Intermittent limp mode

[jasbha]

Thanks. Makes sense to me now having seen a sensor fixed to the outlet on the right hand side of the intercooler (when facing the car).

The haynes manual (yeah, I know....) mentions dropping the intercooler/radiator out the underside of the car whereas I've seen others say its better to remove the bumber/slam panel.

I'd appreciate any views on the best way forward.

[T5RatherAmusin]

ye, you can. i went with slam panel off, but i was doing alot of show speccing work on the car.....
all it would be its to unbolt the slam panel, put it out the way, undo the rad pack bolts( maybe even the 2 under rad mount bolts to get more room to remove the intercooler) seprate the pack and pull out the intercooler- obv undoing boost pipes

[jasbha]

ye, you can. i went with slam panel off, but i was doing alot of show speccing work on the car.....
all it would be its to unbolt the slam panel, put it out the way, undo the rad pack bolts( maybe even the 2 under rad mount bolts to get more room to remove the intercooler) seprate the pack and pull out the intercooler- obv undoing boost pipes

Many thanks. Reckon I'll try dropping it out below as I don't fancy having loose bumpers after removing them. Could probably benefit from changing the coolant and flushing it through anyway

[LeeT5]

You don't need to drop the coolant but it's easy to do, so u may as well do it. Get a new expansion bottle too. They have been modified slightly so the p/s reservoir no longer fouls the ecu cover.
You can drop it out the bottom or the top, which ever works for you at the time. Recommend a second pair of hands thou at the removal stage to minimise damage to the aircon condenser and radiator fins.
I advise you drop the coolant as it makes the rad pack lighter and easier to work with.

[jasbha]

Hi, I changed the intercooler without too much of a problem. Despite the intercooler having a number of leaks the intermittent fault remained when not fully up to temperature so I targetted the EGR. I removed the EGR and sheared a bolt when taking it apart from the cooling manifold but managed to drill through the bolt and put a smaller bolt through with a nut on the end - a bit of a pain and a bit of a bodge really. Irritating as the valve and cooler seemed pretty clear anyway.

After putting it all together it's far worse then before, absolutely no turbo pressure at all. I called the AA out and he spent a bit of time with the car and said the hoses were sucking in when they should have been flexing out and felt sure the turbo had gone. You can't hear the turbo operating either.

I don't believe on coincidences so was wondering whether anyone could advise if there was anything I could have done/left unplugged (?) when removing/re-fitting the EGR? The AA guy said that regardless of sensors etc the turbo should spin anyway when the engine is revved up and hence was pretty certain that it had failed. Would my messing about with the EGR lead to the turbo failing to generate pressure?

The following codes were read by the AA guy but I would have thought that most were associated with me removing and re-fitting the EGR:

P0102 MAF sensor
P0108 MAP sensor
P0112 Intake air temp sensor
P0244 turbo charger wastegate solenoid
P0489 exhaust gas recirculation control circuit low

Any help would be greatly appreciated. Also, does anyone know of anywhere in Kingston on Thames area that I could get a good price for a turbo replacement if it is shot? Or does anyone fancy a very sluggish car??!!!

[LeeT5]

Hi, I changed the intercooler without too much of a problem. Despite the intercooler having a number of leaks the intermittent fault remained when not fully up to temperature so I targetted the EGR. I removed the EGR and sheared a bolt when taking it apart from the cooling manifold but managed to drill through the bolt and put a smaller bolt through with a nut on the end - a bit of a pain and a bit of a bodge really. Irritating as the valve and cooler seemed pretty clear anyway.

After putting it all together it's far worse then before, absolutely no turbo pressure at all. I called the AA out and he spent a bit of time with the car and said the hoses were sucking in when they should have been flexing out and felt sure the turbo had gone. You can't hear the turbo operating either.

I don't believe on coincidences so was wondering whether anyone could advise if there was anything I could have done/left unplugged (?) when removing/re-fitting the EGR? The AA guy said that regardless of sensors etc the turbo should spin anyway when the engine is revved up and hence was pretty certain that it had failed. Would my messing about with the EGR lead to the turbo failing to generate pressure?

