Speedo works intermittently

[dieseldave]

I get into car and speedo doesn't work most of the time.

However when it kicks in mid journey car seems to pick up power, and similarly when it goes again I seem to lose power. Does this sound normal?

Problem seems to lie with sensor on gearbox, but is the pick-up/loss of power normal?

Car is 110 hp 2.0 hdi executive saloon btw

[jonsowman]

When the ECU can't determine road speed it'll limit injection quantity. Briefly, it's because it can't tell whether the car is in gear or not and doesn't want to risk overspeeding the engine.

As such, yes it's normal to have these symptoms. Change the sensor and it'll be back to normal

[dieseldave]

Like the coupe in your sig.

Going to get the sensor in over the weekend, then next on cars is a mild remap. Don't want to go too far, or end up pushing out too much smoke. Would say a map to in the region of 140 bhp or so be the most sensible option?

Also does anyone know if there are silicone boost hoses available for the 110 hdi engine, need to change one and thinking if trying to get a bit more power out of it, I might aswell upgrade the boost hoses

[KozmoNaut]

As such, yes it's normal to have these symptoms. Change the sensor and it'll be back to normal

Just to add to this, when I had the problem same on my car, it wasn't the sensor itself, but rather the control box behind the glove compartment.

Same symptoms, but the fault can happen in two different places in the signal chain. Cost me about £60 to have my mechanic fix it, and according to him it should be a permanent fix, apparently PSA changed the design or supplier at some point.