Smooth gear shifting

[Garrison]

Yes I do believe it's a ford engine in there.

It seems to be that no matter where I let the revs drop to from between 1st and 2nd I get a jerk. I don't believe there is any clutch issues my car (I have a good mechanic I trust and get it serviced regularly).

The only time I don't get a jerk between those 2 low gears is if I literally only Rev it in 1st to around 1400rpm and then let it drop to 1000 before letting the clutch up, which is clearly no goof when wanting some good firm acceleration without holding up traffic behind, or when want to pull away on a hill!

From your descriptions, that is the typical behaviour of the TDCi engine.

Firstly, there is an aggressive anti-stall below 1,250 rpm, unless the clutch pedal switch detected your clutch is out. When you change gear, you may have inadvertently trigger the anti-stall some of the time but not the other depending on your clutch pedal position, throttle position and engine revs combination.

Secondly, you clutch pedal switch may be faulty (or intermittently faulty) as mine was in my car (fixed under warranty).

Thirdly, you are on turbo might be on boost or still building boost pressure in first as your change into second, which will be off-boost), making the transition even more difficult to control.

I have two workarounds without taken a very, very relaxed change or double-declutch

1) I did what you said to change out of 1st before the turbo comes on boost at below 1,600 rpm and catch the throttle in time so it does not activate the anti-stall as you lift the clutch in second.

2) I would stay in 1st for longer to 2,500 rpm and do a sustained throttle change so I stay on the turbo when I lift the clutch in second at over 1,700 rpm.

I felt the anti-stall activation is based on the engine revs and the clutch position sensor rather than the throttle. As a result, the actual throttle behaviour will not feel correlated to the throttle pedal position, hence sometimes you can more and sometimes less than you think you need on the throttle. This inconsistency will result in the jerkiness your described as you try to predict what the engine management system may do, rather than reacting to what the ECU has already done.

Hope this make sense.

[TheInsanity1234]

My work vehicle is a Fiesta van with the TDCi engine. If I lift my foot abruptly off the throttle when shifting from 1st to 2nd the engine revs are sustained briefly which makes a smooth change hard to achieve. If I close the throttle gently the revs drop and a smooth change is possible. An annoying trait that I think is some sort of anti-stall system.

It's not anything to do with anti-stalls, it's everything to do with emissions.

Apparently, if you close the throttle quickly, it increases the amount of Nitrogen Oxides coming out of the tailpipe.

So the manufacturer's solution is to limit the rate the throttle can close. This won't affect normal everyday driving, however, if you do what you described, you get the sustained revs thing, which is called "rev hang".

The way around it is basically to not change gear so quickly

[waremark]

What are you driving? I don't know that I've ever been in anything where the revs drop so slowly when declutched that upshifts are cumbersome...

You should try my car then

I'd like to!

[waremark]

Practice the 1st to 2nd change where conditions are suitable to allow you to look at the rev counter. First, work out what revs you need in 2nd gear to avoid the engine bogging down below the turbo boost range - perhaps 2k rpm - and what speed that represents. Then find out what revs that speed requires in 1st. Now, accelerate in 1st to slightly higher revs than that to allow for the road speed drop during the gear change. During the change, don't take your right foot right off the accelerator. Lift your accelerator foot only far enough to let the revs fall to the level you need in 2nd before letting the clutch out. As you let the clutch out, cushion the movement over the biting point slightly. If this works for you, try to practice until the rate and amount of foot movement becomes instinctive. To help you get the timing and foot movement correct, listen to the engine and try to notice the movement of the rev counter out of peripheral vision.

Tell us what helps.

[Mr Cholmondeley-Warner]

Most people who have trouble with the change from 1st to 2nd are trying to do it too quickly, because of the huge gap between 1st and 2nd. You even mention this yourself - saying you "lose too much momentum" if you make the change slowly. Actually, I think you'll find you don't - you can either have a smooth change, or a hamfisted one. The hamfisted one may feel quicker, but there'll be very little difference in practice. Don't worry too much about "progress". It isn't really a feature of 1st gear anyway except at traffic lights grands prix.

