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Technical Phonic wheel relearn isn't....

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Technical Phonic wheel relearn isn't....

puntodeltathema

puntodeltathema

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Hi folks

Just done a cambelt on a 500 1.2, early Euro 6. I used the proper tools, slackened the cam pulley etc. It started up fine, ran very sweetly at idle up to temperature (I did the water pump too so was bleeding out the air for some time).

I've done a few now and this is the first time an engine management error has been reported during the run up afterwards (at idle). OK, methinks phonic wheel relearn, no problem...

However, it doesn't seem to work. The initial reset using Multiecuscan appears to work OK. (I do this with key on and engine not running - presume that is correct). I then turn off, leave it for sixty seconds, start up and do the 3 revs (fairly immediately) but it doesn't seem to be eliminating the error.

First time I tried it allowed me to rev to 6000 rpm but on subsequent attempts it wouldn't let me rev past 5000 (the EML changed from steady to flashing at this point).

Any thoughts? Does one need to let the car idle for a while? I have been doing the procedure with the car hot and doing the revs immediately - do I need to do it from cold, allow it to warm up and do the 3 revs then?

In short, is it fairly foolproof or is there a very precise procedure or sequence, some of which I'm not doing right?!

One thing I noticed in MES for the Euro 6 1.2/1.4 is that there are loads of similar but different procedures - phonic wheel relearn, replacement of timing sensor or cam, replacement of RPM sensor or distribution belt.... I've tried the first two but no difference.

I also have a P0016-76 (cam shaft assembly position) error but I'm assuming that's just because the new timing is different from previously.

Tomorrow I will strip down the engine again (sigh) to check the timing hasn't slipped but thought I would check the collective wisdom before I do....

Thanks!

Nick
 
Timing is OK (even allowing for the fact the Sealey tool only seems to fit in the eccentric slot in the cam when it's 180 degrees "out" - that threw me for a bit though it is exactly 180 degrees out so it should be fine in theory - and it aligns visually in the "proper" position, even if I can't get the tool in because the base piece is too thick).

So it can only be engine management. When I've got it back together I think I will try the Euro 5 phonic wheel learn.

Those who have done it, do you do the MES "execute" from dead cold after reconnecting the battery?

Nick
(PS thanks @veresecrazy I'll check out the Punto section)
 
puntodeltathema said:
Timing is OK (even allowing for the fact the Sealey tool only seems to fit in the eccentric slot in the cam when it's 180 degrees "out" - that threw me for a bit though it is exactly 180 degrees out so it should be fine in theory - and it aligns visually in the "proper" position, even if I can't get the tool in because the base piece is too thick).

So it can only be engine management. When I've got it back together I think I will try the Euro 5 phonic wheel learn.

Those who have done it, do you do the MES "execute" from dead cold after reconnecting the battery?

Nick
(PS thanks @veresecrazy I'll check out the Punto section)
Click to expand...
Rotate the crank one full turn and the cam rotates 180 degrees. Crank tool fits, and then so does the cam tool. So probably nothing wrong there, with tool or engine. Timing is set with pistons half-way up the bores, to avoid valve/piston togetherness, so it is not TDC.
 
puntodeltathema said:
Hi folks

Just done a cambelt on a 500 1.2, early Euro 6. I used the proper tools, slackened the cam pulley etc. It started up fine, ran very sweetly at idle up to temperature (I did the water pump too so was bleeding out the air for some time).

I've done a few now and this is the first time an engine management error has been reported during the run up afterwards (at idle). OK, methinks phonic wheel relearn, no problem...

However, it doesn't seem to work. The initial reset using Multiecuscan appears to work OK. (I do this with key on and engine not running - presume that is correct). I then turn off, leave it for sixty seconds, start up and do the 3 revs (fairly immediately) but it doesn't seem to be eliminating the error.

First time I tried it allowed me to rev to 6000 rpm but on subsequent attempts it wouldn't let me rev past 5000 (the EML changed from steady to flashing at this point).

Any thoughts? Does one need to let the car idle for a while? I have been doing the procedure with the car hot and doing the revs immediately - do I need to do it from cold, allow it to warm up and do the 3 revs then?

In short, is it fairly foolproof or is there a very precise procedure or sequence, some of which I'm not doing right?!

One thing I noticed in MES for the Euro 6 1.2/1.4 is that there are loads of similar but different procedures - phonic wheel relearn, replacement of timing sensor or cam, replacement of RPM sensor or distribution belt.... I've tried the first two but no difference.

I also have a P0016-76 (cam shaft assembly position) error but I'm assuming that's just because the new timing is different from previously.

Tomorrow I will strip down the engine again (sigh) to check the timing hasn't slipped but thought I would check the collective wisdom before I do....

Thanks!

Nick
Click to expand...
I feel for you doing this in the heat! I did mine last summer in 30c ..in the garage it felt like 40c 😂 I’m confused by all the options you have for the re learn! I only had one option I followed the instructions and it was fine
Yes I did mine from cold but would that make a difference?
I don’t understand euro 6 ? Is this an international thing? (Still learning) as I’ve said 😂
 
Periodic cambelt replacement is a routine service item on pretty much any car with a belt driven camshaft and you'd expect the manufacturer to have put in place a simple, foolproof procedure for carrying this out without needing special tools and recalibration software. Unfortunately this doesn't seem to be Fiat's philosophy and I really can't think of any simple basic engine where the procedure is as problematic as this one. The infinitely variable cam sprocket positioning means special tools are essential (if using the sprocket loosening method) and gives endless opportunities to get into difficulties and create problems with what was previously a perfectly sound, working engine.

