michaelburrows

HORRIBLE PULL AWAY UPDATE on 2.0 tdci

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iv just driven through london and the temp guage got to half way point. usually car reaches the quarter way point normal driving and motorway driving. noticed that the hotter the engine got the horrible pull away totally disapeared and the car pulled away beautifully as it should. is there a reason for this.? perhaps there is a sensor that needs replacing which causes the horrible pull away.  i.e a water temp sensor or something. it was a shame switching car off because i bet when i nxt start it and temp dosnt get really hot it will return to horrible again. any ideas anyone.

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Placebo effect probably...  I never noticed mine stopping when warm, though it did get slightly better.

It sounds like you may have a faulty thermostat though, should reach half way on the gauge during normal driving unless you only do short trips?

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should it. i had a passat that used to get coolant temp sensor issues .caused all sorts of problems. wo dering if the focus has a coolant temp sensor that somehow has a effect on the pull awY issue. seems strange. but honestly. yesterday was the hottest the coolant had shown on guage. i e half way and the pull away issue totally disapeared. 

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You could unplug the coolant temp sensor to rule that out.  The engine fan will run constantly and the temp display will show -40c but the engine should run just as well.  

I still think you've got a thermostat issue though, how far are your normal journeys?

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normal journeys not really long enough to properly warm up. but travel from london to yorkshire once a month. even then temp guage sits arou d the quarter mark. occasionally rising to half way tben i assume the fan has come on or the thermostat has closed because the ttemp then goes back down to a quarter. yezterdays trip into town in stop start for 14miles the temp guage sat at half way all the time and car as i say then had no bad pullaways either.  strange but true. 

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I'd say it doesn't have a great pull away, but I've got used to it and I've compensated. If I'm not paying attention then it will drop the revs when I pull off, but normally I give it some extra right foot anyway and there's no problem.

It kind of feels like when you switch the speed limiter on - if you accelerate hard towards the limit you've set, then the engine starts to lose power just before you hit the set limit so you don't go over. So maybe it's something in the power train control to stop excessive power going to the front and causing wheel spin?

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goodness, that's an interesting point, greasy roads, cheap tyres, worn shocks and bad driving bringing in traction control?  How many owners with this (either don't have so its not this) or turned off traction to see if this helps?  These system are often agricultural and take seconds to get over themselves even when traction is back.

I was also intrigued to know how many owners with this, have hill start assist.  As one of our resident experts was saying the early ABS units have poor software that causes this issue

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iv turned traction off and it makes no difference. as i said mine got 100%better once the coolant temp was reading half instead of the usual quarter. iv had a pcm software update. made no difference at all. my engine revs freely when in neutral or clutch depressed.the only time its a pig is when pulling away in first gear. i basically have to drop clutch at no more than about 1100 revs otherwise if higher revs they drop straight back down. its a pig pulling away on gradiants. my compesatory driving is i have to drop clutch at just above tickover revs then when  its moving thigs are fine. hate the car for this reason.

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thanks for the update, why that would be engine temp dependant is intriguing,

On the temp bit I would fully expect a tractor engine to be happier when fully warned up....   how are your glow plugs?  lots of modern cars have them on off all the time the engine is running, they are no longer just for start up.  You could short the temp sensor and see if the car is normal on a cold engine?

but the description of the fault sounds more like traction control cutting in - when it shouldn't

  1. is there a switch on the throttle that's saying pedal closed when its not and thus signals confusing the engine management
  2. errors from ABS sensors or ECU putting wrong info into PCM (via traction control - but ought to go away when its turned off)
  3. bug in the software
  4. comms errors on the canbus

 

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Hi,

I also have the issue described (as people may have seen me posting about before).

However last week I had several days where the car did not behave this way and drove as I would expect.  This leads me to think there may be a metering fault somewhere, possibly the air flow meter or a similar sensor which isn't broken as such so no fault is detected by the car but influences how it behaves.

