Hi all, this is my first post here!

I've got an mk2 Punto 1.2 8v that won't rev past 3000rpm. It started last week after not being driven for a few weeks. It starts and idles fine, and sounds smooth like it normally does but when I hold my foot on the accelerator it just revs up and down between idle & 3000rpm, the MIL light comes on and goes out once the car returns to idle.

I got RAC out who plugged their scanner in which read P0302 (misfire on cylinder 2), he changed the spark plugs and HT leads because they were very worn but it made no difference. He said the ECU had probably been spiked and needed replacement, he also said he was getting electric shocks from touching the engine bay before the spark plugs were changed. I had the car towed to a friend's house who knows more than I do about cars, he plugged his scanner in and got PO351/2 (ignition coils), the misfire code is no longer there. Both coil packs have now been changed and still no difference, the PO351/2 codes lingered and after a bit of research, it did suggest that this is a symptom of a failed ECU, so I placed an order on Friday for a remanufactured 'virgin' unit costing £120.

I've now got the registered version of Multiecuscan and the PO351/2 codes have disappeared (even though I don't recall clearing them) and no errors are detected. I've been looking at the data under the 'parameters' tab. Two things that stand out are: "Throttle position" gives a blank % reading, and "Phonic wheel status" changes to "faulty" when I rev the engine but returns to "OK" when the car is idling.

From reading other threads on this forum this seems to relate to the cambelt? I've tried to do the self-adaptation reset and phonic wheel learn reset but on all occasions it just said "conditions not suitable" or something similar. In hindsight though I think I may have been doing it wrong, I had warmed the engine up until the fan kicked in and then pressed "execute" on the procedures while the engine was running but I think I should have run the procedure first and THEN started the engine and let it warm up before revving to 5000rpm 3 times. Can anyone confirm?

Also, before connecting to the ECU with MES, there are 3 different 'modules' in the list, and I'm wondering if I was connecting to different ones and if that would explain the error codes seemingly disappearing on their own without being cleared? I've attached some screenshots of the data in MES, the first 3 are with the car idling, the fourth is when I rev it and the fifth is the 3 'different' ECUs in the MES menu.

The new ECU is being delivered tomorrow but I'm really not convinced it will solve the problem. I'm trying to avoid installing it until other issues have been ruled out because once it's fitted to this car, I probably wouldn't get a full refund on it because it would have to be reprogrammed and "virginised" by the company before being resold. But with no other error codes being stored I'm not sure where next to go with this.

Can anyone offer any advice or share their thoughts?

Many thanks in advance!
Andrew

I think the fault is the distributiin being out of sync. The belt jumped some teeth and this is why you cannot rev past 3000 RPM. At least this was the case many times before, you should check the distribution alignment.
Regarding the phonic wheel learn you did it right, kt should execute and then start the engine and rev it up to 5000 RPM 3 times.
I suspect there must be another problem at yours than usual, not reving past 3000 RPM (usual being the distribution out of sync) and that is the throttle positioning sensor. You say it stays at 0%, it should stay that only on idle, if it stays like that when you press the acceleration pedal is means it is at fault and that is why you cannot rev past 3000 RPM. Because the ECU does not "see" the throttle being open (sensor sending the reading of 0%) and so it not gives gas.
LE: after looking at the pics you've attached I see that "throttle angle" gives you the correct reading like 0.2 deg on idle and 25 deg on rev so the fault remains to be the distribution.

If I am reading your post correctly then I have seen this before and the cause was the crankshaft position sensor.

Cheap and easy to replace.

Do check the cam belt and valve timimg as mike suggests too.

Let us know.

Cheers

Jack

Yes, by the term distribution I ment the timing belt that synchronizes the rotation of the crankshaft and the camshaft so that the engine's valves open and close at the proper times during each cylinder's intake and exhaust strokes.
Thank you Jack.
I used the term "distribution" because this is the usual term used in my language, Romanian.
Sorry, my bad as this term is not usual used in English.

Thank you both for your replies. I'm glad we seem to be singing from the same hymn sheet, it was the other fault codes that sent me on a wild goose chase. When you say check the cam belt and valve timing, is there anything specific I need to look out for i.e will it be obvious that something is wrong?

Also I am thinking of trying to do the phonic wheel reset again now that I know it should have been done before starting the engine. But would this have any effect if the belt is many teeth out of sync? If doing this got the car working I would be looking to get the belt replaced anyway, I am basically just trying to completely rule out a faulty ECU before I send the replacement back. The bit I am confused about is why there are no error codes stored relating to any sensors or the cam belt?

Thanks again for your help.

Change the crank position sensor.
It's cheap and easy job.

See If the engine will then run well enough to perform the phonic wheel relearn.

Then look at the guides how to change cam belt that will show how to check valve timing

Faulty crank sensors rarely set a fault code it's just the way it is.

Ps if you live anywhere with mice/squirrels check one hasn't filled your air filter with hay and nuts
Fuel tank full?

I'll try and get that checked later this week, the car isn't with me at the minute.

