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Personally I'd disconnect the battery positive lead for 30 seconds or so then reconnect and start the car and let the ecu re learn the idle again and see what happens.

Ciao
 
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Personally I'd disconnect the battery positive lead for 30 seconds or so then reconnect and start the car and let the ecu re learn the idle again and see what happens.

Ciao
Good suggestion. After my HG fix, she wouldn’t idle. The shop said they had to teach her how to be an RS again. My mind won’t let me imagine what that lesson was like.
 

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2017, Mk3 Focus RS. Stock, for now!
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Discussion Starter · #43 ·
Plot twist!

Plugged into IDS, there are signs the crank case pressure sensor is faulty!

Replacement coming tomorrow - will advise if this fixes it!
 

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I really wish that Ford would let the vehicle owners have an IDS license. It seems that there are lots of diagnostics through that that are not available to standard OBD dataloggers. In addition to what you found, I think per cylinder misfires would also be handy to see.
 

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Discussion Starter · #45 ·
I really wish that Ford would let the vehicle owners have an IDS license. It seems that there are lots of diagnostics through that that are not available to standard OBD dataloggers. In addition to what you found, I think per cylinder misfires would also be handy to see.
For sure. You can get IDS in the UK as a DIY/end user, but the subscription is £3k plus the equipment annoyingly.

Strange thing is I had no engine management light on etc. And when it was plugged into IDS previously 2 weeks ago, no such faults were found. But the low idle issue complemented by the new high 1500 idle must have set something off I guess.

I'm a bit sceptical this is going to fix my issue - but I guess I'll find out tomorrow!
 

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Discussion Starter · #46 ·
Took it to Ford today. My issue is intermittent, but thankfully it done it in front of Ford today. No DTC's, and they couldn't find anything obvious in the live data versus reference values. So they data logged and sent to Ford technical. Ford technical should come back in a few days. I'll let you all know what happens. Good experience with Ford there to be honest. Couldn't have been happier with how that went.

Hopefully we get a resolution, as it seems I'm not the only one here with the issue!
 

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Discussion Starter · #47 ·
Sadly, no joy. Ford technical not sure what's wrong (garage wouldn't tell me if issue was present during the datalogs they sent right enough). So not really got any idea how to proceed from here sadly :(

Tried replacing throttle body too, but no joy.

Only thing I can think of is try to get a ride with one of the ford techs, as I know how to bring on the issue pretty easily, and make sure they're datalogging when it happens. Will phone them Monday to see if they'll entertain that.



Foot note - issue seems especially bad just after filling up from empty to full. I've replaced the purge valve already. Anything else fuel side that could cause this? Perhaps my flap isn't sealing correctly?
 

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Discussion Starter · #48 ·
Update. Went to Ford today and managed to get one of their guys with IDS for half an hour. Got some solid data logging done. It done the rev surge, the high idle, and the leapfrogging during data log. Hopefully something will pick up the issue. Just waiting in Ford technical coming back now. Update in 3-4 days, hopefully!
 

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Discussion Starter · #49 ·
Update - apologies for delay. Sadly the data logs looked great, even to ford technical. You could see the desired RPM was 700/800 but of course there was the dips to 550 and the 1500 idle shown on the actual RPM.

Unfortunately, none of the logged values indicate why the idle is differing. It was the 700/800 zone, but it's often getting 1500 idle, or if it does idle at 700/800, there's the occasional double pulse down to 550 if the A/C is on.

To this end, I am wondering if the issue is mechanical rather than electrical. Could it be possible I have a alternator or A/C pump that is starting to seize? Prior to me getting the car, it had only 8k miles on it over 2 years, so it probably had a good bit of no run time.

I also notice that if I'm idling with everything turned off, then I engage the heated windscreen, the idle starts to unsteady. Then if I engage heated seats and rear windscreen, it is more unsteady. If I then turn on the A/C, it goes proper hunting idle. So 650-900 revs back and forward back and forward. Could this indeed be the sign that something is slightly seized/on its way to seize? I have no issues at higher rpm whilst driving - assuming the power at higher rpm can deal with the slight seizure? Would this make sense to anyone?

I might point ford in this direction next time I'm in.
 

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Discussion Starter · #51 ·
Further update - turns our ford technical couldn't actually open the datalogs we sent them (corrupted or something). Twice this has happened so far, not sure why it's happening
 

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Discussion Starter · #52 ·
I wonder if it could be the solenoid in the vapor canister.

Code P2450- Evap Emissions Valve

Otherwise the other hardware could be fuel filter or dirty fuel injectors.
Replaced fuel filter, no change. Will suggest vapor canister itself/injectors. I'm a strong believer it could be something to do with the vapour cannister though... Seems to be worse when the tank is low and a lot of sloshing of fuel has happened
 

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Discussion Starter · #53 ·
Further update. Finally got a datalog that Ford technical could read. HPFP pressure readings within parameter range but a bit a bit low. Suspect some kind of leak internal to it. Slight smell of petrol around the area of it. Ford recommending new HPFP. Getting this done on the 12th. Fingers crossed that solves the issue.
 

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Further update. Finally got a datalog that Ford technical could read. HPFP pressure readings within parameter range but a bit a bit low. Suspect some kind of leak internal to it. Slight smell of petrol around the area of it. Ford recommending new HPFP. Getting this done on the 12th. Fingers crossed that solves the issue.
Did it work?
 

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@Jgray2016 What a saga, dude. Your persistence is legendary.
 
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Discussion Starter · #58 ·
So no joy on last datalog, however this did happen:

Booked in Tuesday for proper diagnostic. But went tonight and I didn't catch the actual fault code but apparently it indicates harsh combustion. Will see soon enough next week...

Odometer Speedometer Trip computer Car Tachometer
 

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Discussion Starter · #60 ·
Diagnostic reveals...P0327

Diagnostic points to both NoX sensors having faults. Booked in for replacements now.

quick Google says nox sensors can apparently cause crummy idle..... So hopefully this is the source of my issue at last. Will soon see!
 
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