Hi guy's, Timing belt issue? I changed the Timing belt on my 2013 fiat punto popular 1.2 8v and belt has slipped and has a permanent engine management light on, what is the best solution to rectify this problem. Piston 1 TDC and valves on piston no1 just rocking? Any help would be most welcome
Hi. it's very difficult for the belt to "slip" unless something is significantly wrong, like maybe a failed tensioning spring on the spring loaded tensioner. What is much more likely, especially as you've just done a belt on it, is that the belt has been fitted one tooth retarded and this is a much reported problem here on the forum. So I'd recommend that you first recheck the belt timing. Ok, I know that means a lot of work taking the mount and covers off again but unless you can be absolutely sure your timing is lined up correctly there's no point in mucking about with anything else. A 2013 engine will require timing tools to check this properly as it will have no timing marks due to the cam pulley being unkeyed. Did you use timing tools when you fitted the new belt? if so did you slacken the cam pulley retaining bolt? I ask because it's virtually impossible to fit the new belt with the cam locking tools in place if the cam pulley bolt is not slackened and trying to do so will almost certainly result in the timing ending up one tooth retarded. There's an excellent guide by Andy Monty in the Punto section on how to do the belt change on these later engines - follow the instructions for the VVT engine which also has an unkeyed pulley.
So, I think it likely that that's your problem, however, even with a correctly timed belt change, you can still end up with the EML lit. This can be due to the very sensitive engine ECU detecting that there's a difference in the timing it's previously been seeing between the crank sensor signals and those from the cam sensor. There are two forces acting here, one being simply that there may be a very slight difference between the old and new belts (personally I'm not a great subscriber to this view, I just don't believe there's any measurable difference as long as you buy a good quality belt from a "known name" manufacturer). More likely in my view is that there is a small difference in angular displacement between the cam pulley and camshaft after it's bolt is slackened to allow the new belt fitment and retightening. By the way, this particular "fault" is often recorded by the ECU as a timing fault so if you scan it for stored codes you may well find a misfire code/codes stored which can lead you a merry old dance trying to sort the non existent misfire when it's actually the relearn that's needed.
If you are absolutely certain your crank/cam timing is correct, but the EML/MIL or whatever you want to call it, is still lighting up - typically it won't light as soon as you first start the engine but after a short run - then it's very likely you need to perform a "Phonic Wheel Relearn" (This is what Mike is referring to in his post above. You'll need something like
Multiecuscan or a dealer tool to perform this procedure.
Hope that's helpful and good luck sorting this out - do let us know how it goes won't you.
Edit & PS - Just noticed GrandePunto PL above has posted the link to Andy's helpful guide. Thanks.