Limp Mode - help please!

[badger1777]

Hello to this excellent forum, where I've found lots of tips in the past.

I've got a problem with the turbo on my Cali.... Whenever I'm going at speed and up hill, my Cali keeps cutting into limp mode and the warning light comes on.

I've taken it to a VW engineer I know who did a diagnostic and said it is soot build up in the turbo system (vanes sticking) and tried to sort it by changing some settings and thrashing the engine to blast out any deposits, but to no avail. I didn't take it any further as he told me how expensive a new turbo could be....

Anyway, the problem keeps happening. Can anyone give me some advice please?! I'm interested to know if anyone recognises these symptoms, or any advice on sourcing a turbo more cheaply than VW will charge me, or whether a turbo clean kit really works, etc. All advice gratefully received!

Thanks

 

[Barefoot62]

Have you checked for oil leaks around the turbo? This could cause carbon build up sticking to the oily deposits and causing a build up of pressure in the turbo the sensor will then trip out and put the engine into limp mode. Hope this helps. As far as getting a cheaper turbo I would defiantly go for a genuine VW part then you know your covered

Alasdair

 

[Iron Van]

I had a problem with my T5 recently. One evening it went into limp mode, I pulled over and turned the engine off and then back on again and it seemed to reset itself.

The following morning on the road to Heathrow it did the same, this time I limped to the car park. I called the local dealer and he explained it was probably soot and that I could try something like Redex and rev a bit higher for a couple of trips to see if it would sort it out.

When I got back, I filled up and emptied the whole bottle of Redex into the tank and drove 2 hours home at higher than normal revs including holding it high a couple of times from lights etc.

Not sure if I was lucky not to do some damage or if it was the right thing to do, but for me it seems to have worked and I haven't had a repeat of the problem.

Cheers

Steve

 

[Alan]

Hi Steve,

That's a bit concerning for a 2014 model (your details on bottom of your post)...
Do you drive on regular short journeys,how many miles has your bus done ?
I would be interested to know.

Cheers,
Alan

 

[Goldie]

Steve,

That does sound a bit concerning given you live in the Ross area and were driving to Heathrow e.g. 100 miles plus each way. I often drive in the opposite direction from Northwood to Garway and the road is reasonably open and a good run so I can't see why it would soot up. Redex sounds a bit drastic for such a new vehicle.

Andy

 

[Stu]

For the OP I think your diagnosis is likely to be correct, it certainly is the symptoms of sticking VNT Vanes.

You don't say which engine you have.

Although this picture is tagged Volvo it's the same principle -



You will see that there is an actuator which uses vacuum to move the variable geometry vanes inside the turbo casing and this has the effect of being able to dynamically adjust the pressure produced by the turbo according to the needs of the engine load. What happens is that these vanes become clogged with sooty deposits and stick, often in the maximum position which causes an overboost which is then sensed by the ECU and results in the ECU adopting the safe 'limp mode'.

There are a huge number of resources around the web that will tell you how to clean the turbo, most of which involve removing it to strip and clean it. I think there are also some acid based chemicals which can also be used with the turbo in situ although I don't know so much about the success rate and I am cautious of the long term effects of bearing seal damage caused by the chemical process.

So the No 1 solution is a replacement Turbo either a recon or genuine part depending on cost, either way all will be on an exchange basis. You will also need some gaskets etc and to factor in labour if not doing it yourself. I would suspect Circa £1k.

You may think the chemical solution worth a try as you have little to lose, depends on the cost I guess.

 

[Iron Van]

Sorry guys, I should have made it clear. This didn't happen to my new Beach, it happened to my 2008 T5 174.

I work away, so most of the time the T5 sits outside the house and normally only gets used by my wife once a week or so to run my daughter to school (doesn't even get hot but keeps the battery topped up).

With the recent bad weather and issues with public transport I decided to drive to Heathrow and leave the truck in the car park whilst away. But like I said, since I put the Redex in I haven't had any further issues....touch wood.

 

[badger1777]

Thankyou all for your help.

Alasdair, thanks for the idea about oily deposits - I'll get that checked. Stu thankyou for the detailed information... your thought of what we need to do is pretty much what I've concluded.

