406 diesel air intake

[HDi fun]

I have a minor oil loss from the air 'doser' - it's the device in the intake side that chooses whether to feed the car cooled air (from intercooler) or the hot stuff directly out of the turbo.

It has been replaced about 35,000 miles ago to solve the same problem. I'm told that the problem is relatively common on remapped 406 diesels (of which mine is one). I'm guessing due to higher intake pressures overcoming the resilience of the device and it's seals, gaskets etc.

The car is a 2.2 HDi with a custom remap which basically increases fuelling and boost pressure across the rev range but in a progressive way rather than the brutal changes that plug in boxes do. In turn this gives more torque and thus more power and more performance.

Can I get around this problem by fitting an intake kit? Would doing so interfere with the operation of the particle filter? Or would it not solve the problem because the intake kit doesn't replace the air 'doser' (it's a French to English translation) ?

THe obvious answer is to reload the factory fuel/boost map but I do like the extra torque that the ECU remap provides.

The oil loss is fairly small and I don't need to top up between 12,000 mile services - perhaps I should put up with it and just jetwash the front of the engine occasionally?

Any ideas?


Thanks,

Regards,

Paul.

 

[obi_waynne]

I'd look at the oil seal additive. It bonds and rejuvinates rubber oil seals and I think it is made by the same people which do slick 50. It might be all that you need. I doubt that an induction kit would solve the problem for you.

Rather than replace the unit can you just take it off and replace the gasket?

You could always just drive it slowly

 

[HDi fun]

Is it safe to use oil additives?

 

[obi_waynne]

The rubber reconditioning ones work well. I think the question should be "do oil additives work" rather than is it safe. Many additives seem to be a bit of a con and claim to have lubricants which bond to the metal work of your car.

As the rubber gets old it starts to shrink, this additive rejuvanates the seals and is just a harmless liquid as far as the other parts of the engine are concerned. If you have doubts put some in a few hundred miles before the next oil change is due.

 

[HDi fun]

Problem is that the component that's allowing some oil out is not connected to the engine oilways directly. And it has been replaced before.

The oil it's shedding is from that fine mist of oil that all turbochargers to discharge on the high pressure side of the intake (between turbo and mainfold).

The rest of the engine is totally sealed and there is no oil loss from 'proper' oil seals.

I have an idea that it's been overfilled at the last service which has caused the problem. I recently jetwashed the engine (brave) and it's stayed clean so maybe the very slight overfill has been discarded via the turbo.

I still think that the higher boost pressure has contributed to the problem, but that it's not the root cause.

There's no loss of turbo boost pressure.

 

[obi_waynne]

I wondered how an air pipe was leaking oil. That makes more sense now.

 

[HDi fun]

It took me several bites too when I was told this as well.

Perhaps just drain the oil out and replace with potato peelings
​

 

[obi_waynne]

Potato Peelings and hot oil - chips!!

 

[jarrus]

Personally I would just remove it and have the air running though the intercooler all the time obviously your turbo is creating enough pressure to warrant one so why would you need to bypass it?

I don't know about anybody else but it jsut sounds like a useless bit of hardware (not the car that 'doser' thing) I have a Peugeot Turbo diesel and i don't think my car has it...

Having said that I think I know what it's actual purpose is. It's something to do with burn all the soot out of the particulate filter...there an article on this site somewhere about it so i won't go in depth about it...

but still; i would bugger off the particulate filter and the 'doser' thing and jobs a good'un..lol

 

[HDi fun]

That's exactly it - it's the bloody particle filter that requires this stupid pice of kit. I had the filter replaced at 50,000 miles so it's due again soon.

How about: a nice simple piece of straight pipe on it's place and some digging in the BSI code to tell it to totally ignore the pressure sensors?

 

[jarrus]

That's exactly it - it's the bloody particle filter that requires this stupid pice of kit. I had the filter replaced at 50,000 miles so it's due again soon.

How about: a nice simple piece of straight pipe on it's place and some digging in the BSI code to tell it to totally ignore the pressure sensors?

Bloody right mate...just do it...will be cheaper all round...lol

 

[memphisto]

That's exactly it - it's the bloody particle filter that requires this stupid pice of kit. I had the filter replaced at 50,000 miles so it's due again soon.

How about: a nice simple piece of straight pipe on it's place and some digging in the BSI code to tell it to totally ignore the pressure sensors?

hey mate new here and am sick of having the anti pollution fault come up on my 406 2.2 hdi, have replaced the FAP and now 20'000 miles on im getting the fault again

ive been told the codes that are coming up are something to do with the wiring harness and another to do witht eh throttle petentiometer or something ?


anyway i would love to just have the FAP removed and replaced with a striaght pipe but cant find anyone who knows how to do it. Aopparently on other diesels a simple Chisel throught he FAP works hwoever due to the pressure sensors this is a no no on the 406 !

 

[HDi fun]

My filter was replaced at 55,000 miles. I subsequently discovered that this was because some stupid Ford dealer who serviced it used a semi synthetic oil. This is a No No apparently. You must use a fully synthetic low ash formulation. Having switched to such an oil after the FAP was replaced I have had no further problems with it and I now have over 125,000 on the clock.

You do still need to get the Eolys reservoir replenished when you get the 'DIESEL FUEL ADDITIVE LOW' message on the display. It's also necessary to reset the ECU flag so it knows this has been done.

The best wasy to operate these cars is to drive 'em fairly hard from time to time, obviously let it warm up first. If it starts one of its regeneration cycles then drive through it - don't switch off is the unofficial but very good advice.

The throttle potentiometer is the Peugeot halfway house drive by wire system. Throttle cable from pedal goes to throttle quadrant under the bonnet. It's mounted to the right of the cyl head as you face the car.

It's a dual track sensor - one has failed. The replacement part is about fifty quid. Again - you'll have to reset the fault light.