Help with 2008 Mondeo Petrol 2.0 and Forscan mode 6

[scoobydo123]

Previously was getting misfire on cylinder 2 ordered new ign coils from fords. Changed the suspect one cylinder 2 but still getting large counts of maximum emission threshold misfire rate but also despite taking it on a 15 mile drive the individual misfire data is still showing not ready. Also have an o2 voltage amplitude and voltage threshold error that seems to be pegged at 999.9mv. Dont know history of vehicle as is a new purchase from private individual. It seems to drive ok and no CEL has been displayed. Only complaint is from cold you can feel the misfire but not driven it from cold since putting the single new ign coil on. Any help much appreciated

[E-bmw]

Surely "not ready" means there isn't enough data to display yet, as in there haven't been enough/any to display.

Admittedly, I am no forscan expert.

Edited by E-bmw on Thursday 13th February 09:02

[Richard-D]

Any fault codes on generic OBD2?

[scoobydo123]

Only update I have so far is that after me changing the single ign coil that was previously reporting errors that today from cold no misfires were felt. Agree that not ready is likely part of the specific obd2 drive cycle but a bit surprised that it had not been completed. However I don't like that even at tickover the misfire count increases and of course the pegged lambda reading. Will update when I get to plug it in again and will also try generic code reader. Tks

[scoobydo123]

Here are reports via my Autel dongle. Seems like still there are minor misfires but passable and still some incomplete monitors. So maybe the o2 sensor is causing the issue as they is out of range so maybe the cause of the incompletes. Car will be used again tomorrow so will run another report.

Edited by scoobydo123 on Thursday 13th February 22:24

[Belle427]

So to summarize the pre cat O2 sensor is pegged rich with no codes logged and there is a misfire?
Cat not partially blocked is it?

[scoobydo123]

Hi when driving the o2 sensor cycles between lean and rich. It is in mode 6 that it is pegged outside the normal range TID 80 There is also a misfire in the 50,000 TID 83. But not many on the individual cylinder monitoring.

Edited by scoobydo123 on Saturday 15th February 07:51

[scoobydo123]

Emission threshold misfire rate now at zero since changing all ign coils. However my Son for some unknown reason runs the car with only 50mile range on a regular basis so maybe the misfire monitor is not active when low on fuel as I have read something about that. Have had both o2 sensors out and tested on the bench heating with map gas and when glowing red they output 0.96v and quickly taper off when the flame is removed. However I was surprised that if I took the heat off and just had gas flowing into it it did not read rich. Whilst o2 sensors were off I put ta camera down the o2 1 sensor and it looked very clean inside not sure if thet is normal. Remember at one stage someone had been at this in the past as it had an odd ign coil in. Also the emission report done a month before the mot it only just passed the natural idle test on HC which was 3 points within the max. But car has been serviced by the seller after this. Here is a video inside the cat.

https://drive.google.com/file/d/10qgN1-7sVZijEtPel...

[scoobydo123]

Richard-D said:

Any fault codes on generic OBD2?

Hi sorry for the delay nothing on a generic code reader ie. No p codes. Interesting it didn't lodge a p1000 after codes cleared which I would have thought should have been sitting in there. Tks for the interest.

[scoobydo123]

The voltage amplitude has gone down by 250mv since driving it around but still is showing up as out of range on Mode6. Misfires just getting 0.25% on cylinder 3. I cleared the code and moved the sparkplug to cylinder 4 and the misfire followed :-) Put a new sparkplug in cylinder 4 and done 9 miles after clearing data and now have a misfire on cylinder 1 which I have not touched. Maybe a certain amount of misfires are acceptable in mode 6 data? Wanted to make sure that the voltage amplitude is not a symptom of causing the misfire data. Got a new o2 sensor on order but the old one looked fine when looking at the sensor data ie was cycling low to high rapidly during closed loop. Feel like not getting anywhere with this.

[scoobydo123]

Ok update time and comments most welcome. So all monitors are completed after taking it for a run at 70mph and letting it coast down to less the 40mph a few times. During this test drive I got the 2 misfires back on CYL 1&2 logged as a value of 0.25%. There are now no misfires logged in the section that was previously showing 50,000. car has had a tank of Tesco 99 Ron and seafoam injection cleaner put in. The the intermotor o2 sensor came today and I have fitted that (pre cat) post cat is factory still. At idle the pre cat cycles rich to lean quickly and the post cat sits around 0.7v.

After fitting the new o2 sensor I took the car for an Emission test previously before I purchased the vehicle in Jan the last MOT in November had the below readings

Fast idle CO 0.000% HC 0ppm Lambda 1.003
Natural Idle CO 0.297 (so just scrapped in)

Now
Fast idle CO 0.00% HC 5ppm Lamda 1.00
Natural Idle CO 0.00%

So still have the o2 sensor voltage amplitude reading 0.7338 scanner says MIn should be 0.5000 and Max 0.0000 which seems backwards but anyone is out of range and misfires on cylinder 1&2 reading 0.249%.

Attached is the switching of the o2 sensor at idle.

[E-bmw]

Pre-cat controls the engine management, post cat is just for monitoring, so that looks fine.

[scoobydo123]

OK thanks just got the niggle of the misfires being reported in mode6 and the o2 sensor 1 amplitude and threshold showing out of range. It has shown a trend in the right direction from 999mv to 733mv.