Focus ST hesitation issue

[collyirwin11]

Well people, looking a bit of advice about my focus.
Jumped into the car on saturday and it just didnt feel like it was running right, it drove ok, but just something felt wrong. Then on sunday it developed a slight hesitation as I was driving along. This progressively got worse until yesterday when the juddering and hesitation became very erratic and constant. Since then the boost gauge now has a merry dance all by itself. I must add that this all takes place at a constant cruising speed. The car will still pull ok accelerating and the boost gauge works ok when spooling up etc. I originally thought air flow meter so yesterday I got some cleaner and cleaned it out, and also replaced the spark plugs, the 1s which came out are not too bad but could have done with a change. Anyway, no difference was made and the car is still lumpy and juddering. I took it a run there and recorded the boost guage mucking around. I have drawn it down to what I think the 4 possible areas at fault could be
MAF or MAP sensor
Boost solenoid valve (however it does still boost ok and when accelerating it is still driving ok)
Coil pack
But would like any advice others may have or anyone who has experienced similar issues. I must also add that there is no evident boost leaks and the car has no warning lights or errors coming up on the dash.

Here is a video of what the boost gauge is doing at 30mph

 

[Nigelo]

I'm going to go for a dead maf sensor, although I'd have thought a code would appear. Its the only thing mentioned that could, in my novice brain, connect shuddering (fueling issues) with boost gauge wobbles. Either that or a dead 02 sensor causing fueling issues. Particularly if the issues only occur when the car is in open loop, as opposed to closed loop. (Or it that the other way round.)

 

[Nigelo]

Meant to say as well, I have the ford elm cable if there's any pending codes, or diagnosticy stuff.

 

[collyirwin11]

Meant to say as well, I have the ford elm cable if there's any pending codes, or diagnosticy stuff.

Ill maybe get you to plug it in if thats ok.

I have a million different reasons going on in my head about possible problems, including throttle sensor as well. Its all just very odd. Took my brother out in it and it wouldnt jutter in the same manner as it had with me, I explained the symptoms about how it just feels very laggy at a constant speed (not boost laggy just throttle laggy) and so he drove it and was able to see where I was coming from, that it just gets this hesitation (almost like you applied the brakes). The car will still drive 100% when accelerating, and it still holds boost pressure, it just seems this hesitation occurs at a constant speed.

 

[Nigelo]

I'm out tonight, but I'd be available tomorrow evening. Hopefully it'll either go away or at last give you an obvious code.

 

[collyirwin11]

No problem. Thanks. Ill not be able to make tomorrow night, but maybe saturday morning/early afternoon if your available.

Thats what I am hoping, as if it threw up an error code at least I would know where I am and what I could replace. I have even thought it could have been dirty fuel as I last filled up in carrowdore with super (always run it on super) and lord knows when they last got a refill so could just be that.

 

[Wild Thing]

Sounds like a maf and they generally dont throw diagnostic codes. If its gone cleaning it will make no difference, see can you beg borrow or steal one to try, as motorfactors will not refund them if the seal is broken on box or bag

 

[collyirwin11]

Today we have had really rough running, the idle was erratic, bouncing from 500rpm upto 2000rpm when I first switched the car on and then on an occasion where I had stopped at a junction. When driving along there was constant jerky and hesitating unless building speed and this time the boost gauge was generally bonkers the whole time. Usual mpg figures have dropped dramatically as well.

 

[mthompo]

Today we have had really rough running, the idle was erratic, bouncing from 500rpm upto 2000rpm when I first switched the car on and then on an occasion where I had stopped at a junction. When driving along there was constant jerky and hesitating unless building speed and this time the boost gauge was generally bonkers the whole time. Usual mpg figures have dropped dramatically as well.

You have pm chum

 

[brocks]

Not sure if its the same on the ST as the RS, but pulling fuse 26 which is the KAM fuse can clear all manner of gremlins...though do NOT do it until you have had the car checked with a fault code reader as it removes all stored codes...........it then takes the car a while to relearn the new fuel trims etc..

