406 Hdi not reving past 2400

[Quinncy]

Hi, Ive been having a problem with my 406 hdi 90 now for a few weeks, almost ready to send it to the scrappys. The problem is it won't rev past 2400 ive had it's fault codes read and a few came up. There were a few tho the engine light has been on since i bought the car 4 years ago. The faults were fuel low pressure pump supply; short circuit to earth or open circuit, 3rd piston deactivation device; short circuit to earth or open circuit, egr; open circuit or short circuit to ground, fuel pressure sensor circuit; short circuit to ground

Ive already changed the 3rd piston deactivation device with no change and also egr valve with no luck. I took the Fuel pressure sensor off and the plastic part wasn't straight on the metal part of the conector there was a slight bend where the plastic conector part joined the metal part not sure if it's ment to look like that. I then fitted the fuel pressure sensor back and started the car with out it wired up and there was no change in the way the car run which is leading me to belive that could be the problem only thing is I don't want to spend anymore money on the car unless I can be sure it will work, the cars not really worth a lot now. Has any one any idea how it would run with the fuel pressure sensor disconected?

[GingerMagic]

HI, don't mean to talk down to you or anything but have you tried the basic stuff like throttle cable slack ( common problem ) or throttle position sensor ( more common problem ) ?

Sounds like you know what you are doing, there are a few chaps on here who may have some wise words....

My old 90 never went above 3000 rpm, turns out it was only ever getting half throttle because the cable clip was too far from throttle body...

[Quinncy]

Yeah had a look at the throttle cable all looks fine, not really tried the tps it never came up on the fault code. Ive checked the in tank pump and works fine. Still think it could be the fuel pressure sensor or maybe thinking it could be the high pressure pump but unsure of how to test.

[madmadmax]

i have a feeling this is a bit more than a slack cable but its worth a check, to start with check continuity and that the cables are plunged in an not traped or have water in the connections and that the correct plugs are in in the correct sensor. we will leave the egr valve for the time being as it a non required system and should not affect the others

the unfortunate this is that you will have to get the codes removed to see if swapping anything round has worked

[rwb]

That's quite an unusual collection of codes

Usual method is to clear them all, then see what comes back when you drive it.

That fuel pressure sensor sounds most likely. As you point out, if the car behaves the same with no sensor as it does with a broken sensor (I don't know) then your test didn't prove anything.
Looks like they're about £25 on eBay, so worth a try?

[Quinncy]

It was cleared and that was what came back. Just wondering what anyone else experienced when the fuel pressure sensor was disconected or not working. Ive ordered a sensor from ebay to try, really hope this works an i'm running out of ideas.

[rwb]

It does sound very likely, so fingers crossed...

[Quinncy]

Thats it fixed. It was the fuel pressure sensor under the fuel rail. Hope this helps people with the same problem.