Turbo does not kick in - suggested ECU fault?

[seasonshu]

When I first went onto a longer ride, I realized that the car will not accelerate and it's difficult to get top speed over 65mph. When the pedal is floored, lots of black smoke is coming out in the rear. Diagnosis: turbo does not work.
Sorry for my wordings below, however I don't know much of the topic so I will try to write my best about what I heard.

Now, the car spent a couple of days at the local garage and I believe they went through the intercooler pipes, wiring, etc. The guy was pointing to these two devices on the picture (sorry, don't know how they are called), behind the engine.

DSC07648.JPG

- he tried sucking (blowing?) one of the pipes -- the turbo kicked in.
- the given part was replaced to another 2nd hand one -- no change in behaviour.
- if they connect the two pipes, the turbo will kick in, however that way it is unregulated? -- so not a solution.
- they checked the wirings -- all seemed to be in order
- his final thought was that it must be an ECU fault and thus it must be reprogrammed -- he said the unit would need to be sent to Germany or wherever and it will cost around £350... the end bill _can_ be £700 to fix this problem. He said very few people can write the ECU - felt doubtful? (http://www.chiptuners.org/?p=13)
- He showed me the error codes he got, one of them was 'turbo failure' (other 3-4 are to be ignored according to him) -- unfortunately he cleared them before I was able to tell I need them!

Now I need a way forward please. Obviously I don't want to spend a fortune but I'd like to fix this.

viewtopic.php?f=1&t=16979&p=167193#p167042 states 5 possible reasons -- with the analysis above can I assume they don't apply? For the record the front passenger wheelarch is resprayed, that area was definitely was involved in an accident in the past. However, if the turbo is working with the hacks mentioned above it should not be the cause.

Also, what would happen if I wanted to reset the ECU -- which might happen if I disconnected the battery? Could that be any help?
viewtopic.php?f=1&t=15454&p=149392&hili ... bo#p149432

I read in other threads that the MAF sensor could be faulty. Could that be a case for me? If so, where do I find it? Do I unplug and see if it solves the problem?

Any ideas would be appreciated. If you have further questions, please ask, I can consult with the mechanic investigated with the problem. He is very helpful.

[lozz]

couid be anything mate, total guessing game from here sorry

couid be the sensor the denso one,

Have you got any fault codes ?

viewtopic.php?f=1&t=18305&p=181893&hili ... or#p181893

or is it just a vacume problem,.
have you checked or had all the pipe work checked, my way of thinking is it gets it initial vacume from the servo, the ecu opens and closes the solenoids..ecu dosent supply any vacume / ithink theres a t-peice conector, which goes to the servo,
but imight be miles out there,

sorry iknow not much use eh

[seasonshu]

Thanks Lozz.
Me knowing nothing of this, was trying to describe what they told me. Unfortunately I don't have any fault codes..
The pipes were the mechanic's first thought and then two days later the wiring. He said it's all been checked.
He also mentioned that with the above workarounds (sucking / connecting the two pipes(?) together) the boost is present, so there should be no leakage / power supply problems.
He believes that for some reason the ecu does not allow the turbo to switch on..
I just bought the car and many things have already been renewed so it would be nice to keep it..

[Welly]

Firstly, Turbo failure is extremely rare on the HDi (pretty much unheard of) so this is good news.

There is no real reason in my opinion why your ECU would be at fault and have to be 'reprogrammed'.

There's lots of other reasons that could be causing this, here's a few off the top of my head:

Diesel engines cannot produce a Vacuum like Petrol's can because there is no throttle/butteryfly so they have a separate pump driven off the engine.

Vacuum Pump - could be losing Vac and not enough to actuate the Turbo properly. The pump is mounted on the right-hand side of the camshaft (try pumping the footbrake like mad with the engine running - it will go quite firm and then keep your foot pressed on the pedal - you should feel it 'relax' as the Vacuum catches up) if the pedal stays very firm then the Vacuum system is slow.

Vacuum Leak - could be any of the Vac hoses.

Throttle Position Sensor - can give faults but normally brings on the engine light.

Boost Sensor - on top of the Intercooler might be faulty.

ECU multi-pin plug - the huge connector can suffer with corroded pins. I would not recommend 'playing' with this if you are not experienced.

I think it would be best to consult a Diesel Specialist or even pay for a 'Global Test' (a full fault code diagnosis) at a Peugeot Dealer otherwise you could go around replacing things that were not needed.

[seasonshu]

Lozz, I keep laughing at your avatar

Anyway, I tried two things:
1) viewtopic.php?f=1&t=18305#p181893
to disconnect the denso sensor cable -- after that the engine light came on and I could not put the rev above 2500. With that plugged in, it's easy to get up to 4000 (albeit sluggish)

2) to disconnect the the MAF sensor cable -- it seems that it makes no difference. Note the engine light did NOT come on. I even took the car for a spin but no change in behaviour.. so can we exclude the MAF failure or it's not an exhaustive test, either? The link
viewtopic.php?f=1&t=16744&p=164639&hilit=maf#p165586
says if things improve or stay the same then this component is faulty?! I would definitely agree, if things had improved but not really sure, since I witnessed no change? Would replacing the MAF resolve dead spots only or would it apply to my case, too?


Welly.. thanks very much for your input.. I think I'll discuss them first with the mechanic to see what they ticked off.. and then I might look for a specialist..

Thanks...