Can't post URLs yet until I've had 5 posts, but is this the sensor I need? - ebay.co.uk/itm/271525596881 (hope this doesn't upset the mods!)

My mate had a look in the intake to check for mice etc but it's clear and engine does the same thing even with the cover removed. Tank just under half full but as the car did less than 200 miles last year it's not had petrol put in for about 9 - 10 months! It gets turned over regularly just to keep the battery alive.

Thanks again.

Sorry, read that wrong. Is this the correct part? - www.ebay.co.uk/itm/233779208448

PoorlyPunto said:

Sorry, read that wrong. Is this the correct part? - ebay.co.uk/itm/233779208448

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That is a crankshaft position sensor, yes, but check yours before you buy one. Maybe you'll find the part no. on yours and search one like that because the one in the link you've put looks different. At mine, Punto 1.2 8V 2006, the sensor does not have any cable, like the one in your link, it's just sensor and on it the plug for the cable.
It looks kind of like in this picture

Mike1alike said:

That is a crankshaft position sensor, yes, but check yours before you buy one. Maybe you'll find the part no. on yours and search one like that because the one in the link you've put looks different. At mine, Punto 1.2 8V 2006, the sensor does not have any cable, like the one in your link, it's just sensor and on it the plug for the cable.
It looks kind of like in this picture

Click to expand...

Thanks, I'll check the part number before ordering anything. My mate spoke to a mechanic today and showed him a video he took of the car doing what it's doing, and he suggested it could also be the MAP sensor, what do you guys think?

Mike1alike said:

Yes, by the term distribution I ment the timing belt that synchronizes the rotation of the crankshaft and the camshaft so that the engine's valves open and close at the proper times during each cylinder's intake and exhaust strokes.
Thank you Jack.
I used the term "distribution" because this is the usual term used in my language, Romanian.
Sorry, my bad as this term is not usual used in English.

Click to expand...

You are correct

The ePER refers to it as 'distribution'

In UK english.. we have only just stopped using the phrase for Ignition

Where a 'Distributor' was in use for 100 years..
Distributing the sparks down the HT leads

I don't think you will have any luck being able to perform a phonic wheel relearn on a 2002 car as far as I know this is only applicable to the latest euro 5 and 6 engines with variable valve timing
A 2002 car shouldnt have this as far as I'm aware it starts around 2008-2009 with the 69 hp engine's

chris3234 said:

I don't think you will have any luck being able to perform a phonic wheel relearn on a 2002 car as far as I know this is only applicable to the latest euro 5 and 6 engines with variable valve timing
A 2002 car shouldnt have this as far as I'm aware it starts around 2008-2009 with the 69 hp engine's

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No, it is not like that. It is not applicable only to euro 5 and 6 engines as I've applied it on 2006 euro 3.
I think Andrew couldn't perform phonic wheel relearn only because he tried it with engine alredy turned on, hence the error "conditions not suitable". I really couldn't remember that detail that the engine must be turned off, but it makes sense. I figured it out while doing it and just forgot about it as there was no problem anymore.

Mike1alike said:

No, it is not like that. It is not applicable only to euro 5 and 6 engines as I've applied it on 2006 euro 3.
I think Andrew couldn't perform phonic wheel relearn only because he tried it with engine alredy turned on, hence the error "conditions not suitable". I really couldn't remember that detail that the engine must be turned off, but it makes sense. I figured it out while doing it and just forgot about it as there was no problem anymore.

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Be able to apply it and it being needed are two different things did you have an issue with the timing being out?


Certainly not heard of an issue with the older not variable timing engines but perhaps I've missed it?

chris3234 said:

I don't think you will have any luck being able to perform a phonic wheel relearn on a 2002 car as far as I know this is only applicable to the latest euro 5 and 6 engines with variable valve timing
A 2002 car shouldnt have this as far as I'm aware it starts around 2008-2009 with the 69 hp engine's

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https://www.fiatforum.com/showthread.php?t=91258

Phonic wheel relearn has been around long before variable valve f.i.r.e engine came along.

Hi all, I did the self-adaptation reset and phonic wheel relearn yesterday but no improvement. The engine light is also flashing now because I can't get the revs up to 5000rpm to complete the reset. The revs seem to have dropped further over the last week, it now cuts out about 2500 initially but once the engine has warmed up it cuts out around 2000-2200. Crank sensor on order and I'll update this thread when it arrives, hopefully mid-week. I checked the part number and it matched up with the one I linked to with the wire attached (46774532).

Have you removed the spark plugs for comparison?

Thats a very odd running condition isnt it

I haven't checked them since the RAC guy replaced them 2 weeks ago, should I? The problem definitely isn't making much sense to me, especially now there's no error codes being stored.

PoorlyPunto said:

I haven't checked them since the RAC guy replaced them 2 weeks ago, should I? The problem definitely isn't making much sense to me, especially now there's no error codes being stored.

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Enough petrol in tank?

jackwhoo said:

Enough petrol in tank?

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Half a tank.