MarkoRantala
Member
Hi folks!
This time there is both a question and an answer.
It is a Fiat Punto Dynamic 60 5d mk2/2b 1.2 8v 2004. The problem is known. Go with a mixture that is too lean (Lambda 1.25). And that causes knocking in the engine. The knock is soft, similar to a carbon on piston, early ignition or low octane gasoline.
I must have read a hundred stories about the same problem, but I haven't found a solid answer to the cause.
Now that I understood that it must be a lean mixture so I tested lambda sensor 1 (bank 1) by disconnecting the wires (ecu start giving more gas). That was it. The knocking stopped immediately. And the car got more torque, etc. But what the heck does that?
MAP sensor for test. I used a normal multimeter, needles trough wires and the ventilation pipe of the gearbox. 4 voltages and by sucking the tube the volts dropped normally. So the reason was not in the MAP sensor. The car runs normally otherwise, if you hadn't dealt with cars for 30 years, you would notice that the gas consumption is incredibly low. And knocking, spark plugs white, little jerking. All these on a warm engine. And never at idle, all these under load + accelerating and start about 1800rpm.Gear 1 and 1800rpm is worst.
This is now. Next to find out what the heck could be the reason? I'm going to test the seals with a leaf blower and soapy water before replacing (I use a filter).The most interesting thing is that the better you make the car, the worse it gets, revealing a lean mixture. For example, I changed the plugs, the injector nozzles, the IACV etc.
Quite logical when you think about it. Game tips are gladly accepted if someone has encountered the same.
Ps. I'll tell You, when I found that damn fault. (read if rather than when).
This time there is both a question and an answer.
It is a Fiat Punto Dynamic 60 5d mk2/2b 1.2 8v 2004. The problem is known. Go with a mixture that is too lean (Lambda 1.25). And that causes knocking in the engine. The knock is soft, similar to a carbon on piston, early ignition or low octane gasoline.
I must have read a hundred stories about the same problem, but I haven't found a solid answer to the cause.
Now that I understood that it must be a lean mixture so I tested lambda sensor 1 (bank 1) by disconnecting the wires (ecu start giving more gas). That was it. The knocking stopped immediately. And the car got more torque, etc. But what the heck does that?
MAP sensor for test. I used a normal multimeter, needles trough wires and the ventilation pipe of the gearbox. 4 voltages and by sucking the tube the volts dropped normally. So the reason was not in the MAP sensor. The car runs normally otherwise, if you hadn't dealt with cars for 30 years, you would notice that the gas consumption is incredibly low. And knocking, spark plugs white, little jerking. All these on a warm engine. And never at idle, all these under load + accelerating and start about 1800rpm.Gear 1 and 1800rpm is worst.
This is now. Next to find out what the heck could be the reason? I'm going to test the seals with a leaf blower and soapy water before replacing (I use a filter).The most interesting thing is that the better you make the car, the worse it gets, revealing a lean mixture. For example, I changed the plugs, the injector nozzles, the IACV etc.
Quite logical when you think about it. Game tips are gladly accepted if someone has encountered the same.
Ps. I'll tell You, when I found that damn fault. (read if rather than when).
- Model
- Dynamic 60 1.2v
- Year
- 2004
- Mileage
- 190000