Could also be a faulty boost solenoid which I believe is a common problem on these.....solenoid will not throw an error code, if you read the text on Jamsports sales page some of the symptoms are similar FYI
http://jam-sport.co.uk/shop/mk2-focus-rs-and-st-225-boost-control-solenoid/

 

[collyirwin11]

Yes, pulling out that fuse does the trick with the eng management light (because of the decat). I am currently swaying away from boost solenoid (only slightly) as it does boost ok and it does hold boost, whereas this seems to be at cruising speeds when I am not using the turbo. I am beginning to convince myself it could be maf sensor, but i keep thinking it could also be coilpack, or even a dodgy fuel sender. But then I think that (in my limited knowledge) the boost gauge wouldnt be acting so odd with those issues, would it??

 

[gsmith]

Get it plugged in as soon as you can mate if your stuck give me a bell and il get are snap on plugged into it. Might be worth giving trust ford a bell they may know of an issue on them. All being well it's a simple fix. If you need anything let me know.

 

[mk2driver]

Is the boost gauge mechanical or does it read digitally from the ECU? If its from the ECU, i.e. it doesn't have a vacuum hose attached to the back of it then its getting its reading from the MAP sensor. If the MAP sensor is faulty then your fuelling etc will be all over the place and could cause the issues you are describing.

 

[collyirwin11]

Its connected through the map sensor to my knowledge, that is one of my options. Didnt think it would have caused such issues but thanks for the advice, would probably lean more towards it being the culprit. Hopefully get a diagnosis tonight or tmorrow with the help off @mthompo

 

[Nigelo]

If you need me for my elm cable give me a shout!

 

[mk2driver]

MAP and MAF are both measuring air input into the engine, in a different way but thats what they are doing so both can have a similar affect on the car. Its strange that it isn't flagging a code but that can happen.

 

[collyirwin11]

Got a lend of a diagnostic and took it a run. It brought up codes p0236 and p0238 (photo below). To me these codes would imply boost solenoid, but the car still holds boost. I took @mthompo a run, and it only slighted highlighted the issue with him in the car. The way it drives would imply maf with its hesitation, but then the boost gauge would imply map sensor and it just dances around when there is no boost being built/used.

 

[Nigelo]

What about that last one - maybe O2 sensor on the way out?

Or is that just the decat?

 

[collyirwin11]

That code always appears because of the decat, I have a lambda spacer on the 02 sensor because of this and it would throw up eng management light every couple of months with that code. It would usually not mean anything, but do you think it could be related?

 

[Nigelo]

Nah, it's definitely the decat, forgot about that!

 

[collyirwin11]

Found this website referring to one of the sensors listed above.

http://www.powerstrokenation.com/forums/showthread.php?t=17128

So tomorrow I may just buy a MAP sensor and go from there.

 

[collyirwin11]

Bought a replacement MAP sensor, fitted it and took it a run, so far it seems all is well again.

Thanks again for all the help fella's, thanks to @Nigelo for offering his services and an extra special thanks to @mthompo who leant me his diagnostic kit.

 

[Nod]

HI Guys I'm hoping you can help me I have a focus st 2007, last weekend the had a system fault but when I ran a check no codes, but I'm only boosting to the first mark on the boost gauge, I have changed the boost solenoid valve but still no change, I disconnected the MAF and ran the car but got ESP fault, can you please help !!! running stage 1 bluefin and cat back are the only mods

 

[collyirwin11]

Disconnecting the MAF will cause it to bring the ESP light on, I had a similar issue with it more recently and I had a hole in the intercooler. My hesitation issues was linked to my MAP sensor. The boost issues could be a leak, so check all hoses and then if nothing visible, possibly book a smoke test. Failing that @mk2driver helps a lot