The following codes were read by the AA guy but I would have thought that most were associated with me removing and re-fitting the EGR:

P0102 MAF sensor Air leak
P0108 MAP sensor
P0112 Intake air temp sensor I believe this is also your Boost pressure sensor - and may be leaking air due to not seated correctly
P0244 turbo charger wastegate solenoid Air leak
P0489 exhaust gas recirculation control circuit low Possible Air leak

Any help would be greatly appreciated. Also, does anyone know of anywhere in Kingston on Thames area that I could get a good price for a turbo replacement if it is shot? Or does anyone fancy a very sluggish car??!!!

In a word, No!

If the turbo was working before and you've only replaced the IC and now mucked about with the EGR, then the turbo has not just suddenly stopped working.
You've either induced an airleak by not securing a pipe, Jubilee clamp, vac hose or sensor not screwed down tight or a pipe/hose has split.

If you do not want to go through every component that you've touched and hopefully see the problem with your eyes then you really only have one option. Find a local garage that can do a 'smoke leak test'.
I guarantee you when you have this done it will find lots of leaks! Then it's a case of fixing those leaks, which may just mean tightening a clamp or replacing a split bit of vac hose.
Until then, your guessing or pissing in the wind.

Also, a faulty EGR valve or one that is stuck closed, will cause sluggish performance and no boost.

As for not believing in coincidences......you should!
Quote: "After putting it all together it's far worse then before, absolutely no turbo pressure at all." <<<<<<< That to me is a coincidence.

[jasbha]

In a word, No!

If the turbo was working before and you've only replaced the IC and now mucked about with the EGR, then the turbo has not just suddenly stopped working.
You've either induced an airleak by not securing a pipe, Jubilee clamp, vac hose or sensor not screwed down tight or a pipe/hose has split.

If you do not want to go through every component that you've touched and hopefully see the problem with your eyes then you really only have one option. Find a local garage that can do a 'smoke leak test'.
I guarantee you when you have this done it will find lots of leaks! Then it's a case of fixing those leaks, which may just mean tightening a clamp or replacing a split bit of vac hose.
Until then, your guessing or pissing in the wind.

Also, a faulty EGR valve or one that is stuck closed, will cause sluggish performance and no boost.

As for not believing in coincidences......you should!
Quote: "After putting it all together it's far worse then before, absolutely no turbo pressure at all." <<<<<<< That to me is a coincidence.

Thanks for the response. My comment about coincidences was that I felt the problem must be something to do with what I'd done rather than the turbo suddenly deciding to give up.

I'll go through the checks you suggest. The one thing I don't understand though is why a leak on the suction side of the turbo would lead to a loss of pressure to the engine. Wouldn't this just result in air being drawn in from elsewhere to serve the engine and wouldn't you be able to hear it? The only work on the discharge side of the turbo was the intercooler (and this problem didn't exist after that) and the connection of the EGR cooler to the engine intake pipe, which seems really secure.

[LeeT5]

The one thing I don't understand though is why a leak on the suction side of the turbo would lead to a loss of pressure to the engine. Wouldn't this just result in air being drawn in from elsewhere to serve the engine and wouldn't you be able to hear it? The only work on the discharge side of the turbo was the intercooler (and this problem didn't exist after that) and the connection of the EGR cooler to the engine intake pipe, which seems really secure.

Any air leak 'post' MAF is unmetered air and air that the ECU is not expecting to see. Therefore, the ECU will try to adjust trim to suit. This may imply reduced boost by way of controlling boost pressure via the TCV.
I am not fully conversant with the intercooler hose routing and various vac hoses on a D5 but they can't be too dissimilar to an R-line petrol or T5 model. Only obvious difference is the D5 has a EGR whereas the T5/R doesn't.
I can tell you now after I recently replacing both my IC and PCV system, I've just had 2 months of stressful, time consuming and pain staking fault diagnosis and investigative work done on my car. I had to have a smoke leak test because if i didn't, I would never have known that the MAF to TURBO pipe was leaking or the new 'red hose' from TCV to TURBO was split at the turbo. There was also two other leaks but that's for another thread.
I had 3 or 4 intermittent faults codes that kept appearing after they were cleared as well as intermittent poor idle, no boost, over-boost, Limp mode, hesitation under medium throttle, surging.....you name it, I had it!

