Help 406 hdi won't rev past 3k revs

JonnyH · Post by **JonnyH** » Tue Jul 10, 2012 9:37 am

Hi hoping someone can help. My 2000 406 90hdi has developed a problem. Over the last year or so the car would develop a lack of power every now and then for no apparent reason. It could last for a few minuits up to an hour. The frequency of this has increased and now on my last drive it seems that the car won't rev past 3k revs at all and has a serious lack of power getting to 3k too. It does the same thing driving or without the car moving. The power loss is very apparent although it does run tick over and drive fine to 3k. Help greatly appreciated on this as we are in a very remote part of Scotland with little access to reliable mechanics.

Thanks

Post by **steve_earwig** » Tue Jul 10, 2012 11:44 am

Hello. It sounds like the car is going into limp home mode (i.e. there's some sort of fault so the car goes into a back up program to limit puwer and force you into a wallet-emptying session at the dealer's). It could be the MAF sensor, it could be something else but without some proper diagnostics (know anyone with a code reader?) you'll just be replacing parts until the fault goes.

RayneR · Post by **RayneR** » Wed Jul 11, 2012 7:33 pm

It can be down to the small "denso" sensor on upper right of the engine radiator, its attached into the chassis body you can spot it right away. IT says Denso on it ..

You your car is running fine, try disconnecting this sensor .. you probably will have the same symptom ...at least i can reproduce your symptom doing this ..and my friend also had the same problem and it was this sensor ..

JonnyH · Post by **JonnyH** » Sat Apr 06, 2013 7:35 am

ahhh, thats great I will take a look at the sensor when I get a monent. Its still doing it but less frequently now, its still very frustrating

Post by **Bailes1992** » Sat Apr 06, 2013 8:14 am

Could be as simple as a blocked fuel filter!

If it was in limpmode then I'm sure the engine management light would be on.

mjb · Post by **mjb** » Sat Apr 06, 2013 9:04 am

Bailes1992 wrote:If it was in limpmode then I'm sure the engine management light would be on.

You'd think so, but at least on my Golf it didn't light the eml... stupid thing would reliably do it if driving at 70mph for any amount of time.

rwb · Post by **rwb** » Sat Apr 06, 2013 9:49 am

Do you get a bong and a message on the MFD when it happens?

A new fuel filter is always a good idea, but my feeling is that this is unrelated.

The next step is definitely to get your fault codes read. All mechanics should have generic code readers these days; mine charges £20 for a session with it. Write down the fault codes, you can look them up here although the scanner should give some descriptions.

Ideally, clear all the codes, go for a drive, have the problem re-occur, and get the codes read again. This way you know which codes are generated by the fault.

The best case scenario is that the codes point to a single sensor, and replacing it solves the problem. (Whenever I get limp mode it's always been the throttle position sensor. I'm on my third now.)

GingerMagic · Post by **GingerMagic** » Sat Apr 06, 2013 12:50 pm

Hi, try taking up the slack in the throttle cable - or cleaning out the throttle position sensor, a 5 minute job.

Worked for my 90.

JonnyH · Post by **JonnyH** » Sat Apr 06, 2013 2:10 pm

Ok, I will try that with the throttle cable. Its quite an intermittent thing, its can happen for 5 seconds and then clear or it can continue till I get home or it can come and go as Im driving.

Cheers

madmadmax · Post by **madmadmax** » Sat Apr 06, 2013 2:47 pm

i have a code reader and can do live diag

i am in Sheffield, south Yorkshire

womble171 · Post by **womble171** » Wed Apr 10, 2013 5:27 pm

Don't know if it's the same set up as the 110 but I have the same problem with mine....
I blanked the egr off with a template made out of a beer can and I had an immediate fix to my problem

500 miles in though and the problem has just returned

Got the code P0246 turbo pressure low...
I gonna whip the egr off the weekend to see if the can has burnt through with the heat, I imagine it gets hot in there!
Another possible from what I read somewhere (i think) are the vacuum solenoids on the bulkhead, I swapped mine over with the egr one as that's not doing nothing now but still no joy??

Think it's time to get shut of my white elephant now, although it runs brilliant, just slow gettin there

JonnyH · Post by **JonnyH** » Wed Apr 10, 2013 6:26 pm

Just driven a 600 mile round trip with absolutely no problems. I also thinking that it may be happening a bit more in the wet, which seems to point towards electrical. I will try these fixes once I get some spare time and post the results. Have quite a presssing problem with a 406 td with a blown turbo and a clanking noise if anyone has any ideas.

womble171 · Post by **womble171** » Wed Apr 10, 2013 6:30 pm

Can't help ya on that one mate, sounds like yours is doing better than mine anyway

Water ingress to the drivers footwell maybe???

406oc.co.uk

Help 406 hdi won't rev past 3k revs

Help 406 hdi won't rev past 3k revs

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Re: Help 406 hdi won't rev past 3k revs

Re: Help 406 hdi won't rev past 3k revs

Re: Help 406 hdi won't rev past 3k revs

Re: Help 406 hdi won't rev past 3k revs

Re: Help 406 hdi won't rev past 3k revs

Re: Help 406 hdi won't rev past 3k revs

Re: Help 406 hdi won't rev past 3k revs

Re: Help 406 hdi won't rev past 3k revs

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Re: Help 406 hdi won't rev past 3k revs

Re: Help 406 hdi won't rev past 3k revs