Skoda octavia overfueling

[thebigman]

Hoping for some help with this. origional dtc 16556 fuel trim system too rich 17700 map controlled eng cooling thermostat open circ, 16500 engine coolant temp sensor implausible signal, 17658 fuel level low. Initial inspection showed a conector broken off the thermostat and the plug hanging disconected. whoever did this also disconected the ac fan and cut the feed to the main cooling fan and rigged it to run via a four pin relay via a feed taken off the alternator. Got a new housing from skoda complete with a new temp sensor and reinstated the fan wiring so everything back how it should be cleared dtc's. car started and ran till warmed up started to miss warning lamp back on strong smell of fuel smokey exhaust. This time multi cyl misfire 16687 no3 misfire 16685 no1 misfire 16684 maf low output. Traced the maf fault to the air intake hose had a small split at the breather hos so replaced that. Misfire is down to the spark plugs being totally satured with fuel cleaned them up and the car ran ok till they fouled up again. the maf code hasnt returned but the misfire keeps coming back due to the amount of fuel its firing through.

its a 1600, 2003 BFQ engine

thebigman

[Ashraf6119]

Hi

What is the Coolant Temperature readings in live data showing when Engine is cold from start and as when its warmed up still when it starts to misfire at that point.

Also make sure the coolant temperature sensor you have replaced it should be Green Colour and not back one.


Ash

[dimitar]

Things to check:
1. Live data from maf
2. Live data from MAP
3. ECT sensor readings live data
4. Fuel pressure
5.Sticky injectors (check for leaks)
6. Air intake clogged (air deficit)
7. Faulty ECU
8. Air temp sensor (not much important)
9.O2 sensor live data (very important if wide band sensor used with 5 or 6 wires)

[thebigman]

Hi

What is the Coolant Temperature readings in live data showing when Engine is cold from start and as when its warmed up still when it starts to misfire at that point.

Also make sure the coolant temperature sensor you have replaced it should be Green Colour and not back one.


Ash


Coolant temp sensor readings were ok roughly 90 degrees when warm only replaced as it came with the new water distributor housing. live readings still ok. Colour green.

thebigman

[thebigman]

Things to check:
1. Live data from maf
2. Live data from MAP
3. ECT sensor readings live data
4. Fuel pressure
5.Sticky injectors (check for leaks)
6. Air intake clogged (air deficit)
7. Faulty ECU
8. Air temp sensor (not much important)
9.O2 sensor live data (very important if wide band sensor used with 5 or 6 wires)

I'll have a look at the fuel pressure and o2 sensor on monday. It is a wide band sensor. Its a hanatech scanner i'm using and i'm unsure how to test the o2 sensor under vag settings. Had a look under obdII and it was reading about 2v at idle and rising to about 4v when i rev it. I was suspecting o2 sensor as the overfueling seems a lot worse on closed loop once it warms up. maf sensor is fine on live data and scince i replaced the air hose the dtc hasn't came back.

thebigman

[oldford]

Voltage on wideband sensors doesn't tell much. What's the ratio that is displayed along with the voltage?