The common denominator in this is YOU! The car, I'm assuming was driving ok before you changed the IC? Therefore, if it is still not right and the IC was definitely cracked, then there is something you've missed. Like I said, from experience, you could spend many, many man hours trying to work out what's not tight or fitted properly and waste time going over everything you've touched only to find it's a loose Jubilee on the IC pipe or something like that. Best advice is to get the car smoke leak tested (Dealers can do this for you) and go from there.
You'll be surprised just how much has to be disconnected when replacing an IC. All the connections that cause air leaks would include:- MAF > TURBO, TURBO > IC, IC > ETM, Manifold vac lines, EGR pipework, BPS.

One thing I will say is, just because a Jubilee clamp is tight does not mean it doesn't leak! As I recently found out. This is the reason why a smoke leak test will be a conclusive way of diagnosing any external leaks. It will not expose internal leaks ie Purge valves.

[jasbha]

Any air leak 'post' MAF is unmetered air and air that the ECU is not expecting to see. Therefore, the ECU will try to adjust trim to suit. This may imply reduced boost by way of controlling boost pressure via the TCV.
I am not fully conversant with the intercooler hose routing and various vac hoses on a D5 but they can't be too dissimilar to an R-line petrol or T5 model. Only obvious difference is the D5 has a EGR whereas the T5/R doesn't.
I can tell you now after I recently replacing both my IC and PCV system, I've just had 2 months of stressful, time consuming and pain staking fault diagnosis and investigative work done on my car. I had to have a smoke leak test because if i didn't, I would never have known that the MAF to TURBO pipe was leaking or the new 'red hose' from TCV to TURBO was split at the turbo. There was also two other leaks but that's for another thread.
I had 3 or 4 intermittent faults codes that kept appearing after they were cleared as well as intermittent poor idle, no boost, over-boost, Limp mode, hesitation under medium throttle, surging.....you name it, I had it!

The common denominator in this is YOU! The car, I'm assuming was driving ok before you changed the IC? Therefore, if it is still not right and the IC was definitely cracked, then there is something you've missed. Like I said, from experience, you could spend many, many man hours trying to work out what's not tight or fitted properly and waste time going over everything you've touched only to find it's a loose Jubilee on the IC pipe or something like that. Best advice is to get the car smoke leak tested (Dealers can do this for you) and go from there.
You'll be surprised just how much has to be disconnected when replacing an IC. All the connections that cause air leaks would include:- MAF > TURBO, TURBO > IC, IC > ETM, Manifold vac lines, EGR pipework, BPS.

Many thanks for taking the time to respond. I've gone back over the work I did yesterday and found a vacuum hose broken at the connection to a tee piece. I've cut it back and re-connected it and it's back to how it was. I'm absolutely amazed that such a small pipe could have such a huge difference.

However, I've still got the problem of the intermittent fault when not fully warmed up, which was the problem I had initially. So far I've ruled out EGR, intercooler and engine mounts so I'm going to try to use my AA insurance to get the top half of the engine cleaned out (if my garage is happy to identify that as the fault).

Thanks again for the responses, it's much appreciated. just relieved that I haven't knackered the turbo through fiddling about as that would have been (was!) an extremely depressing thought.

[LeeT5]

Many thanks for taking the time to respond. I've gone back over the work I did yesterday and found a vacuum hose broken at the connection to a tee piece. I've cut it back and re-connected it and it's back to how it was. I'm absolutely amazed that such a small pipe could have such a huge difference.

However, I've still got the problem of the intermittent fault when not fully warmed up, which was the problem I had initially. So far I've ruled out EGR, intercooler and engine mounts so I'm going to try to use my AA insurance to get the top half of the engine cleaned out (if my garage is happy to identify that as the fault).

Thanks again for the responses, it's much appreciated. just relieved that I haven't knackered the turbo through fiddling about as that would have been (was!) an extremely depressing thought.

That would explain the loss of power and boost.