[Mr Cholmondeley-Warner]

... its not something I'm immune from as Mr C-W can attest ...

I thought it was the car's fault!

[jcochrane]

As others have said a leisurely gear change can make a world of difference.
Thinking of first as only a gear to get the car rolling (not accelerating) and 2nd gear is the one for accelerating in should help as well. Using 1st to accelerate firmly away from a standstill will always make the shift to 2nd a challenge and best avoided if you are looking for smooth gear changes.

[true blue]

As others have said a leisurely gear change can make a world of difference.
Thinking of first as only a gear to get the car rolling (not accelerating) and 2nd gear is the one for accelerating in should help as well. Using 1st to accelerate firmly away from a standstill will always make the shift to 2nd a challenge and best avoided if you are looking for smooth gear changes.

What about 1st to 4th?

Not a change I use often, but driving home in a new toy I couldn't resist finding out how briskly I could get away from standstill with a clear road ahead. (Reasonably briskly, it turns out). But a leisurely change into 4th at some 35mph or so was as smooth as any of my other changes. It's a normally aspirated engine, and revs drop away easily enough without turbo-related weirdness.

I understand that a short change up to 2nd may be best for smoothness without sacrificing too much progress in the OP's car, but I'm not convinced it's universal advice...

[jcochrane]

As others have said a leisurely gear change can make a world of difference.
Thinking of first as only a gear to get the car rolling (not accelerating) and 2nd gear is the one for accelerating in should help as well. Using 1st to accelerate firmly away from a standstill will always make the shift to 2nd a challenge and best avoided if you are looking for smooth gear changes.

What about 1st to 4th?

Not a change I use often, but driving home in a new toy I couldn't resist finding out how briskly I could get away from standstill with a clear road ahead. (Reasonably briskly, it turns out). But a leisurely change into 4th at some 35mph or so was as smooth as any of my other changes. It's a normally aspirated engine, and revs drop away easily enough without turbo-related weirdness.

I that a short change up to 2nd may be best for smoothness without sacrificing too much progress in the OP's car, but I'm not convinced it's universal advice...

My post was in response to the original problem posed by the OP. Why should you be convinced that it is "universal advice" ?

Your comments of changing from 1st to 4th whilst possible to be done smoothly I do not believe that accelerating in first up to some 6/8k rpm (up and into the red) and then changing into 4th with rpm then dropping to around 1.5k is going to be very helpful to the OP. If any one were to drive a car of mine like that they would only do it once as I would never let them drive one of my cars again.

[TripleS]

Most people who have trouble with the change from 1st to 2nd are trying to do it too quickly, because of the huge gap between 1st and 2nd. You even mention this yourself - saying you "lose too much momentum" if you make the change slowly. Actually, I think you'll find you don't - you can either have a smooth change, or a hamfisted one. The hamfisted one may feel quicker, but there'll be very little difference in practice. Don't worry too much about "progress". It isn't really a feature of 1st gear anyway except at traffic lights grands prix.

For the change from 1st to 2nd, I've recently(1) taken to doing it very early, such that after I've selected 2nd gear the road speed is such that the corresponding engine speed is only a little above idling, which means I can come off the clutch pedal quite quickly and simultaneously apply a fair mount of throttle. This seems to work quite nicely for normal purposes, but of course it's not suitable if you want strong accleration.

(1) Just to illustrate that my experimenting and learning processes haven't entirely stopped.

Best wishes all,
Dave - 57 years driving, and still so much to learn...

[TripleS]

As others have said a leisurely gear change can make a world of difference.
Thinking of first as only a gear to get the car rolling (not accelerating) and 2nd gear is the one for accelerating in should help as well. Using 1st to accelerate firmly away from a standstill will always make the shift to 2nd a challenge and best avoided if you are looking for smooth gear changes.

What about 1st to 4th?

