1.9 Transporter loosing power

hasha

Hi All,
I have a 04 T5 1.9 turbo diesel with inter-cooler. It has been loosing power recently. I brought it to a local guy who tested it and said it might be the map sensor, which I replaced with a VW part. Also changed the diesel filter, but no improvement. Checked all the intercooler pipes, going around the front of the engine, they seem to be ok. When driving with a cold engine in the morning, it's ok. But when driving home, along the motorway I can feel the engine loosing power almost instantaneously,like a switch was turned, when I press the accelerator there is no response. If I switch the engine off for a few secs and free wheel, when I switch the engine back on the power returns for a while.
Not sure if this is related, but sometimes when I start the engine first thing in the morning, it revs a bit on it's own for ten seconds or so.
Would really appreciate any advice or suggestions to sort this out,
cheers
hasha

bigroad

possible injector fault.did you get a diagnostic done.

tossy

Sounds like sticking veins on the turbo,bring it to someone who knows what they are at for a proper diagnosis.

hasha

possible injector fault.did you get a diagnostic done. yeah had a diagnostic done, I think he said it was over pressurizing, and to replace the map sensor, didn't make any difference!

bigroad

hasha wrote: »

possible injector fault.did you get a diagnostic done. yeah had a diagnostic done, I think he said it was over pressurizing, and to replace the map sensor, didn't make any difference!

George Dalton is the expert on them ,he is on here or will be along shortly.Best not to buy any more parts till you know exactly whats wrong.The injectors are pricey for those pump duse tdi s .Im not sure but there could be a fuel pressure sensor or regulator on those aswell.
But i think the injectors do most of the work.

pburns

bigroad wrote: »

George Dalton is the expert on them ,he is on here or will be along shortly.

He's probably at the EP like any self-respecting Laois hipster! It's a bugger when you are spending money & not getting to the root of the problem - I've been there...

Mar4ix

if that would be faulty injector , it wouldnt work from cold either, it would misfiring and shake van as hell, hard to say whats wrong , but would suspect temperature sensor ?? it is easy to check, if it stuck in cold , resistance have to be high something 10 k ohms, hot or cold(i think on hot have to be 0.2 k ohms) , if you have tester you could check.

My friend was fixing his car with George, very happy and reasonably priced.

hasha

Mar4ix wrote: »

if that would be faulty injector , it wouldnt work from cold either, it would misfiring and shake van as hell, hard to say whats wrong , but would suspect temperature sensor ?? it is easy to check, if it stuck in cold , resistance have to be high something 10 k ohms, hot or cold(i think on hot have to be 0.2 k ohms) , if you have tester you could check.

My friend was fixing his car with George, very happy and reasonably priced.

yeah there is no shaking from engine at all, it just seems to loose power when the engine has gotten hot and it happens almost instantaneously, maybe as you say it is the temperature sensor, unfortunately I haven't got a tester

Mar4ix

hasha wrote: »

yeah there is no shaking from engine at all, it just seems to loose power when the engine has gotten hot and it happens almost instantaneously, maybe as you say it is the temperature sensor, unfortunately I haven't got a tester

If do diagnostics, it should show what temperature sees ecu, if i am not mistaken, depend of temperature, ecu changes timing, or something, which affects engine performance, if you around blanchardstowm could have a look ... i have original vag-com.

hasha

Mar4ix wrote: »

If do diagnostics, it should show what temperature sees ecu, if i am not mistaken, depend of temperature, ecu changes timing, or something, which affects engine performance, if you around blanchardstowm could have a look ... i have original vag-com.

Thanks, appreciate the offer, if I don't have have any look locally I might take u up on it.
Maybe a dodgy temperature explains why it revs out by itself when I start it in the morning?

