manually up shifting

I try to manually up shift to keep the RPM's down, but it doesn't seem to respond right away. It also doesn't seem to respond with concistancy.
What does your van do?

Expert Marine said:

I try to manually up shift to keep the RPM's down, but it doesn't seem to respond right away. It also doesn't seem to respond with concistancy.
What does your van do?

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The Upshift depends on engine temperature and acceleration. procedure.

It has gotten colder around here and in the morning it seems that it does not want to upshift at all until the RPMs are maxed out for each gear. Pushing the stick does nothing or only very late. The engine also seems to have less power and accelarates very slowly unless I really step on it which is not preferable.
Once engine has reached operating temperature it seems to upshift on command with very little delay. That is if I am not going up the hill and/or are stepping on it.
It is after all an automatic which other wise shifts very smoothly.


Cheers SprinterUSA1

I don't normally pull a trailer but tonight after our race I had to haul my brother enclosed tandem axel bike trailer. As soon as you hit the road my up shifts go from around 2500 rpm up to around 3300 rpm. I wish it was like my Baja and after a preset rpm it will let you up shift.

Expert Marine said:

I try to manually up shift to keep the RPM's down, but it doesn't seem to respond right away. It also doesn't seem to respond with concistancy.

Click to expand...

The "manual shift" commands are more of a "suggestion" to central command that you want shifts now. Sometimes it will take your advice-other times it knows (or thinks it knows) best. If you're really impatient with its response time, try holding the stick -for a few seconds- in which ever direction you wish the shift to go. That seems to get attention. Doktor A

abittenbinder said:

If you're really impatient with its response time, try holding the stick -for a few seconds- in which ever direction you wish the shift to go. That seems to get attention. Doktor A

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In the 2007, it will upshift to 5th or downshift to 1st (from whatever gear you are in) if you hold it in the correct direction for a few seconds.

Herr Doktor..... I agree with you, and would add this: If you want an upshift it will get more attention in the grand scheme of Sprinter computer control if you also let off of the accelerator slightly!

It seems to understand that a conflict between your request for more power and acceleration (foot feed as we call it in the southern USA) and your (lower priority) request for an upshift (+ stick jog) requires a decision and it decides to keep power/turbo going and wait on the shift a bit longer.

You can almost get the early shift better by letting off on the accelerator and then touching it again just before the Sprinter "wants" to shift on its own... but, done suddenly, the Sprinter may see this as a request for staying in the same (lower) gear and allowing engine braking. This is by my own experience, not by technical analysis of the engine/transmission program.

KenB

True if at a stop, but not true if you are running at a speed which the computer sees as an innapropriate time (won't go into 1st at 50 MPH, for example). Also won't actually be in 5th at 20 MPH (will show top gear in window, but will be in 4th or maybe 3rd).

Yes, shifting to 4th will sometimes cause a downshift at 25 MPH (when the shifter shows 5th), but this seems to be due to some other factor as the 5th gear on my auto has never been engaged at 25 MPH (except maybe pointing straight down hill)... But if it had been in 5th at 25 MPH, it would be accelerating due to the lack of engine control over the sitiuation (lots of gravity to push the vehicle faster than the 5th gear would ever slow the van down). Idle in 5th is faster than 25MPH.

Thanks,
KenB

**** computers think they are smarter then us...
Ever watch I-robot?

Just wish it was more responsive...

KenB said:

Herr Doktor..... I agree with you, and would add this: If you want an upshift it will get more attention in the grand scheme of Sprinter computer control if you also let off of the accelerator slightly!

This is by my own experience, not by technical analysis of the engine/transmission program.

KenB

Click to expand...

Excellent point Ken. Throttle position(load demand by driver) is an important parameter and will get central commands attention. Doktor A

Thinking of the above
Plant your foot from a standing start Trans seems to have definite shudder or jerkiness to it's operation Up-shifting on a gradient%+ slow reaction for a few brief moments almost like a slight turbo lag , down Gradients%- has a stall factor at different RPM's at 57 MPH.
{ ASR }Acceleration Skid Control...Works in the same way as {ABS} Anti-Lock Breaking System...In that it detects and avoids wheel slip.
The only difference is it detects the wheel driving rather than breaking, and that! Instead of, reducing the breaking as in ABS..ASR reduces engine torque.
ESP + ASR stabilizes the vehicle by breaking individual wheels, and limits the engines out put.

Quoting direct from My manual
Unique: Adaptive ESP
The standard-fit ADAPTIVE ESP improves handling stability, especially in critical situations.
ADAPTIVE ESP continually calculates and takes into consideration the vehicle load at any given moment.
The system integrates anti-lock breaking system.
{ABS} acceleration skid control {ASR} electronic barke force distribution Force,{EBV}, and brake assist system ,{BAS}.
Stabilization through precise intervention in brake, engine, and transmission control....End Quotation.

Hit the accelerator at high rpm, there is a slight stall and then shudder at the transmission , but it is the rear end breaking forces, of anti-slip of the wheel that causes this slight shudder.
Deactivate the ABS and BAS, ESP is still active but slower to react, and repeat the process, the wheels smoke , spin and the van flicks, left to right, if empty.
The van is more responsive under testing, but you in effect disable, the safety features.
Testing this on the track using onboard computer assist showed many variables at different RPMS up hill, down hill
Just my two cents worth.
Richard