Hi all,

Ive been getting an engine flashing light when i'm on the motorway going above 65 mph and around 3500 rpm. This has been going on for a few years. I also get the error codes PO300 and PO302. I had a look inside the engine bay and it seems the breather hose pipe has been cut from the air box. Ive attached some pictures, how likely is it that this is causing the misfiring?

Thanks

Sure it's possible. It'll also leak oil sludge to the spark plugs.

There's another hose at the back of the box check that too. May be disconnected too. Runs to the left side of the intake.

Replace both. You might be able to glue that cut piece of plastic with locktite for example or chemical plastic or epoxy kind of super glue.

Thanks for answering and your suggestions. The hose at the back seems fine and looks alright. I will replace the air box and hopefully that cures the misfiring.

Happened after a cambelt change..?

After timing belt and water pump change if I recall.

But airbox has no agfect on engine running. You can drive vehicle normally without airbox and nothing happen - you can only notice smell from cylinder head and you will reveive no error message. If the engine is missfiring, it will be caused by:
- moved timing after belt replacement (this is my suggestion because it occured after belt replacement)
- wrong spark on any cylinder
- wrong injector on any cylinder

darkdrifter10 said:

After timing belt and water pump change if I recall.

Click to expand...

The ECU sees the new timing 'pings' at a different time to the day before the belt change

The new.. 'unstretched' belt is a fraction shorter.. so the cam signal is now marginally different

It should clear with a PhonicWheelRelearn

Common on Grandes.. with non.expert belt changes

darkdrifter10 said:

After timing belt and water pump change if I recall.

Click to expand...

It will need what is called a phonic wheel realarn procedure carried out
This teaches the ECU the realationship between then cam crank pulleys
As the values can change when the timing belt gets replaced

How would one go about doing this phonic wheel relearn? I have seen previous posts about this and done the revving to 5000 and hasnt fixed it. Do i need to disconnect the ECU/battery first then do the revving?

Also the timings were changed around 2-3 years ago for context. Thanks

Look on the members register.. see if somebody is near you


https://www.fiatforum.com/multiecuscan-members-register/

Plug in amd let the vehicle reset itself

P0302 is missfiring on cylinder 2. P0300 is generic fault error abour missfiring. So check ignition cable to cylinder 2 during night if you see spark somwehere through that cable. If you see sparks, replace that ignition cable (or if car is older replave all 4 cables). If you dont notice any spark, check sparkplug, its color, if its wet, black and compare it with spark plug from cylinder 1. Measure also gap on spark plug from cylinder 2. If everything OK, then injector on cylinder 2 is faulty - you can check sound of each injector by long flat screwdriver and your ear.