Mar4ix

hasha wrote: »

Thanks, appreciate the offer, if I don't have have any look locally I might take u up on it.
Maybe a dodgy temperature explains why it revs out by itself when I start it in the morning?

it is normal, if engine is cold, revs are over 1k rpms, it drops after a min, and when well warm, it goes down as should be., same with petrol cars, revs always first few min are over 1 or even 1.5 k , if it goes over 2 k, so we would suspect other problems , like throttle position sensor or so.

hasha

Mar4ix wrote: »

it is normal, if engine is cold, revs are over 1k rpms, it drops after a min, and when well warm, it goes down as should be., same with petrol cars, revs always first few min are over 1 or even 1.5 k , if it goes over 2 k, so we would suspect other problems , like throttle position sensor or so.

yeah u are correct, it only happens just after starting, not during the day. U seem to know your stuff.
If the temperature sensor is dodgy, would the ecu reset itself when I switch the engine off, because the power returns after doing this

Mar4ix

hasha wrote: »

yeah u are correct, it only happens just after starting, not during the day. U seem to know your stuff.
If the temperature sensor is dodgy, would the ecu reset itself when I switch the engine off, because the power returns after doing this

No, then it is not temp sensor, I thought there is no power all day, when engine is warm. in your case could be turbo pressure sensor ... i know in passat it is located behind engine on air pipe, which is pretty common problem.
also blocked exhaust or catalytic converter indicates lack of power... at least i've seen this on petrol engines.

in reality, have to connect to diagnostics, and see what we get, not only fault codes, but also need read data from working engine, and see if sensors working within limits.
I am not pro, but just learning... now is good while i am doing this.

George Dalton

I assume that by "over-pressurising" he meant over-boosting.

The fact that it only happens when the engine is hot does point to an issue with the VNT mechanism inside the turbo. Other causes of over-boost would happen all the time, but the VNT can sometimes be ok when cold but get sticky when hot.

Mar4ix

George Dalton wrote: »

I assume that by "over-pressurising" he meant over-boosting.

The fact that it only happens when the engine is hot does point to an issue with the VNT mechanism inside the turbo. Other causes of over-boost would happen all the time, but the VNT can sometimes be ok when cold but get sticky when hot.

OP - Thats the man who knows the stuff, youll get sorted.

that turbo boost sensor is same name called as map sensor, so you have changed with original new one, and no change, which indicates that the problem is somwhere else or faulty wiring, what i've found out in internet.

Mar4ix

Georg, op says power is back for short while after he switch off and switch on engine , even when it is in working temperature. would that VNT somehow unstick by doing that ?

George Dalton

Mar4ix wrote: »

Georg, op says power is back for short while after he switch off and switch on engine , even when it is in working temperature. would that VNT somehow unstick by doing that ?

After the ECU recognises the over-boost condition it logs the fault code and goes into limp mode, hence the lack of power. Cycling the ignition resets the ECU and it resumes normal operation until the next time the over-boost happens.

Obviously all of this is guesswork without seeing the van, but the symptoms do seem to fit.

dieselbug

hasha wrote: »

possible injector fault.did you get a diagnostic done. yeah had a diagnostic done, I think he said it was over pressurizing, and to replace the map sensor, didn't make any difference!

Over pressurizing wont bear any relationship to injectors or temp sensor.

Vnt will be a likely suspect though, a little testing in the right hands will soon tell;)

hasha

George Dalton wrote: »

After the ECU recognises the over-boost condition it logs the fault code and goes into limp mode, hence the lack of power. Cycling the ignition resets the ECU and it resumes normal operation until the next time the over-boost happens.

Obviously all of this is guesswork without seeing the van, but the symptoms do seem to fit.

Thanks for the advice, seems to be getting near the root of the problem.
From the myturbodiesel site he suggests spraying lubricating spray around the vnt lever and also after the engine has warmed up to drive engine hard for a while to to clear out any soot?

hasha

hasha wrote: »

Thanks for the advice, seems to be getting near the root of the problem.
From the myturbodiesel site he suggests spraying lubricating spray around the vnt lever and also after the engine has warmed up to drive engine hard for a while to to clear out any soot?

This was just general advice for diesel engines, not specific to my van