power loss

[bigknickers]

Hi gang, my 110bhp 53 plate hdi suffers from intermittant power loss, one day it'll be fine, the next it's hopeless. The MAF sensor has been disconnected for a year, no split turbo pipes, no fault codes. It'll rev past 3000 but it's as if there's a lawnmower engine under the bonnet or all the brakes are seized on (passed the MOT last week). It will only begin to rev if I bury the pedal into the floor (TPS changed 3 months ago).
I suspect the turbo solenoid (swapped with EGR one but made no difference, but as the EGR was blanked off 4 years ago the solenoid is probably also knackered)

Why don't I just permanently bypass the solenoid with the pipes, then the turbo is always actuated.................or is that a bad idea?

[GingerMagic]

Sadly that's not how the turbo solenoid works..
It uses vacuum to close ( so vacuum is always present at the solenoid when the engine is running ) and it shuts the vacuum off to release the vanes - it's a kind of over complicated backwards wastegate..!

You've mentioned what's been replaced and to be fair those are the things I would have suggested..

If you can get hold of a hand held vacuum pump then you can test all the pipes and solenoids for continuity - should be around -700mb on tickover which is what it should read on all ends of all the pipes, I think, as the ECU drops vacuum to work the bits and bobs....

Not sure what else to suggest..

[dirtydirtydiesel]

I have a similar model with similar issue's
Driving round for a year with the maf disconnected is not a good idea

I tried mine disconnected, no power below 2k then took off like a scalded cat,
Plugged it back in better but still no were near as good as 50k ago when I first had it re-mapped

I have purchased a brand new Siemens V.D.O one, will let you know how I get on.

Other stuff I have replaced which has improved maters, high pressure pump regulator, fuel rail pressure sensor & wiring

Also ordered a new turbo vacuum solenoid as mine has been making funny chuff chuff noises for a year now
Something else to look for is the vacuum pump on the end of the camshaft can go bad

If one day it great then another not so, then my feelings are bad wiring or a bad sensor or sensor's

I think you could do with a pp2k session to monitor your live values.

As I said I've had mine for 5 years & done 50k in it, I've put far to much into mine now to give up,
Mines getting a bit like Triggers brush
But that's for another post which I've not yet finished editing

[bigknickers]

Thanks for your replies..............I put a fuel pump regulator on about 2 years ago, new cam sensor and service last week.
A vacuum pump on end of camshaft.................mmmhhhh, never even knew there was one!! new solenoid valve on order

Jeez, modern cars are a nightmare!!................the solenoid valve works the other way round!!!.............I want a lovely ford escort, only 25mpg but bung some points n plugs in n she'll keep on going!!

Sadly I don't have a vacuum gauge, but if the solenoid don't work, I'll have to get one

[PeterN]

You have about the simplest and easiest to repair common rail engine, try some of the newer ones . These engines are normally very reliable but check that you actually have vacuum at the turbo actuator or at least at the solenoid by pulling the pipe of and seeing if you can feel the vacuum, if not check the pipes for leakage, they can split.

I to long for the simple cars but I wouldn't want to lose my 50+ mpg and cheaper road tax.

I must admit that the performance has dropped off a bit on mine but it has done well over 200k miles and it still gets me there, the fuel consumption is still good and I can still repair it.

Peter

[bigknickers]

Live values............oooohhhhh, that's too scary for me!!!! wish you lived near Epsom, then I could drop some nice cash in your hand and you could ram your probe right into my socket n tell me what the problem is.

Whilst on the subject of my suffering, I want to buy a BRAND NEW comm 2000, whist trying to repair mine with the little plastic springy thing, the horn cable came out it's connector, then the airbag cable came off the plug AND the wire came out the indicator stalk..............NIGHTMARE....... so although I've got the lot working, I'd like to buy a brand new one (but I can't get one)...........do we know whether I could fit a 307 or a 207 brand new unit?

[GingerMagic]

As long as the 2nd hand Comms is pre 2005 and the same functions ( front fogs, rear wash wipe etc ) then it should be okay - sellers mention part numbers but there are only 6? variants.....

Some come with ESP, but these will fit non-esp cars.

[bigknickers]

The pain increases....................tried to get home from work..................car will not rev at all, managed to limp a mile to the mechanic's on tickover revs!!! he plugged his snap on thing n it said something about a message saying misalignment timing between cam and crank sensor (he put a new cambelt n water pump at 125K)

The car has only done 130K (I've had it for 5 yrs) I'm sure it's got many more years in it BUT I'm just about to walk away n buy a Passat diesel or perhaps a 307sw petrol................bugger the MPG, reliability twists my juices every time!!!

[dirtydirtydiesel]

I feel for you I really do,
I'd stick with it, the camshaft position sensor wiring is quite fragile & prone to failure.
If you replace the sensor / sensors make sure you use genuine ones, don't have to be from the steelers though.

If you think yours is unreliable then don't buy a 307
& the VW / Audi suspension is very complex & fails at high millage .

[bigknickers]

Game over................mechanic can't find the fault (first car that's ever beaten him!!)..........gotta laugh, it's got a brand new MOT n just been serviced n only got 130K on the clock............who says they can do 500K!.............heyho ain't life random!

[GingerMagic]

That's a shame, the 406 is generally pretty robust.
I'm sure it's a really simple fix, wiring or a sensor - however there comes a point where you need to stop spending, stop pulling your hair out and think about moving on....
I understand that, if a car isn't reliable ( whichever make it is ) then time to find an alternative.

I've been chatting to my mechanic friend about what cars he feels are most reliable, and despite his German origin he says Honda or Toyota - boring but reliable.

Good luck, whatever you decide to do.

[dirtydirtydiesel]

Game over................mechanic can't find the fault (first car that's ever beaten him!!)..........gotta laugh, it's got a brand new MOT n just been serviced n only got 130K on the clock............who says they can do 500K!.............heyho ain't life random!

My money's on a broken wire somewhere

There is a post on here somewhere where the o.p had broken wires to the e.c.u after a cambelt job
You have to move / disturbe them to do it & they can be quite fragile

Sorry to here your tails of woe but if your having to pay / rely on someone to do the job I understand.

Hope you have better luck with your next purchase.

[bigknickers]

Looked about for a replacement....................£820 got me a 52 plater 406hdi estate with 115K...........couldn't get a Honda or Toyota for that money!!....................anyway, seems to drive OK except the ABS light is on..............what's that likely to be?

[caprixpack]

Could be anything from the wrong wheel bearings fitted, wheel sensors covered in crap or dead to a dead abs pump.

[GingerMagic]

Check the front reluctor rings for hairline cracks, as this is normally the culprit, if not the check the rear abs sensors inside the hubs have not been damaged by the handbrake shoe retaining pin falling out....
Other than these it's pot luck really - but diagnostic may point you in the right direction....