Annoying Misfire I can’t find or fix

[71-bda]

have you checked all the air hoses ?

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No nothing.

No Mods. No rockers. Just a chunky knob, thats now been replaced by an RS knob innit.

No tackiness.

Std as Ford intended, but with a space saver wheel and jack and nuts and wheel brace. oh.. and flaps, a man has got to have flaps.

Innit?

 

[Lucky_]

Do a smoke test to check for any leaks.. Only costs about £25.

[kozyoncars]

I’ve checked them visually and all connections. Everything looks ok. No visible cracks. Kinks. Pulls etc. everything is connected as and how it should be….But it hasn’t been smoke tested. The garage were reluctant.

I’ve just done the vac pump and replaced all the coils and plugs for OEM. The major lumpy issue caught on video is 90% improved. But the car did surge a couple of times and feel hesitant/under powered.

Got it back home. Checked over it again and this time the code reader caught p0171. Which wasn’t present before and now is.

The car does run better but still idles rough after you give it throttle.

I’m led to believe it could be evap or fuel pressure. I do have the FPS on order so should be here tomorrow. I’ll do that next. I could order the evap as well but it will take a while as not in stock.

That’s it then. That’s every sensor engine side replaced. Regardless of the cost and reluctance from garages to hunt the issue down, it will have to go in somewhere to get sorted.  I’ve exhausted everything I can do on the drive ….. Except compression test 😬

[Lucky_]

P0171

https://www.focusrs.org/threads/p0171-and-p2195-bank-1-lean-sensor-signal-biased-stuck-lean.112086/page-2

[JohnD]

As an aside. On the point of the blanking plate. I’ve had turbo cars with big power and associated intercooler upgrades from Impreza to RS’s of several brands. I’ve never heard of condensation on an intercooler being an issue. I mean on certain Subaru cars I’ve had. They had IC water spray as standard… So essentially the same effect I would imagine. What makes the Ford different or is that a can of worms I should just leave alone?

 

Just as an aside, the IC water spray on the Subaru was on the outside to cool the IC.  The condensation issue with the RS IC was on the inside

One thing you might try. (unless I’ve missed it) is an alternative map?  Revert to OEM or load a different map or maybe re-flash the M375.

 

JohnD

[kozyoncars]

@lucky – I’ve been reading that thread.

Got the sensor coming tomorrow so I’ll get it changed.

Wonder if that’s been a contributing factor all along and only now thrown a code.

 

@johnd interesting. On vs In. I would imagine condensation inside the cooler would also cool the air but also dry off before being of any great volume enough to cause hydrolock.

I also don’t see how the plate stops it? As the water wouldn’t collect anywhere but the top, bottom or sides in my mind. Covering a certain percentage surface area of the cooling  vanes, would do little – in my mind, to stop that happening.  I’m not questioning you btw just trying to understand the problem. If I go after market they wouldn’t be blanked and I’d assume the same problem would exist. Or is it specifically the flawed design of Ford’s intercooler? Makes me want a bigger better after market one if that’s the case. Lol

You guys are being super helpful. I really appreciate it. Thanks.

[71-bda]

the blanking plate was used to have the effect of reducing the surface are of the intercooler, as basically it was a bit too efficient/over sized for the engine in certain conditions of high humidity and low ambient temps. moisture was forming in the intercooler and would now and thn get sucked (blown) into a few cylinders causing a shorting of the spark plugs and a moments misfiring. It was not put on for fun. Frenk in Switzerland had the issue and cured it by putting the plate back on. The issue would show up after a long medium high speed constant cruise when more power was asked for. So// up to 375bhp in the uk, blanking plate on, over 375, take it off ! (Maybe put it back on in the winter!)

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No nothing.

No Mods. No rockers. Just a chunky knob, thats now been replaced by an RS knob innit.

No tackiness.

Std as Ford intended, but with a space saver wheel and jack and nuts and wheel brace. oh.. and flaps, a man has got to have flaps.

Innit?

 

[kozyoncars]

@71-bda it’s interesting for sure.

My blanking plate simply disintegrated. Seemed to be made up of some sort of cardboard/plastic and it just became brittle.

I guess it’s something else to fix eventually before winter…I say before winter but not like we get much of a summer lol that said I think I’m going to move the car on, once this is all fixed.  Been one thing after the other since purchasing. I’m only really determined to fix this misfire/poor running in order to put it on the market so the next buyer has a better experience than I’ve had 🙁

 

 

[kozyoncars]

This car…. (Polite) Words Fail me!!

I’ve got the new fuel pressure sensor in and the car and the code for fuel pressure disappeared. But the car is now running worse than ever. The sensor is fine as tested it. The issue has jumped by the looks of it back to either the front O2 sensor which was already replaced about 6 weeks ago – code says stuck open running rich.

I started playing with stuff and unplugged the HPFP and the car started running about 90% better. Not perfect. But it certainly looks as though that is an issue now but no codes about fuelling.

It just s seems to be cascading issue failing over to one area after another.

[kozyoncars]

Well, thank you everyone for your help.

Eventually spent a full day working on the car. In the end, swapped out Vac Pump, Vac Boost Servo Line and HPFP.

The misfire is cured and the car runs great.

Asides a new issue. I’ll post separately about it.

Anyway, car will be for sale soon if anyone is interested.

Thanks

[Author]

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