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mine also last week staryed driving as youd want it to after it had reached a hotter tempreture than b4. and iv got fingers xd its still running well.  for how long i dont know. i dont know if this is relevant.  when i used to be running car along at abuot 30 in 3rd id be feeling a sort of hesitation. i.e if i put my foot down a bit and increase revs it went  likewise if i dropped off the revs a bit it went.  si ce car has been running ok    fingers xd     no heitation either 

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Mine behaves exactly the same. It has times when it goes smooth and times when the pull of and changing into second gear is horrible (2.0 tdci 2015).

Have you figured out what's the cause ? Is it the hill assist system messing with the ECU?

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Yes had a similar issue for many many months where as the coolant temperature would sometimes reach halfway(82-84c) then drop again to 1/4 (76-77c) then sometimes stay at 1/2 all day or never get to 1/2.    When at 1/2  on the gauge the car ran smoother/quieter and the transmission shifted better as it's temp is related to the coolant more.

After many bitching sessions to ford and them in denial they finally changed the whole thermostat/housing(warranty) and instantly the engine gets up to normal(1/2) quickly and doesn't budge.

sits always between 82-84c and transmission gets up to temp around 80c too and no pinging/rattling etc and  very smooth again.

have you thought about doing a full 'reset all adaptions' with forscan  and a reset /relearn on the powershift trans just get everything to default and relearn again?  may help?

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Hi,

I have now done some further investigations on my part.  Disconnecting the MAF had no improvement or change in the behaviour.

I have since run Forscan and recorded a variety of sensor readings.

On the occasions the engine does its rev surge when pulling away, the fuel rail pressure spikes above the desired rail pressure reading and the turbo boost also increases to 90% before both suddenly drop down again.  What would trigger this to happen?

Thanks,

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Interesting find!  I can't think of anything that would cause that apart from the anti-stall tbh.  Did you also log the EGR at the same time?

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Hi

The EGR looked to behave correct, being closed under load and opening on overrun.  There was little to no variance between desired and actual position.

It may be the anti-still interfeering later than it should be but I do not know why or how to change that.  The anti-stall works if you use the clutch pedal without touching the accelerator.  The only further item I would add to my previous post is it looks to coincide when the clutch pedal position sensor is reading 25%.

Thanks,

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Hi

Having done some more digging around I have read about a SCV which controls fuel rail pressure.

If this is faulty will it give the symptoms described above?

Thanks

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If you watch the EGR opening, is it moving as you try to pull away?  This was a big issue on the 1.6, it's not a fault, it's just mapped badly.  It's slightly open at idle and then moves as you pull away which confuses the MAF sensor and the ECU can't work out just how much fuel is needed quickly enough.  It's only a split second but that feels a long time when pulling onto a fast roundabout.  

You can't change the anti stall, it's part of the mapping.  It is a bit harsh and over compensates on diesel as it really wants to avoid stalling.

The SCV (or FPR) sounds like it's working fine, the usual issue with them is running on after engine shut off (too much fuel) or cutting out under load (not enough), they don't tend to cause minor niggles like this.  The fact the boost spikes at the same time looks like it's something that's meant to happen and part of the mapping, rather than a fault.  

 

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Hi

Thanks for the reply. I haven't found the absolute position reading on Forscan, only the difference between desired and actual which stays pretty much near nill as I would expect for a working EGR.

If there is no way to easily rectify the rev surge where it revs up rapidly another 200 to 500 rpm over what I input as a driver, then I think I will be moving the car on.

Thanks,

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Hi

By a brief update, the car drove really well for part of my commute this morning. It didn't do it's revvy thing at all and behaved like any other normal car, and then it started doing it again late on in the journey.

I cannot imagine a manufacturer releasing a car that behaves like this as normal. But I don't know what can influence it when all the sensor readings are showing fine.

What also regulated the anti stall and fuel rail pressure? Can there be a dodgy solenoid or vacuum pipe that is causing the anti stall to kick in aggressively when it's not needed?

Thanks,

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