1.6 hdi mkn1 berlingo speedometer haywire

[Yomper]

Hi
I have a mk1 berlingo  1.6hdi and this morning needle started to fluctuate  then dropped to 0 then van started to just lose a bit of power like it was struggling for air just for a second every  now and then. After 5 mins of driving it sorted itself any ideas what it could be
Thanks yomper

[Yomper]

I have searched and saw it could be a sensor or the thing that goes in end of gearboz or even ECU but none say there van lost power. Unless losing power thing is just a coincidence and could be something else

[Sol]

Engine power wouldn't affect the speedo, unless it physically slowed the van down by the amount of the drop on the speedo.

Is it your rev counter thats dropping while losing power to the engine? That would make a whole lot more sense. You could be drawing air in the fuel line, or otherwise not getting fuel pressure to the injection rail - HP pump etc, turbo boost pressure coming and going etc. There are a few reasons for temporary power loss but none relate to the speedo issue (if it is the speedo)

[Yomper]

It is the speedo as rev counter is constant.
I think it could be my air filter its past due an service by a good bit. It was aBit damp last night so maybe dried out as it works fine now. Speedo is back working too so I have no idea!

[Sol]

Ok, you could have water ingress issues with the BSI or ECU then, best to keep an eye on that.

[Yomper]

Its happened 3 times now in the morning after 15 minutes the speedo works fine.
I find when I accelerate the needle drops but coasting its pretty stable.
The lack of power was just dirty air filter

[Sol]

Your Speedo is likely cable based from the gearbox and the square drive is slipping. Probably just needs a new Speedo cable, nothing sinister. They do wear out.

[cancunia]

There's a sensor for the speedo in the gearbox just by the driver's / right driveshaft. Chances are that the connector has got a bit dirty. My speedo would often not work first thing until I used the engine to slow down.

[Yomper]

Ok thank you I will.have a look