Are you aware of any recent maintenance?
If distribution belt was replaced and timing not correct this can also lead to a P0101 error:
source in Dutch:

https://www.woutbouman.nl/blog/fiat-grande-punto-slaat-soms-spontaan-af

Hi, thanks for the reply. I did the timing in the summer using the timing tools and it has been running ok until now, but I'll get the strobe light out again to check. I'll also look for inlet leaks. Any other suggestions?

Hi both

The GP fire motors also need the signals from the top and bottom pulley sensors aligning..

The minor changes of 'time' with a different belt... can flag errors at high
Rpm.

Plenty of info on here.. SEARCH is very good

Charlie

Hi, I've checked with the strobe light and at idle the notch in the flywheel is not ligning up with the 0 degrees tooth, which I thought it should. Is that right? Thanks.

Aren't you confusing timing and ignition ?

Ignition (strobe flash) normaly occurs BEFORE end of compression stroke (DTC), so when the light flashes, you should see the mark on the rotating flywheel before it reaches the 0 degree mark on the housing...

BRs, Bernie

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Thanks for the reply Bernie. I thought that the idea of the notch and the marks were to show where the pistons were when ignition occurred and was thinking that ignition was at TDC at idle. However what you are saying makes sense, as I set timing using the tools and an ECU error I had before stating the cam/crank were out of sync disappeared after I set the timing. Ok, so if the strobe is not at TDC is it at some specific degree before that I can check, otherwise I'm not sure how to check the timing without taking the engine mount/cam covers etc off again and checking again with the tools that nothing has altered? The car seems to run ok, apart from the P0101 error issue and my wife thinking it's using a lot of petrol (which I suppose would make sense with the P0101). Thanks again.

Hi Jon,

on those engines, the ignition point is determined by the ECU after computing some informations from various sensors:

- piston position (crankshaft sensor)
- piston number (camshaft sensor)
- engine load (throttle sensor)
- engine speed (crankshaft)
- other, like water temp, atm pressure ...

Typically the firing angle before TDC would be 10 - 15° @ idling. To check this a good quality strobe light is equipped with a de-phaser that would add some time between the spark detection and the actual flash. The idea is to adjust this added time so both marks on the flywheel and the 0° notch are facing when the flash strobes. The position of the adjustment knob will then show the correction angle.

So in short: the crank tells when to spark (arrival near TDC) and the cam tells which cylinder to start (1 or 4, the others being computed using crank teeth).

The timing itself (valve opening) is only defined by the sprocket and pulley relative position (without VVT): both locking tools at crank and cam shafts MUST engage together when the engine is in set position, with the belt on and properly tightened. On GPs engines, this is when all 4 pistons are at the same position: mid-stroke ...

BRs, Bernie

If someone here helped You fix -or better, understand- your issue, hit the thanks icon @ bottom right corner, it's free and makes us feel helpy ;-)

Thanks Bernie. I think I've resolved the issue as one of the vacuum pipes had a split in it and I replaced the air filter at the same time as the pipe. So far, no repeat problems.

Always check the simple things first...

Thanks for the update Jon, job well done !!

BRs, Bernie