I've lost track of the number of posts from folks who've had problems with rough running and mistimed engines after belt replacement - there must be hundreds now. Whilst I suspect some of these are the result of poor working practices, there have also been many issues reported by folks with excellent mechanical skills, qualifications and experience.

What I'm basically saying is this isn't your fault; it's Fiat's fault for designing an engine with such a complicated and confusing belt replacement procedure.

And whilst I'd never encourage anyone to ignore the manufacturers recommendations on belt/water pump replacement, it's interesting that we almost never see reports here of actual belt failure (on the petrol engines at least - chain failure on high mileage diesels is a different story). Problems of poor running after belt replacement are at least a hundred times more common.
 
jrkitching said:
Periodic cambelt replacement is a routine service item on pretty much any car with a belt driven camshaft and you'd expect the manufacturer to have put in place a simple, foolproof procedure for carrying this out without needing special tools and recalibration software. Unfortunately this doesn't seem to be Fiat's philosophy and I really can't think of any simple basic engine where the procedure is as problematic as this one. The infinitely variable cam sprocket positioning means special tools are essential (if using the sprocket loosening method) and gives endless opportunities to get into difficulties and create problems with what was previously a perfectly sound, working engine.

I've lost track of the number of posts from folks who've had problems with rough running and mistimed engines after belt replacement - there must be hundreds now. Whilst I suspect some of these are the result of poor working practices, there have also been many issues reported by folks with excellent mechanical skills, qualifications and experience.

What I'm basically saying is this isn't your fault; it's Fiat's fault for designing an engine with such a complicated and confusing belt replacement procedure.

And whilst I'd never encourage anyone to ignore the manufacturers recommendations on belt/water pump replacement, it's interesting that we almost never see reports here of actual belt failure (on the petrol egines at least - chain failure on high mileage diesels is a different story). Problems of poor running after belt replacement are at least a hundred times more common.
Click to expand...

To be fair, Fiat has an old warhorse engine designed to run on paraffin, and the ever-more stringent EU regs are forcing them to continually make it run cleaner and cleaner. Eventually it'll run on water and just emit unicorn farts... but that'll take a bit more engineering.

The additional doodah on the camshaft is probably the best they could do on the budget they were provided. Fiat seems to either never have any money, or be utterly stingy with it but the engineering probably had to be completed on 2' & 6d or something. We saw the Euro VI fly-by-wire maps weren't great initially... so it doesn't strike me as a well-funded, comprehensive re-work.

It'll be interesting to see how long the 1.2 donkey lasts; the new 1.0ltr Firefly might displace it (and fill in for the TA) eventually, as the last of the dino-engines... but I suppose Fiats will all be nuclear powered in future and so they didn't want to sink a shed-load of money into the old engine, when the emissions and fuel of the future was still evolving.


Ralf S.
 
Thanks....

I don't think the VVT sprocket is the issue - you can basically have that in any position. The problem is the relationship between the cam sensor and crank sensor signals (the latter generated in conjunction with its "phonic wheel") and what the engine management will accept as a change from the parameters it holds. If it's beyond a certain tolerance (including putting what seems "wrong" timing back to "correct") then it doesn't appear to accept it, phonic wheel relearn or not (at least with MES). You get a persistent P0016 crank-cam correlation error (camshaft assembly position) which also puts you into limp mode (and you can't do a relearn in limp mode even if you wanted to....)

This seems to be a Marelli injection peculiarity. I don't think the Bosch managed engines have such a thing - I presume they just pick up whatever the current signals are and work with them. Interestingly (from experimentation) the Marelli system cam sensor doesn't seem to be continuously monitored - it only appears to be read periodically (if you unplug it, nothing happens until eventually it detects it isn't there)....

Still working through this but I think my learning point from all this may be to always note (and remember!) the position of the crank (using the lock tool to determine its relationship to "true" timing) before removing the old belt. And set the new belt up not to be perfectly timed, but timed as the old one was..... and it's surprising how many old belts (at first change) are not timed absolutely correctly. Which if they don't stretch, means they must be put on a bit off at the factory.....

Which all seems to be an argument to not use the lock tools at all, and just use the "tippex" method!

Unless someone out there has a magic software procedure to reliably get an engine to recognise a new cam/crank relationship. But the MES procedures do not seem to do this. (Maybe official Fiat software does?)

I suspect this issue might also be more acute on the Euro 6 engines possibly because the parameters are all a bit tighter for emissions reasons. (I've merrily done Euro 5 engines before without encountering any of this, so my world has been rocked a bit recently!).
 
Ralf S. said:
To be fair, Fiat has an old warhorse engine designed to run on paraffin, and the ever-more stringent EU regs are forcing them to continually make it run cleaner and cleaner. Eventually it'll run on water and just emit unicorn farts... but that'll take a bit more engineering.

The additional doodah on the camshaft is probably the best they could do on the budget they were provided. Fiat seems to either never have any money, or be utterly stingy with it but the engineering probably had to be completed on 2' & 6d or something. We saw the Euro VI fly-by-wire maps weren't great initially... so it doesn't strike me as a well-funded, comprehensive re-work.

It'll be interesting to see how long the 1.2 donkey lasts; the new 1.0ltr Firefly might displace it (and fill in for the TA) eventually, as the last of the dino-engines... but I suppose Fiats will all be nuclear powered in future and so they didn't want to sink a shed-load of money into the old engine, when the emissions and fuel of the future was still evolving.
Click to expand...
The 8v FIRE engines have already been consigned to history as I understand it.

So the "unicorn fart" design department has been stood down :D
 
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