I'm looking into an chemical cleaning kit but I just don't know if i'm that comfortable with it - I'll see what I can find out. It's a shame these turbos are so susceptible over short distances.

If anyone has experience of the chemical cleaning kits, please let me know your thoughts.

Cheers

 

[bvddobb]

If anyone has experience of the chemical cleaning kits, please let me know your thoughts.

We don't have any such experience ourselves, but we have seen it advised on many forums. Twice a year, drive relatively high-rev with it in the tank for some time, and it seems it keeps everything (turbo, DPF, Catlyst) clean...

 

[Stu]

I googled and found this stuff

Turbo Clean Set

Available on eBay for around £35

 

[briwy]

Have you been using cheap supermarket fuel?
I was talking to a guy who worked for an oil company about this when we had exactly the same problem on the Mazda Bongo we had and he said that whilst all fuel sold here has to meet minimum standards the more expensive branded fuels do have various additives (possibly similar to the Redex additive) which help to reduce this sooting up. We had been filling up with cheap fuel and as soon as we filled up with branded stuff the problem stopped.

 

[Stu]

Have you been using cheap supermarket fuel?
I was talking to a guy who worked for an oil company about this when we had exactly the same problem on the Mazda Bongo we had and he said that whilst all fuel sold here has to meet minimum standards the more expensive branded fuels do have various additives (possibly similar to the Redex additive) which help to reduce this sooting up. We had been filling up with cheap fuel and as soon as we filled up with branded stuff the problem stopped.

:lol:



Now you've started something!!

 

[badger1777]

Thanks guys.

Stu, thanks for the link. I'm checking that against this one I found yesterday: http://www.dieselturbocleaner.co.uk/

briwy, interesting point about the fuel, I've heard something about that before. I can't say it's that though, I just fill up wherever I can, a mix of brands and rarely supermarket.

Cheers

 

[robo]

I have noticed an oil temperature readout on the computer. I have often looked at it, and its very interesting, but why is it there?. I have checked the manual but cannot work out what its for. Would oil temperature be anything to do with turbo performance?

 

[Stu]

Oil temperature is the indication that your engine is at operating temperature or not, and not the water temp as most think.

 

[badger1777]

Oh dear, I've now got an electrical fault of some sort.

The central control unit is not working unless the engine is running, at which point the clock has to be reset. Suggests power / battery issue, maybe fuse. I'm also getting a strange fault message - 'Voltage Plausibility Fault'...

Also the main trip switch in rear storage area was tripped when I checked, so I flipped the switch back to on, and tried the test button which didn't do anything, so something's not right. Im doing a 230 mile drive this evening, so i'll see if the unit is working once the engine has charged the batteries.

Can't find this fault listed in any of the manuals

Any thoughts?

 

[Stu]

viewtopic.php?f=21&t=5980

 

[badger1777]

Thanks Stu...

I'm not a happy bunny! But at least it's friday

 

[TH Performance]

Hello to this excellent forum, where I've found lots of tips in the past.

I've got a problem with the turbo on my Cali.... Whenever I'm going at speed and up hill, my Cali keeps cutting into limp mode and the warning light comes on.

I've taken it to a VW engineer I know who did a diagnostic and said it is soot build up in the turbo system (vanes sticking) and tried to sort it by changing some settings and thrashing the engine to blast out any deposits, but to no avail. I didn't take it any further as he told me how expensive a new turbo could be....

Anyway, the problem keeps happening. Can anyone give me some advice please?! I'm interested to know if anyone recognises these symptoms, or any advice on sourcing a turbo more cheaply than VW will charge me, or whether a turbo clean kit really works, etc. All advice gratefully received!

Thanks

Did you get any fault codes? The van goes into limp mode therefore the ecu should have logged the fault code for why. He mentioned soot, did he mention anything about the dpf? It could be a number of things and it would be a lot easier to diagnose with some fault codes to start with. We've seen this happen and it's been caused by loose pipes (2.5's are notorious with their pipes swelling thus causing a loss of pressure etc) on quite a few occasions.