Not a change I use often, but driving home in a new toy I couldn't resist finding out how briskly I could get away from standstill with a clear road ahead. (Reasonably briskly, it turns out). But a leisurely change into 4th at some 35mph or so was as smooth as any of my other changes. It's a normally aspirated engine, and revs drop away easily enough without turbo-related weirdness.

I understand that a short change up to 2nd may be best for smoothness without sacrificing too much progress in the OP's car, but I'm not convinced it's universal advice...

Back in my 3.8 Jaguar days (late 1960s) I used to occasionally change directly from 1st to 4th. In that car the change could be made at 20-25 mph and the car would immediately pull strongly in 4th gear, before engaging the overdrive at 40-45 mph.

I'm sure many modern cars would put that in the shade, but it was a very impressive performer in that era.

[jcochrane]

Your comments of changing from 1st to 4th whilst possible to be done smoothly I do not believe that accelerating in first up to some 6/8k rpm (up and into the red) and then changing into 4th with rpm then dropping to around 1.5k is going to be very helpful to the OP. If any one were to drive a car of mine like that they would only do it once as I would never let them drive one of my cars again.

Not least because you drive a diesel and it can't rev beyond 4.5k in the first place

I'm devastated, I so wanted to try it out.

[true blue]

As others have said a leisurely gear change can make a world of difference.
Thinking of first as only a gear to get the car rolling (not accelerating) and 2nd gear is the one for accelerating in should help as well. Using 1st to accelerate firmly away from a standstill will always make the shift to 2nd a challenge and best avoided if you are looking for smooth gear changes.

What about 1st to 4th?

Not a change I use often, but driving home in a new toy I couldn't resist finding out how briskly I could get away from standstill with a clear road ahead. (Reasonably briskly, it turns out). But a leisurely change into 4th at some 35mph or so was as smooth as any of my other changes. It's a normally aspirated engine, and revs drop away easily enough without turbo-related weirdness.

I that a short change up to 2nd may be best for smoothness without sacrificing too much progress in the OP's car, but I'm not convinced it's universal advice...

My post was in response to the original problem posed by the OP. Why should you be convinced that it is "universal advice" ?

Your comments of changing from 1st to 4th whilst possible to be done smoothly I do not believe that accelerating in first up to some 6/8k rpm (up and into the red) and then changing into 4th with rpm then dropping to around 1.5k is going to be very helpful to the OP. If any one were to drive a car of mine like that they would only do it once as I would never let them drive one of my cars again.

My mistake - it wasn't clear whether your advice was directed at the OP or was general guidance.

For reference I was a few hundred revs short of the red. The engine was 'singing' (admittedly its highest comfortable note) rather than screaming. In practice I very seldom use first for double figure speeds, preferring to use second for low-speed acceleration.

[akirk]

I was recently encouraged by an experienced driver to use more of my rev. range (z3 - 3.0l straight 6 so not a diesel!) and it is very rewarding - the auto box would choose to change up at c. 2000 - 2500 but the car only comes alive at 3000... 3rd and 4th are slightly awkward so moving from 3rd to 4th needs to be at reasonable revs to not lose that 'aliveness'/ momentum...

the car is now twice as much fun and drinks twice as much petrol!

I used to love my Alfa's handbook - which instead of telling you not to go into the red simply said - don't stay there too long! Brilliant attitude

Alasdair

[jcochrane]

I was recently encouraged by an experienced driver to use more of my rev. range (z3 - 3.0l straight 6 so not a diesel!) and it is very rewarding - the auto box would choose to change up at c. 2000 - 2500 but the car only comes alive at 3000... 3rd and 4th are slightly awkward so moving from 3rd to 4th needs to be at reasonable revs to not lose that 'aliveness'/ momentum...

the car is now twice as much fun and drinks twice as much petrol!

I used to love my Alfa's handbook - which instead of telling you not to go into the red simply said - don't stay there too long! Brilliant attitude

Alasdair

The problem I used to have with the Alfas I've owned was that I kept activating the rev limiter.