PEUGEOT 406 HDI WONT REV??

[chris18]

Hello everybody im new to the forum i have this problem with my 406 hdi it starts ticks over fine but wen i press the pedel to rev it its dead as though im not even pressing anything its had a new throttle unit 2day but still exactly the same please need help lol anyone any ideas??. cheers chris

[mjb]

its had a new throttle unit

Do you mean throttle position sensor?

[chris18]

hiya mate its the one with the cable that goes to it that i replaced

[steve_earwig]

That's the throttle pot, they ain't cheap either! (Paging Mr Welton...)

Hi there, I'm not sure but looking about on the 'web the advice is to check the connections on your engine management ecu (or change your alternator ).

[chris18]

cheers mate ile check everything again 2moz. thanks chris

[Longintooth]

Hi
I know you might think this a Tad insignificant but first a Diesel does not have a throttle as in a petrol - the control operates a simple electronic variable switch to the injectors (in old diesels it used to control the injection pump)via the ECU. Alas to monitor the operation you need a scanner. However, you can do preliminary checks on the control unit. Check the socket connections and the obvious cable attachments. I'm not sure if this unit needs pairing with the ECU so if you have fitted a new unit this could be the reason. But before you do anything just ask the the stealer to confirm this. On the right hand side of the engine compartment there is a fuel cut off switch reset button with a red cap you could try pressing this. If you can get an oscillator or digital multimeter connected to the unit you can confirm the signals are being sent.

[steve_earwig]

Err, he's checking the connections, service box doesn't mention anything about setting the throttle pot up and I don't think he'll have picked up another duff pot (although stranger things have happened...). Why would the fuel cut off affect the engine revs? (apart from not actually having any)

Btw if anyone can't find their cut off it's probably absent - they don't all have one (neither of mine do).

[mjb]

Alas to monitor the operation you need a scanner.

An oscilloscope, analogue voltmeter, or at a push a digital voltmeter/multimeter will do the job fine. The throttle pot is just a potentiometer - three wires: GND, V+, and a line that varies GND<n<V+ dependent on throttle position

[mbell666]

Could it be the intank fuel pump? enough pressure to idle, but not enough to get the revs up?

is it a 90 or 110?

[Longintooth]

Hi
Well if it was a restriction on fuel I think you would get a blip like a flat spot before dying back - this sounds like there is no reaction from the potentiometer.
It's one of those cases where an electrical test is required then just keep tracing. My 110 Hdi does have a fuel cut off I imagine some others may not. But I suggested that although I am aware it usually does not start at all if its been tripped as on many Citroens. But who can say what Peugeot have introduced. I cannot find any reference to suggest it has to be paired but who knows.