zmotor
24-06-2016, 11:08 AM
Seat Ibiza 1.4 engine code BKY, genuine ross tech cable was used vagcom version 15.7. Have yet to purchase a low amp clamp hence no current measurments, only have one genuine attenuator hence the separate scope patterns for the injectors.
Initially called for a misfire/juddering when in gear and on the road, first scan revealed:
17766 - Cylinder 2 Ignition Circuit
P1358 - 35-10 - Open Circuit - Intermittent
17519 - Oxygen (Lambda) Sensor Regulation: Bank 1
P1111 - 35-10 - System too Lean – Intermittent
Visual inspection revealed two replaced coil packs some time ago cyl 1 + 2 and two original genuine coil packs 3 + 4, one of the replacements had cracked where the connector joined the coil body (cyl 1) cyl 2 was ok. Wiring looked iffy, lots of electrical tape and the coil earths and power feeds had been heat shrunk and crimped together. Positive feed and ecu signal wire for cylinder 3 had been shorting together.
After sorting out the short on cylinder 3, replacing the damaged coil pack with a bosch unit on cyl 1, cleaning out + re-adapting the throttle body and clearing the codes we were still at the same place. A re-scan revealed no codes, the new coil was swapped to each of the cylinders with no improvement, spark plugs were swapped around too again no improvement.
Checked power, earth and the signal wire for continuity back to the ECU for cyl 2 everything seemed as it should, no resistance in the signal wire for cyl 2 . Customer took the car for a spin and a re-scan revealed:
16686 - Cylinder 2
P0302 - 35-10 - Misfire Detected - Intermittent
16686 - Cylinder 2
P0302 - 35-00 - Misfire Detected
Fast forward to the next day after the customer drove the car around, a scan before starting the cold engine revealed:
16688 - Cylinder 4
P0304 - 35-00 - Misfire Detected
16688 - Cylinder 4
P0304 - 35-00 - Misfire Detected
After starting the cold engine the following was read:
16688 - Cylinder 4
P0304 - 35-00 - Misfire Detected
16688 - Cylinder 4
P0304 - 35-00 - Misfire Detected
17763 - Cylinder 1 Ignition Circuit
P1355 - 35-10 - Open Circuit - Intermittent
After scoping various sensors a re-scan revealed, engine was now warm:
17763 - Cylinder 1 Ignition Circuit
P1355 - 35-10 - Open Circuit – Intermittent
Just before leaving and after carrying out a compression test a re-scan showed:
17766 - Cylinder 2 Ignition Circuit
P1358 - 35-10 - Open Circuit – Intermittent
compression results (pushed for time only two cylinders were done)
cyl 2: 140/140/150
cyl 3: 140/155/155
book value is 145-217?
Both injectors 2+3 OHMd out to 15.6 ohms (reference of 10.5-17)
Cylinder 2 injector (10:1 attenuator was used not 20:1 forgot to change it!!) Injector number 3
3101831019
I have attached scope patterns for cyl 2 + 3 ecu signals to the coil (will need pico software to view)
Dropbox - Coils 2 +3.psdata (https://www.dropbox.com/s/33rus8cakqbme8h/Coils%202%20%2B3.psdata?dl=0)
Dropbox - Injector 2.psdata (https://www.dropbox.com/s/lzbsaglrcx62e68/Injector%202.psdata?dl=0)
Now my question is, cyl 2 injector is clearly faulty and is most likely causing the issue however i cant figure out why the misfire and ignition circuit fault keeps moving cylinders when at first it was fixed to cylinder 2 and then returned to it. I was advised that some misfire detection systems don't always flag the correct cylinder, could this be the case?
Initially called for a misfire/juddering when in gear and on the road, first scan revealed:
17766 - Cylinder 2 Ignition Circuit
P1358 - 35-10 - Open Circuit - Intermittent
17519 - Oxygen (Lambda) Sensor Regulation: Bank 1
P1111 - 35-10 - System too Lean – Intermittent
Visual inspection revealed two replaced coil packs some time ago cyl 1 + 2 and two original genuine coil packs 3 + 4, one of the replacements had cracked where the connector joined the coil body (cyl 1) cyl 2 was ok. Wiring looked iffy, lots of electrical tape and the coil earths and power feeds had been heat shrunk and crimped together. Positive feed and ecu signal wire for cylinder 3 had been shorting together.
After sorting out the short on cylinder 3, replacing the damaged coil pack with a bosch unit on cyl 1, cleaning out + re-adapting the throttle body and clearing the codes we were still at the same place. A re-scan revealed no codes, the new coil was swapped to each of the cylinders with no improvement, spark plugs were swapped around too again no improvement.
Checked power, earth and the signal wire for continuity back to the ECU for cyl 2 everything seemed as it should, no resistance in the signal wire for cyl 2 . Customer took the car for a spin and a re-scan revealed:
16686 - Cylinder 2
P0302 - 35-10 - Misfire Detected - Intermittent
16686 - Cylinder 2
P0302 - 35-00 - Misfire Detected
Fast forward to the next day after the customer drove the car around, a scan before starting the cold engine revealed:
16688 - Cylinder 4
P0304 - 35-00 - Misfire Detected
16688 - Cylinder 4
P0304 - 35-00 - Misfire Detected
After starting the cold engine the following was read:
16688 - Cylinder 4
P0304 - 35-00 - Misfire Detected
16688 - Cylinder 4
P0304 - 35-00 - Misfire Detected
17763 - Cylinder 1 Ignition Circuit
P1355 - 35-10 - Open Circuit - Intermittent
After scoping various sensors a re-scan revealed, engine was now warm:
17763 - Cylinder 1 Ignition Circuit
P1355 - 35-10 - Open Circuit – Intermittent
Just before leaving and after carrying out a compression test a re-scan showed:
17766 - Cylinder 2 Ignition Circuit
P1358 - 35-10 - Open Circuit – Intermittent
compression results (pushed for time only two cylinders were done)
cyl 2: 140/140/150
cyl 3: 140/155/155
book value is 145-217?
Both injectors 2+3 OHMd out to 15.6 ohms (reference of 10.5-17)
Cylinder 2 injector (10:1 attenuator was used not 20:1 forgot to change it!!) Injector number 3
3101831019
I have attached scope patterns for cyl 2 + 3 ecu signals to the coil (will need pico software to view)
Dropbox - Coils 2 +3.psdata (https://www.dropbox.com/s/33rus8cakqbme8h/Coils%202%20%2B3.psdata?dl=0)
Dropbox - Injector 2.psdata (https://www.dropbox.com/s/lzbsaglrcx62e68/Injector%202.psdata?dl=0)
Now my question is, cyl 2 injector is clearly faulty and is most likely causing the issue however i cant figure out why the misfire and ignition circuit fault keeps moving cylinders when at first it was fixed to cylinder 2 and then returned to it. I was advised that some misfire detection systems don't always flag the correct cylinder, could this be the case?