406 hdi 90 only reving to 3000

[markr793]

i have a 406 Rapier hdi 90 bhp registration no.w141ona Year 2000
it was fully serviced on the 28/8/09.
it has now developed a fault,the engine management light has now come on ,and will only rev to 3000,this has been diagnosed by a garage as low fuel pressure.
I know that it has 2 fuel pumps, 1 in the tank the other on the engine both are Bosch.It starts & ticks over at idle no problem.


can anybody provide a possible answer to this problem and a solution

regards markr793

[DaiRees]

Hiya Mark, welcome to the club! Sorry mate, we seemed to have missed this one...

Engine Management Light and 3000RPM limit = "Limp home mode"

Have you tried a search on the forum, I'm sure we've had similar issues before

Sorry I can't offer any more more help (not a HDi owner), but I'm sure someone who knows about these things will be along soon....

[Doggy]

AFAIK the only fuel pressure sensor is in the high pressure circuit, (in the common rail).
High pressure pumps are generally very reliable, but also very expensive, so I would try to eliminate everything else first.
Low pressure pumps do fail, but generally it won't start, rather than perform badly - also tend to get noisy before dying.
I'd be tempted to check there's no water in the filter bowl, change the fuel filter and make sure you dont have a blocked vent on your tank, (try briefly running it without the filler cap). Next, I'm not sure - maybe swap the pressure sensor?
Things that can cause EML / limp mode include:
REDUCED FUEL FLOW
This downgraded operating mode limits the fuel flow and the engine speed cannot exceed 2200 rpm (with the injected fuel flow being less than 30 mm3).
The injection system switches to "reduced flow" mode when a fault is present on one of the following components:
· high pressure fuel sensor,
· fuel pressure regulator/sensor coherence,
· accelerator pedal sensor N°1,
· accelerator pedal sensor N°2,
· inlet manifold pressure sensor,
· air flowmeter,
· exhaust gas recycling function (regulation),
· high pressure fuel regulator,
· stability of the ECU 5 volt supply,
· diesel injector fault (1 - 4),
· inlet pressure,
· turbocharging function
The above list is for my HDi 136, but yours will be braodly similar