 

[badger1777]

Did you get any fault codes? The van goes into limp mode therefore the ecu should have logged the fault code for why. He mentioned soot, did he mention anything about the dpf? It could be a number of things and it would be a lot easier to diagnose with some fault codes to start with. We've seen this happen and it's been caused by loose pipes (2.5's are notorious with their pipes swelling thus causing a loss of pressure etc) on quite a few occasions.

Hi, yes, we did talk about the dpf but I can't remember the details and he did get the error codes, but I don't have them. The main thing I remember was discussing the vanes getting stuck. You're comment makes me think that this could be more complicated. If there is a problem with the dpf, can this be remedied or do they have to be replaced?

 

[TH Performance]

Choices are forced regeneration if it is still below the threshold, replacement of the dpf (not cheap) or something called dpf delete which involves removing the insides of the dpf and re-calibrating the ecu.

You can check how full the dpf is using vagcom.

Regards

Terry

 

[badger1777]

Thanks for the info. I think the forced regeneration is what was tried already, the engineer changed some settings on the ecu and drove the van hard for a period. Didn't work... I'm assuming that a dpf problem will just re-clog the vanes on a cleaned turbo?? ie. - cleaning turbo no use if dpf compromised.

 

[TH Performance]

A blocked DPF will result in vehicle going into limp mode as it can't breather properly.

Other problems, heats up too much as it's saturated, cracked manifold heads, we've even had an exhaust and turbo start melting.

If you are anywhere near Fareham in Hampshire we would be more than happy to look at this free of charge and give you that second opinion.

 

[smgcowfoldparts]

A blocked DPF more than likely will not reset itself by turning the engine on and off. You would also probably have two to three warning lights on the dash alerting to you that there is a problem. Your described issue sounds very much like a turbo not DPF issue. If the person who looked at it was driving it and changing settings then it sounds like he could have been trying to force a regeneration and reset the ash mass in the ECU. Also, not every warning light or limp home mode event will lead to a logged fault. It should do, but on numerous occasions we have checked vehicles for warning lights and no faults stored.

We have used the cleaner and had one customer say that it has not worked, everyone else has had positive results and no further issues.

With a replacement turbo we guarantee the work for two years, we do not guarantee the turbo cleaning but it is a lot cheaper than a replacement turbo. Turbo pipes off to turbo and takes around 2-3 hours start to finish including waiting for the cleaner to act. Not many BNZ or BPC turbo pipes fail either.

cheers and good luck.

 

[TH Performance]

A blocked DPF more than likely will not reset itself by turning the engine on and off. You would also probably have two to three warning lights on the dash alerting to you that there is a problem. Your described issue sounds very much like a turbo not DPF issue. If the person who looked at it was driving it and changing settings then it sounds like he could have been trying to force a regeneration and reset the ash mass in the ECU. Also, not every warning light or limp home mode event will lead to a logged fault. It should do, but on numerous occasions we have checked vehicles for warning lights and no faults stored.

We have used the cleaner and had one customer say that it has not worked, everyone else has had positive results and no further issues.

With a replacement turbo we guarantee the work for two years, we do not guarantee the turbo cleaning but it is a lot cheaper than a replacement turbo. Turbo pipes off to turbo and takes around 2-3 hours start to finish including waiting for the cleaner to act. Not many BNZ or BPC turbo pipes fail either.

cheers and good luck.

Agreed, a blocked DPF won't reset itself, however if you turn the ignition off and on the limp mode problem (which can be caused by blocked dpf) is temporarily resolved until it happens again.

A blocked DPF won't necessarily show up a fault (despite there being a warning light for the DPF in these vans) on the dash or in the ecu.

I know a company that cleans them out, but you can never be 100% certain all the ash/rubbish inside has been removed (wouldn't it be much easier if the DPF was a removable canister!!!!).

You can clean a turbo however you run the risk of contamination elsewhere however for most people it works as a temporary fix.

As for pipes coming off, it's a known problem, that's why companies like Forge Motorsport make a part especially to combat this problem.

http://www.forgemotorsport.co.uk/conten ... t=FMT5TBHC

I've not seen this van in the flesh but would be happy to inspect it free of charge and to provide the owner with an engineers report.

If i'm way off the mark I will take the owner and Alex the SMG guy for breakfast at my expense