[lozz]

Dosent the turbo solenoid and egr solenoid get its vac from The servo?

iirc on the old d9 ihad - it had a scabby looking pipe that went into a T-peice which plugged in the servo,
irember putting new pipe on it because it looked perished,

[lozz]

Here look

http://www.fixya.com/cars/t2697533-turb ... 6_hdi_2000


blocked vacume pipe where it conects to servo



For the ecu to cut fuel, it wouid have to sense, overboost, (or am i miles out idunno )

so if perhaps you mech as modified /bypassed pipes, the ecu is sensing overboost,

iwouidnt condemn the ecu id be looking at other things perhaps the actuator,

[OdinEidolon]

This is definitely a vacuum problem, tell them to check all vacuum tubes, the swirl valve, swirl diaphragm, all electrovalves, swap them (they should be the same P/N) and check the funztion with a vacuum probe. See the excellent guide on how to solve vacuum problems on the 2.2HDi (similar) from exboyracer on the 406 coupé UK forums.

[Doggy]

This is definitely a vacuum problem, tell them to check all vacuum tubes, the swirl valve, swirl diaphragm, all electrovalves, swap them (they should be the same P/N) and check the funztion with a vacuum probe. See the excellent guide on how to solve vacuum problems on the 2.2HDi (similar) from exboyracer on the 406 coupé UK forums.

I agree with Adriano, this is probably a vacuum problem, (but your 110 HDi does not have a swirl valve or actuator).

Exboyracer's guide and subsequent observations is the definitive source of wisdom for vacuum issues.

[OdinEidolon]

This is definitely a vacuum problem, tell them to check all vacuum tubes, the swirl valve, swirl diaphragm, all electrovalves, swap them (they should be the same P/N) and check the funztion with a vacuum probe. See the excellent guide on how to solve vacuum problems on the 2.2HDi (similar) from exboyracer on the 406 coupé UK forums.

I agree with Adriano, this is probably a vacuum problem, (but your 110 HDi does not have a swirl valve or actuator).

Exboyracer's guide and subsequent observations is the definitive source of wisdom for vacuum issues.

Ops sorry, I just listed the standard sentence given as a response for this kind of problems
Thanks Eric.

[Busman]

This does sound so much like the symptoms I got when my MAF went wrong. Fixed for £37 from ebay.

[seasonshu]

Thanks Busman for the reply.
Before I bumped this thread I wanted to read exracerboys article (for the record: http://www.406coupeclub.org/PHPBB3/view ... 0&p=370222)

I actually asked about the MAF, although the mechanic said they checked that, according to the descriptions it seems that the only way to be sure is to replace it?

The follow-up I wrote two days ago was:

"Ok guys, I talked to Ian the mechanic.

He showed me that the initial vacuum is present in the pipe coming from the brake. The plug has two wires going into the Turbo Wastegate Solenoid/Electrovalves (pictured above) and both show voltage of 3.63V against ground.
He thinks that either the command (i.e. change of voltage) does not come from the ECU or the solenoid does not pull in -- but he cannot measure magnetism. So suggested to replace the two solenoids (anyway, why are there two?). He mentioned that he swapped the two solenoids (both can't be wrong) and according to him the situation got better (although I haven't noticed anything while driving).

I checked the voltages in both pins again at home to see if either of them changes when the rev is going up to 3000rpm. Unfortunately there is no change, both pins show constant 3.63V... I am still wondering if the ECU is wrong -- should it give command when the vehicle is stationery or since many other inputs will be calculated in I can't replicate on the driveway.

Anyway, I also showed him the long list of possible failures you suggested and he said they've been all through of them. There is an oil patch at the bottom of the intercooler; however he mentioned that he took the pipe off, sprayed WD-40 in the pipe and if there was a leak, the liquid would have spurt out. I asked about the MAF sensor and it's also been checked.

Honestly speaking I got around to show the list from Odin but not from Welly; that seems lees likely to contain the cause (pump is working -- there is vacuum in the initial pipe; vacuum leak -- should have been checked; throttle processor sensor -- I don't know what that is but no engine sign is on; boost sensor: is this the denso sensor? -- when pulled off the rev won't over 2500rpm, otherwise can go up to 4000rpm).
"

Do you still think that it can be the MAF? I was not convinced that he really checked it and if he can really check it without replacing it! I am not sure if the measured voltage behaviour gets us any further or not really useful information? Thanks.

[lozz]

some stuff from Hj. might be worth a read

http://www.honestjohn.co.uk/forum/post/ ... tm?t=68900

[seasonshu]

some stuff from Hj. might be worth a read

http://www.honestjohn.co.uk/forum/post/ ... tm?t=68900

Thanks lozz..
I found that the referred post mentioned that 12v should appear for the first few seconds the ignition is turned on -- I thought it talked about the solenoid and turned out to be the HP pump (I don't where that is ).

Anyway: athe yellow cable showed around 3.3V which crawled up to 3.6V... the purple cable showed 3V for some seconds and crawled up to 3.6V again... is it any informative?

The cure in the referred thread was to clean the MAF sensor.. So probably that should be my next move..? I read it in many threads that it should be cleaned with care -- what does that actually mean? Should I spray WD40 into it without touching 'anything'? Can I just unscrew it? -- I am afraid of breaking something that is airtight and cannot replace the same way. I already tried unplugging the MAF wire -- no change

Would there be any use of (soft) resetting the ecu? Can I do it without taking it for a reprogramming? If so what's the easiest way? Just remove the negative cable from the battery for half an hour? That is, only if the above voltage readings show anything out of ordinary?

Only if I knew what needs to be changed.. but changing parts until it's good does not sound tempting..

[Welly]

Why not try looking at the following diagnostic Forum too........http://www.ilexa.co.uk/

Looks like the 'Forum' bit is down for maintenance but there's always been good info available on there. You could register and post up a new thread asking for advice.