I'm guessing that the 'T' hose comes from the manifold and connects to the back of the CBV on the Turbo. The reason you had no boost is because under boost the vac line would be pressurized and keeping the CBV closed. Due to the split pipe, although the Manifold was pressurized to a degree, you would have been losing loads of pressure through that split and there would have been no pressure to act on the rear of the CBV. So, whatever you CBV's spring pressure is rated at, this is what it would have opened at and that would have meant hardly any boost at all along with a probable TCV fault code for 'signal too high'.

You'll need to make sure you reset the car's ECU otherwise it will still be adapting and with that fault code logged, it won't do you any favours. Just disconnect the battery for 5 minutes.
Make sure you cycle the locks before you restart otherwise you'll induce an alarm fault and store a code.

[jasbha]

That would explain the loss of power and boost.

I'm guessing that the 'T' hose comes from the manifold and connects to the back of the CBV on the Turbo. The reason you had no boost is because under boost the vac line would be pressurized and keeping the CBV closed. Due to the split pipe, although the Manifold was pressurized to a degree, you would have been losing loads of pressure through that split and there would have been no pressure to act on the rear of the CBV. So, whatever you CBV's spring pressure is rated at, this is what it would have opened at and that would have meant hardly any boost at all along with a probable TCV fault code for 'signal too high'.

You'll need to make sure you reset the car's ECU otherwise it will still be adapting and with that fault code logged, it won't do you any favours. Just disconnect the battery for 5 minutes.
Make sure you cycle the locks before you restart otherwise you'll induce an alarm fault and store a code.

Yes, that was the T-hose that was affected. thanks for the explanation, that makes a lot more sense to me now.

So are you saying that because the ECU has faults logged it will tend to see these faults and highlight errors in future even if the issue has been resolved? I'm wondering whether that is the reason that my intermittent fault continued after replacing the intercooler.

[LeeT5]

Whatever happens, you need to clear codes mate. Don't leave them in the cars ECU. It will read them on every reboot when it starts. If they are severe enough, the ECU may adapt to make things 'SAFE'. Therefore, you'll have no boost.

Clear codes every time you fix a fault. Otherwise, you'll not know if you've fixed the problem or revealed/made any new ones!!

[M-R-P]

Just to add...

Key in position II when reconnecting the battery - there have been stories of all the airbags deploying...

[cherry1809]

Sounds like the same as mines doing. I checked all the usual culprits and found that when I cleaned out the TCV, it was better. Usually lasts a few months before it needs doing again. Only takes half hour and doesn't cost anything.
All I do is spray a load of carb cleaner down it which usually runs out black.

[jasbha]

Just to add...

Key in position II when reconnecting the battery - there have been stories of all the airbags deploying...

Thanks - the airbags going off would just about finish me off I reckon!

[jasbha]

Sounds like the same as mines doing. I checked all the usual culprits and found that when I cleaned out the TCV, it was better. Usually lasts a few months before it needs doing again. Only takes half hour and doesn't cost anything.
All I do is spray a load of carb cleaner down it which usually runs out black.

Excuse my ignorance but where is the TCV (is this the throttle control valve or turbo control valve)?

If Turbo control valve is this the tiny plastic box to the side of the air cleaner?

[cherry1809]

Turbo control valve. If you take off the small black intake hose on the front of the engine, it's behind that bolted to the block. Has a plug and 3 small vac pipes going to it
That's what was giving me the P0244 code

EDIT: Might only be 2 pipes... it's me age

[jasbha]

Turbo control valve. If you take off the small black intake hose on the front of the engine, it's behind that bolted to the block. Has a plug and 3 small vac pipes going to it
That's what was giving me the P0244 code

EDIT: Might only be 2 pipes... it's me age

Thanks - I think I know the one. I'll give it a try

[M-R-P]

Thanks - the airbags going off would just about finish me off I reckon!

2 X 5 foot curtain airbags
2 X 2-stage front airbags (dash and steering wheel)
2 X Seat bolster airbags
2 X front seatbelt pretensioners

All of these deploying at once will pretty much destroy the interior and write the car off

[mikerd4]

We had similar with my wifes V50 D2. Volvo had the car a fortnight and in the end claimed it was water in the diesel, they replaced the fuel filter and we havent had the same issue again (Im also more careful where I buy Diesel from now). They could have done anything without telling me as it was a warranty job but the filter is what they blamed