Author Topic: Correct Selespeed Pressure?  (Read 420 times)

0 Members and 1 Guest are viewing this topic.

Rafael Oom

  • Newbie
  • *
  • Posts: 4
Correct Selespeed Pressure?
« on: December 14, 2021, 10:27:23 PM »
I have recently acquired a 2009 147 Selespeed and have started tinkering. There is a lot of information online about this question but my situation doesn't seem to match the experience of others. According to what I have read the pressure in the Selespeed unit should sit between 45 and 55 bar. However I have checked the parameter with Multiecuscan and my readings are between 37 and 48 bar.

When the pressure hits about 37 bar the pump starts and turns off when the pressure is about 48 bar.

Is this correct? I have no issues with the transmission at all, it runs smoothly. The Multiecuscan software is connecting to the Marelli SELESPEED CFC208F (1) Automatic Gearbox.
« Last Edit: December 15, 2021, 09:55:48 PM by Rafael Oom »

CitroŽnbender

  • Hero Member
  • *****
  • Posts: 1481
  • Gen. 3:19
Re: Correct Selespeed Pressure?
« Reply #1 on: January 09, 2022, 07:07:23 AM »
Pump cycle time is probably your simplest quantifier of system health. With the ignition on, car in N, listen under the bonnet for how often the pump runs. With a new accumulator mine was 9.5 minutes, as this component approaches four years itís just over 8 minutes.

The second easy test of system health is whether the pump can run long and strongly enough to complete a full self-calibration routine.

You might unplug the pressure sensor and examine the connector in case fluid is leaking through internally like some oil pressure units. This would be unusual but might explain the low range of readings. I changed sensors when confirming my accumulator had failed and the difference in calibration was well less than 2 bar, from memory.

Rafael Oom

  • Newbie
  • *
  • Posts: 4
Re: Correct Selespeed Pressure?
« Reply #2 on: January 11, 2022, 10:14:37 PM »
Good evening, thank you for replying.

I have observed the time between the pump running and it is around 2 minutes with the engine running, stationary no gear changes and 8 - 9 minutes with the car off. I have made some graphs (attached). I can change the gears 2 - 3 times before the pump runs. When you say 9.5 minutes with the ignition on, did you mean with the engine running?

I have upgraded Multiecuscan and run the "Production/Service final calibration" under the adjustments. It does complete the task with a "Correct" message at the end but just after the clicking starts "Gearbox failure" shows on the dash. But it keeps running for sometime before "Correct" appears in the software. Not 100% sure if this is an issue.

I know what you mean by oil leaking through the diaphragm of pressure switches. I unplugged the sensor and couldn't see any leakages but gave it a clean with contact spray anyway. Even if the switch was sending a faulty reading would this affect the when computer activates the pump to turn on/off? I would think the computer would just react to these readings.

I did see on a Fiat forum someone mention that the units in some of them (not sure of the model) runs between 38 bar and 48 bar. But looking at photos online they look like different units.





warsch

  • Full Member
  • ***
  • Posts: 198
Re: Correct Selespeed Pressure?
« Reply #3 on: January 13, 2022, 03:29:17 PM »
The graph looks about right. So are the timings for the pump working.

Actually, as far as those methods are concerned, your unit is in good shape.

One thing to note - you also need to check and adjust clutch rod length, it's one of the parameters and adjusting is with a spanner on a selespeed clutch rod, if necessary. If memory serves me right, it has to be as close as possible to 28.5 mm.

Rafael Oom

  • Newbie
  • *
  • Posts: 4
Re: Correct Selespeed Pressure?
« Reply #4 on: January 13, 2022, 10:01:24 PM »
The confirmation is appreciated, thank you.

As far as the operating range goes for the pressure I guess it is OK. I just wanted to pre-empt any issues considering the range was different to what seems to be the norm online.

I am looking into the clutch rod length and the associated adjustments. The consensus is 28mm to 28.5mm, based on you comment I am on the right track. This style of transmission is new to me so want to be 100% informed before making any physical changes.

Another one I am unsure about is the "Clutch self-calibration enable". The instructions in Multiecuscan say to do a pick-up in 1st gear with the accelerator pressed ~25% for 300m. However, again online, the instruction seems to be drive in 2nd gear until 3000rpm. I'm not sure if this is necessary but is mentioned often in conjunction with adjusting the clutch rod.