termin8r Posted December 19, 2012 Share Posted December 19, 2012 Hello everyone. I'm new to ford ownership. Bought a pre-reg with 0 miles smax in October. It is 2.0 TDCI zetec. Already had the window motors replaced on the front. Bad start.. Next issue seems to be the non-linear reponse from the accelerator which causes difficulty in taking off from stopped. If i press the accelerator slowly whilst in neutral , there is no reponse from the engine. At a certain point it then jumps straight to around 2000rpm or higher. Why is this? My friend you co-incidently bought the same car seems to have the same problem although i have not tested their car. ECU anomaly? It certainly makes the car hard to drive without either conking out or revving it excessively, Any ideas? Sam. Quote Link to comment Share on other sites More sharing options...
FOCA Posted December 19, 2012 Share Posted December 19, 2012 There may be a number of reasons for this - 1 - The throttle is a potentiometer (variable resistor) it sends an analog signal to the ECU - (like a mouse on a computer) it is not connected directly to a carb or thottle bodies like in the "old days" it is far more complicated than that - the symptoms you are experiencing may have nothing to do with the throttle itself (as you have suggested) 2 turbo lag, these engines can suffer from turbo lag, where the turbo takes time to boost up, it can be worst off the line/ in the lower gears 3 power band - the engine may have a "power band" where the power & torque is in a relatively narrow band - for example the engine may be "gutless" below 2k, then there is a sudden rush of power, then the power drops off above 3.5k - some engines are like this - the mondeo TDDI was like that, and the PSA Mondeo 162 is like that - a remap, bluefin or tuning box can help this 4 - there is a microswitch on the clutch pedal - this sends a signal to the ECU to "!Removed!"/ restrict the engine, this stops you from revving the engine when the clutch pedal is down, "slipping" the clutch "racer" style, by reducing the power/ torque during a change (all this protects the DMF/ clutch and is supposed to smooth out the gear change ) - i have disconnected this switch on my car and it makes a big difference, gearchanges are sharper, engine picks up better etc (i return it back to normal for snow etc) 5 the Maps/ setup of the engine may be biased towards emmisions/ economy throttle response/ drivability may be a low priority in the way the car is set up - again, a remap/ tuning box would help here, or perhaps an update on the manufacturers map 6 - all this stuff may be (is) interconnected, it could also be connected to the EGR and DPF 7 - anti stall - ECU is boosting the revs to prevent stalling? and otherwise reducing revs for better emmisions/ economy you probably have the PSA engine, a joint venture including Peugeot amd Citroen Quote Link to comment Share on other sites More sharing options...
termin8r Posted December 19, 2012 Author Share Posted December 19, 2012 Thanks for your response. I also have another car which is petrol and "fly by wire" accelerator also. It idles around 7-800rpm. When i (in neutral) press the accelerator extremely gently the revs rise slowly as expected and it is a very linear and smooth response. In the SMAX it idles around the same but pressing the accelerator in the same manner results in no increase in engine revs until a certain point where it just snaps to 2000rpm or above. This symptom would indicate point 1 or 5 above. It is not turbo lag or clutch related as I am in neutral and the car is not moving. I ran the ford garage and they told me to ring the technical number. But at £1 per minute, why should i have to do that on a new car?? Just wondering if anyone else has an 2012 smax and whether it does the same thing. Quote Link to comment Share on other sites More sharing options...
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