Technical Ducato tacho

[dieselmonkey]

Hi it would appear my tacho drive has chucked itsthand in and I'm struggling to find a replacement
It's a 2002 Fiat Ducato based motorhome
2.0 Td
I'm desperate
Cheers
Ian

 

[Communicator]

Hi Ian,

Can you please confirm to the forum, that you are actually referring to the tachometer (engine rpm indicator), and not the speedometer.

Failure of the former is an inconvenience, while a working speedometer is a legal requirement.

If it is the speedo cable or similar that you require, then I have read that there are still firms offering a made to measure service. I think that this service was mentioned in a similar situation some months ago. You will need the broken parts as patterns.

 

[dieselmonkey]

Hi Ian,

Can you please confirm to the forum, that you are actually referring to the tachometer (engine rpm indicator), and not the speedometer.

Failure of the former is an inconvenience, while a working speedometer is a legal requirement.

If it is the speedo cable or similar that you require, then I have read that there are still firms offering a made to measure service. I think that this service was mentioned in a similar situation some months ago. You will need the broken parts as patterns.

It is the cable drive unit mounted on the gearbox

 

[dieselmonkey]

Hi Ian,

Can you please confirm to the forum, that you are actually referring to the tachometer (engine rpm indicator), and not the speedometer.

Failure of the former is an inconvenience, while a working speedometer is a legal requirement.

If it is the speedo cable or similar that you require, then I have read that there are still firms offering a made to measure service. I think that this service was mentioned in a similar situation some months ago. You will need the broken parts as patterns.

This is the part required

 

[Communicator]

Ian,

While this will not help directly, I am struggling with the description of your base vehicle. However while the registration number is often accepted, some web search sites require full vehicle details.

You state that your vehicle is a 2002 2.0 td. Given that it is a motorhome there is the possibility of a delay between base vehicle construction and conversion.

The x230 model was manufactured until 2001, and wae replaced in 2002 by the facelifted x244. The only 2.0 diesel engine offered at that time, for both models was the common rail 2.0jtd.

The mechanical tachometer drive was used on the x230, and was replaced by an electronic system on the x244, so I suspect that your base vehicle is a 2001 x230 2.0jtd.

 

[bugsymike]

Just to add to the fun, is the plastic gear drive damaged that engages to the gear in side the gearbox or the external drive unit?
The only reason I raise this point is I believe it was Mk3 Ford Escorts that had a speedo drive problem as they got older, however it was caused by wear in the transaxle diff bearings causing the drive to not engage correctly to the external speedo drive unit. It could sometimes be detected by shaking the drive shafts where they came out of the gearbox/transaxle and noting excess movement from the diff bearings.
Hopefully yours is just a simple problem .

 

[dieselmonkey]

This is some photos of my part the problem appears to be that when the two parts are put together in the housing they can turn independently not as a driven unit if that makes sense

 

[bugsymike]

At least the gears are OK . Is it just a case of the nylon square dog not transmitting drive? So in the fourth picture the two parts are slipping?
Just a thought Peugeot Boxer was the same but badge engineered I think, which may give you more choice in the search for parts.
I have a friend down in Cornwall with a dead Peugeot Boxer in his farmyard though I doubt if he would be keen to strip parts out.

 

[dieselmonkey]

At least the gears are OK . Is it just a case of the nylon square dog not transmitting drive? So in the fourth picture the two parts are slipping?
Just a thought Peugeot Boxer was the same but badge engineered I think, which may give you more choice in the search for parts.
I have a friend down in Cornwall with a dead Peugeot Boxer in his farmyard though I doubt if he would be keen to strip parts out.

Hi bugsymike
in the fourth picture on the polished shaft with the gear at the end where the square drive fits into there appears to be some kind of green bush and this is able to rotate within the shaft therefore not transferring the drive from the gear through to the square drive and on eventually to the tacho cable and the speedometer

 

[bugsymike]

Hi bugsymike
in the fourth picture on the polished shaft with the gear at the end where the square drive fits into there appears to be some kind of green bush and this is able to rotate within the shaft therefore not transferring the drive from the gear through to the square drive and on eventually to the tacho cable and the speedometer

So it isn't a case of the square drive slipping or rounded off and so not transmitting movement from the gear end to the "magnetic rotor" that provides the signal to the speedometer?
Were you able to look up your van and similarities on wikipedia to the Peugeot Boxer of the same age and engine type to see if parts may be available from that direction?

