see if there are improvements.

I ll keep you informed.

Thanks

So the wiring was probably disturbed during the "engine block core plug" job.

Get the interface cable (ELM327 or something like that) and FES/MES program, to read the codes and parameters yourself. Then decide what to buy (or not) next (you will see the sensors misbehaving etc.).

To learn more watch this guy: https://www.youtube.com/c/ScannerDanner/videos (he's a "real-deal")!

Very much appreciated! Thank you!
I will investigate.
Which misbehaving sensors you are referring to specifically? Sorry but i am not an expert in this field.

I think i ll have to hire a good autoeletrician..

You've mentioned "coolant temperature sensor" - so for example you can check the readings (in "MES" - Multi ECU Scan) before you order a part.
Point is: "don't be a parts changer" (like the ScannerDanner's YT channel motto).

Try to diagnose (in the future). Take small (baby)steps and learn.
For now, of course, outsource the job (if you are in a hurry).