No oomph!

[stvpug1]

Hi, I've had a 1999 406 estate (90 Bhp 2.o hdi) for two years, its done 227k. I've also got a 406 saloon (rapier) which i've had for 10 years which has only done 90k. Same engine.
But there is a vast difference between the performance of the two cars. There doesn't seem to be any power in the estate until you get up to 2500 rpm ish, is it just down to the high mileage? or could it be something else. The saloon seems to have lots of low down power!
Any replies would be appreciated.

[gumby6371]

First of all welcome in mate,

Secondly the estate is a heavier car so obviously wont take off like the saloon.

Having said that I'd be looking first at a good fluids and filter change, dirty air or fuel filters will affect performance.
A dose of Redex or Millers to give the injectors a clean.

I don't believe the HDI 90 has an intercooler so the usual check for splits in the pipe doesn't apply so oil leakage through the turbo seals would be another place to look.

I'm sure some knowledgeable HDI owners will be along soon with some pearls of wisdom.

[stvpug1]

Thanks for reply - the filters are probably six month old (5000 miles).

[mjb]

Hmm sounds like your hdi90 estate is as bad as the one I bought last weekend. I thought it might just be the way it was made - I'd suggest maybe the saloon has had a remap, but if you've had it for 10 years I guess probably not.

I know very little about hdis at the moment, but there's five things that spring to mind which can affect performance:

1. Clogged filters - air, fuel, or maybe the one in the fuel tank
2. The air intake in the front passenger wheelarch has collapsed
3. Dead turbo (seized, or the wastegate stuck)
4. Collapsed cat element
5. Clogged injectors

[stvpug1]

I don't think it has had a remap - but it was a dealer demo approx 6k when we bought it so who knows? anyway power kicks in at just above 1000revs. Is there an easy way to tell if turbo isn't working? Exhaust and cat replaced 10k ago.

[mjb]

anyway power kicks in at just above 1000revs. Is there an easy way to tell if turbo isn't working? Exhaust and cat replaced 10k ago.

It seems we might have an identical problem here unless your saloon is indeed remapped, but I do doubt that. The hdi90 I bought last week finds its legs around 2500rpm, then loses them again before 3500... It also doesn't seem to enjoy being under 1500rpm - gets a bit grumbly about it.

This is the first HDi I've driven (bar a short test-drive in a 407) so I sorta guessed that it might be normal - all my previous 406s have been petrol and my daily drive is a V6 petrol... I've run diagnostics here, but it shows nothing wrong other than a dead glow plug relay and the speedo needle being a bit sticky between 155mph and 160... not that it could ever get there without being pushed off a cliff Of course, I have no idea what sort of faults will register on this thing.

Thinking about it, I don't recall feeling a turbo lag surge or hearing a turbo whistle at any time, although the tubby (2.0 turbo petrol) had a *completely* un-noticeable turbo (but the car was virtually undriveable with a failed turbo)

I'm not sure if the HDi has a MAP sensor I can read to check the turbo pressure, but I think that apart from fitting a boost gauge, the best way to check the turbo would be to remove a pipe and poke the impellers to see if they turn, and make sure the wastegate actuator moves smoothly. That doesn't prove the turbo system works, only that the turbocharger unit itself probably works - a valve or something could be preventing it from working

Perhaps someone more familiar with these engines can shine some light on this?

[stvpug1]

I have never heard a turbo whistle on the saloon, but there's definitely something working on this one. The mpg is very similar on both cars, around 48, so no clues there. Is it possible it is just because of the high mileage, never had such a high mileage on a car. so not sure what to expect.

[rwb]

Very noticeable boost in first: let the clutch out then put the accelerator to the floor and it's clear that the turbo arrives at 1800. Out of puff at 3000.

Are you both Bosch?

Sam and I have both recently had throttle position sensors which made it feel different.

[mjb]

Is it possible it is just because of the high mileage, never had such a high mileage on a car. so not sure what to expect.

That one I can answer authoritatively - No. These things will out-last the bolts holding them together! Yeah, that doesn't make much sense, does it? There's not much that's usually affected by high miles on a 406 other than the expected things like the clutch (150-200k on the torquier engines), rubber engine mounts, radiators, driver's seat fabric, etc.

[stvpug1]

Thanks mjb &rwb - I’ll try your suggestion tommorrow - so let me get this right - I floor it in first and should notice turbo between 1800 and 3000.
Am I looking for bosch diesel pump?

[gumby6371]

Another turbo test is find a road with a nice steady incline, change up from second to third a little too early, she should be quite sluggish and the revs should build quite slowly until you hit the point where the turbo takes over and she should start to pull better and the revs build considerably faster.

I only posted this because if I try RWB's suggestion in my car on what will probably be a damp road I just spin the fronts and snake about trying to avoid curbs and hedges

[stvpug1]

I have been out for a run, there isn't noticeable acceleration or boost from any point from idle up to 3500 rpm (maybe just a little around 2500 but a maybe imagining this, as its that insignificant) If the turbo wasn't functioning would there be black smoke from the exhaust? I haven't noticed any black smoke at all, Is there an easy way to test whether the engine management fault light is operating without any diagnostic equipment, such as disconnecting any sensors?

[mjb]

I think the eml lights up when you first turn the ignition on, but I'm not sure. I'll check in a bit

[rwb]

...the eml lights up when you first turn the ignition on...

Yes, it does. And even if it wasn't working, you'd still get warning messages on the MFD. I'd have thought that a duff turbo would at least give you engine anti-pollution system defective, if not something more exotic.

...if I try RWB's suggestion in my car ... I just spin the fronts

As you point out, essentially the same thing happens in third: foot down, slowly creeps up to 1800, then suddenly off you go leaving a cloud of soot -- most easily seen in headlights behind you.

[mjb]

...the eml lights up when you first turn the ignition on...

Yes, it does. And even if it wasn't working, you'd still get warning messages on the MFD. I'd have thought that a duff turbo would at least give you engine anti-pollution system defective, if not something more exotic.

What anti-pollution system? There's no FAP on the 90s. I can't honestly think of anything it would complain about (the petrol tubby doesn't even log a fault if the turbo had failed)