 

[dieselmonkey]

So it isn't a case of the square drive slipping or rounded off and so not transmitting movement from the gear end to the "magnetic rotor" that provides the signal to the speedometer?
Were you able to look up your van and similarities on wikipedia to the Peugeot Boxer of the same age and engine type to see if parts may be available from that direction?

No I haven't looked anything up yet

 

[Anthony489]

Hi dieselmonkey

I am rather puzzled by all this

So we are talking about the Speedo and not the Tacho

Your photos seem to show something with a rotating magnet, which would produce electrical impulses to drive an electronic speedo, i.e. one that doesn't have an old-fashioned flexible mechanical cable drive.

If so, there should be minimal mechanical load on the plastic gears, all they have to do is spin that lightweight magnet

The 4th photo is hard to see, but it looks like the upper and lower parts are joined by a square plastic shaft poked into a square hole in each. Is this plastic part OK or has something jammed and caused it to round off ? If its simply a plain square section piece, one could make a new one from non-magnetic material such as aluminium. Plastic parts in contact with oil do degrade and weaken over time.

At least the gear looks unscathed, and by implication the mating one in the gearbox is OK.

The parts drawing doesn't tally well with your photos, but in my experience they do sometimes have some artistic license and/or don't get updated when things are modified.

 

[dieselmonkey]

Hi dieselmonkey

I am rather puzzled by all this

So we are talking about the Speedo and not the Tacho

Your photos seem to show something with a rotating magnet, which would produce electrical impulses to drive an electronic speedo, i.e. one that doesn't have an old-fashioned flexible mechanical cable drive.

If so, there should be minimal mechanical load on the plastic gears, all they have to do is spin that lightweight magnet

The 4th photo is hard to see, but it looks like the upper and lower parts are joined by a square plastic shaft poked into a square hole in each. Is this plastic part OK or has something jammed and caused it to round off ? If its simply a plain square section piece, one could make a new one from non-magnetic material such as aluminium. Plastic parts in contact with oil do degrade and weaken over time.

At least the gear looks unscathed, and by implication the mating one in the gearbox is OK.

The parts drawing doesn't tally well with your photos, but in my experience they do sometimes have some artistic license and/or don't get updated when things are modified.

 

[dieselmonkey]

Hi Anthony
The van is fitted with a cable and the small rotating magnet used for what i don't know but the speedometer is driven by the cable ,
the metal shaft with the gear on it at the opposite end has a small plastic piece inserted in the end which is hard to see
the square end fits in this end however when the pieces are put together and you hold the small magnet you can rotate the gear end so therefore no drive from one end to the other.

I've taken a video which i'll post from my phone and hopefully show what i mean

 

[dieselmonkey]

Hope this explains a bit better

 

[bugsymike]

Hope this explains a bit better

I can see better from your video now.
On the gear end that is slipping I see there is a knurled section, do you think it would be possible to carefully grip it and see if that part unscrews or can be tightened to transmit more grip? Presumably it is knurled for a reason.

 

[Anthony489]

Hi

Thanks for the update. It looks as though the speedometer is conventional but there is also a "pulse generator" to send road speed data, probably to the ECU.

If you can't source a replacement it would be tempting to get an engineering shop to install a tiny grub screw or roll pin to hold the insert into the metal sleeve.

 

[dieselmonkey]

I can see better from your video now.
On the gear end that is slipping I see there is a knurled section, do you think it would be possible to carefully grip it and see if that part unscrews or can be tightened to transmit more grip? Presumably it is knurled for a reason.

I thought that but I'm unable to move it either way

 

[dieselmonkey]

Hi

Thanks for the update. It looks as though the speedometer is conventional but there is also a "pulse generator" to send road speed data, probably to the ECU.

If you can't source a replacement it would be tempting to get an engineering shop to install a tiny grub screw or roll pin to hold the insert into the metal sleeve.

That isn't an option as both parts go into a plastic housing one from one end and the other from the opposite end

 

[bugsymike]

I thought that but I'm unable to move it either way

If not possible to undo knurled end and the green plastic appears to slip in the geardrive, would it be possible to see if a small flat screwdriver gently down the square hole whilst turning the drive could encourage the plastic to wind out of the hole to give you a better look at how it was originally secured.
If it did come out and it was all thoroughly cleaned with alcohol or similar, maybe some araldite or similar in the hole might stick it.
Just a thought as nothing to lose if it doesn't work anyway