Discussion in 'Technical' started by VahanPujari, May 15, 2010.
At 40 km/h, you should change to 4th gear, otherwise any car in 5th gear at 40 speed might stall.
You are lugging the engine. Shift down
Multijet/DDiS engines are equipped with Anti-Stall feature. When engine reaches to stalling situation, ECU injects small amount of fuel to prevent engine stalling.
Take a small test.
1) Let the car roll on at 25km/hr in 3rd gear for some time on incline.
2) Reduce the speed upto 20 km/hr touching the brake softly
3) Then press the clutch without touching accelerator & brake paddle.
4) While pressing the clutch ,observe the Tachometer needle.
If techo needle jumps for a little bit,then your anti-stall feauture & stabilsation function of battery charging current
is working fine.
If not then go TATA ASS & scan the ECU.
Engine will not stall. ECU is programmed to run with nil accelerator. Min speed for each gear is specified in this case. For 5th gear it is 35kmph. I did this once on an empty stretch of about three km. Put the car in 5th gear and took my foot off accelerator. It was an amazing experience.
As per Fiat, moment you take your foot off accelerator, engine operates in fuel cut off mode, but ECU keeps injecting little amounts of fuel to maintain momentum at min speed for each gear. Try it out.
Edit: I posted above without reading Sudhakar's post. In case of brake application and maintaining in gear with foot off accelerator, engine will stall as free momentum is not available.
Amol bhai, nice information,
I will try sometime on free road.
Yes, my Petrol Punto runs on 20kmph on 5th Gear and doesnt stall...anything lower than this speed it would...but on a straight flat stretch, it goes on without shuddering...
Plus in my pervious Verna Diesel, it worked the same way.. my office parking in lower basement (-2) and someone has put in (illlogical) humps on the climb part of the ramp...to avoid stalling and easy manuveouring on the corners, i used to leave the car on 1st gear and let it do the climbing (without pressing the acclerator)... fuel used to flow to compensate the require speed of 10 KMPH.... and never did the car stall...
Simply put ECU does make small amount of fuel to flow and run the car on its own...Robotised !! ::T
BHAI....you are the anit-stall here when you press the clutch. There is no such thing AFAIK , just that at stall speeds ECU sends in more fuel. Engine cannot stall when you press the clutch.
When you press the clutch....engine jumps back to idle engine speed as you must have been running lower than that when on an incline in 3rd gear.
Rightly said Kaps.....that is just amazing. you can actually reach 5th gear without touching the clutch. I have tried till 4th though.
I agree that engine can't stall as we press the clutch. But there is small time gap between starting of release of clutch & fully release of clutch. In that time gap,there is possibility of engine stalling. So this feature is given.
See inside of dashboard.& see the Clutch paddle. On clutch paddle you will see the switch like brake light switch.
When you press the clutch, this switch sends the signal to ECU,that you are going to release the clutch. That's why at that time RPM needle makes little bit jump.
& this feaure is also used to stabilise the charging current of car's battery.
See the owner's manual. FIAT has mentioned that some time RPM needle jump. This is normal function.
This jumping is given to stabilse the battery chrging current at low RPM .
K...Will try for sure. Thanks for that info.
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