Overboost/Limp mode

[dan_a3]

Firstly, my apologies for starting yet another limp mode thread, but after months of reading other posts, I feel it's finally time to admit defeat and enlist the help of others!

To begin, car is a 2007 2.0Tdi 140 BKD.

Over the last 3-4 months the car going into limp mode has got more and more frequent up until the point now where on a 50 mile motorway journey I'm having to reset the ignition 7+ times. Drives around town like a dream right up in the high rev ranges, only happens on motorways doing 65+mph and usually when climbing a slight incline or overtaking.

I'm well aware thanks to this site that the BKD is notorious for the vanes in the turbo sticking, so my first port of call was the well documented Mr Muscle treatment which I applied by taking the cat off. No luck. I then spent £50 odd quid on a Barhadhl VNT turbo cleaner which hasn't helped either. Then I started thinking what if it wasn't the vanes sticking?

Engine management light eventually came on giving me a P0234 overboost code, and suggested changing the map sensor. When I took the sensor out I noticed the pipe from the intercooler was gunked up with oil and the sensor also was. Replaced sensor and car drove fine. 40 miles into a journey (at this stage it was unheard of to go that long without going into limp mode) the dreaded happened again. Since then I have also taken the vacuum line that goes to the actuator off and sucked on it to see if the VNT rod travels down and holds in position to eliminate a vacuum leak. It seemed fine.

I'm no expert but would I be safe to assume that an intercooler pipe shouldn't be caked in oil, and that a map sensor wouldn't be giving a true reading if it was also caked in oil? Have attached pictures below and would love to hear anyone's ideas or similar situations. Last thing I want to do is spend hundreds that I haven't got getting the turbo replaced and have the same problem!

Thanks for reading my essay!

Dan

 

[T8DPR]

I NEVER use short cut methods when it overboosts, mine started to do it, had the turbo removed, stripped and cleaned, it's never done it since, i'm not sure how much the intercooler pipe would contribute to it overboosting

I'm assuming its only overboosting into limp mode at 3000+rpm?

Terraclean is getting more publicity of late, a process that basically cleans the fuel system right through to exiting the exhaust and seems to have good reviews? would be £108 for your car (enquired about mine since my local one is walking distance from my house)

 

[dan_a3]

Cheers for the reply.

Did your car have similar symptoms when you got the turbo stripped and cleaned? I'm just trying to eliminate my options before I bite the bullet and get it done as I've read so many other possibilities can cause it, ie wiring looms, actuators, vacuum leaks etc.

It generally goes into limp mode around 2000-2400rpm. Can pretty much guarantee if you're doing 65mph + and hit a slight incline, you'll overboost.

Terraclean sounds interesting, will have a look into it. Be interested to hear if anybody on here has had it done?

 

[Mujnu]

I NEVER use short cut methods when it overboosts, mine started to do it, had the turbo removed, stripped and cleaned, it's never done it since, i'm not sure how much the intercooler pipe would contribute to it overboosting

I'm assuming its only overboosting into limp mode at 3000+rpm?

Terraclean is getting more publicity of late, a process that basically cleans the fuel system right through to exiting the exhaust and seems to have good reviews? would be £108 for your car (enquired about mine since my local one is walking distance from my house)

Ive only ever heard about Terraclean from Ed China on wheeler dealers, is it really as good as Mr China made it out to be?

 

[ABS2788]

There's also carbon clean which similar to terra clean uses hydrogen and water to clean all the Coke and reviews are very positive about this treatment

 

[dan_a3]

Both of those options do sound very interesting and I'd be intrigued to hear from anyone who has had it done?
The thing that's throwing me at the moment, is that I'm 100% sure that fitting a new map sensor made a big difference, even if it was only for 40 odd miles. If it is the turbo vanes that are getting stuck open causing overboost then I can't understand why the new map sensor would have had an effect?

 

[phil miller]

next step is to remove the turbo and strip and clean it, ive never been a fan of the magic spray, its no where near as effective as a scot brite pad and a strip down

what fuel do you run it on (and dont say Diesel) is it supermarket? if so thats the reason

 

[dan_a3]

Yep usually just BP/Shell standard stuff.
Seen that there's a thread on here with a guide on removal and stripping, not sure if I'd attempt it myself though. Trouble is I'm assuming if you're paying a garage an hourly labour rate it's likely to be cheaper going with a factory reconditioned unit?

 

[phil miller]

Yep usually just BP/Shell standard stuff.
Seen that there's a thread on here with a guide on removal and stripping, not sure if I'd attempt it myself though. Trouble is I'm assuming if you're paying a garage an hourly labour rate it's likely to be cheaper going with a factory reconditioned unit?

avoid Euro car parts turbos, its around 4.5 hours, that said a good turbo and fitting, oil, filter, air filter asnd feed pipe will be around £800

 

[Mujnu]

Yep usually just BP/Shell standard stuff.
Seen that there's a thread on here with a guide on removal and stripping, not sure if I'd attempt it myself though. Trouble is I'm assuming if you're paying a garage an hourly labour rate it's likely to be cheaper going with a factory reconditioned unit?

CR Turbos have good reviews in regards to recon turbos and a little cheaper than turbo technics.

 

[dan_a3]

Thanks for all the replies and advice so far gents.
Little update- Yesterday I took the (new) map sensor out again and cleaned all of the oil off from the sensor part that sticks into the boost pipe. Did a 50 mile motorway journey last night and it flew up hills at 80mph no problem! 45 miles in, and it finally went into limp mode as I came off the accelerator to slow down for a roundabout on an A road, only noticed when I tried to pull off the roundabout!
Are we all definitely of the opinion that this saga with the map sensor and oil in the boost pipe is unrelated and that it's the turbo that's the problem? Just seems odd that this is the second time when either fitting a new sensor or cleaning and refitting the new one that it's made a distinct difference to the car. I do the same journey every week and of late I've been going into limp mode 7-8 times over the journey! Yet yesterday just the once and that was de-accelerating.

 

[ABS2788]

I would try order some dielectric grease from eBay and rub that on the connection of the map sensor, that way you eliminate any loose connections. I've ordered some just in case but been too lazy yet to put it on. Search it on here as I read about it on a previous post.

 

[dan_a3]

Haven't heard of that before but will definitely look into it! Sounds better than an £800+ new turbo job!

 

[Stuartgib]

Do not buy a turbo until you try the Hydrogen Carbon Clean i did and no more limp mode and running sweeter than ever 2006 TDI

 

[Bugeye_bob]

http://www.innotecworld.com/products/sets-systems.php?productid=6

tried and tested for DIY Vane cleaning. .

 

[Orange225]

I'm getting exactly the same symptoms with mine, I'm also convinced it's not the turbo sticking, drives absolutely fine for an hour or so on the motorway then dies on an uphill above 70mph, I can also get it to do it if I bury my foot on the throttle for over 8 seconds

 

[Dannymoto]

I'm getting exactly the same symptoms with mine, I'm also convinced it's not the turbo sticking, drives absolutely fine for an hour or so on the motorway then dies on an uphill above 70mph, I can also get it to do it if I bury my foot on the throttle for over 8 seconds

I had the issue of limp mode when up hill at 70mph. Was the turbo actuator not holding enough vacuum. New one sorted the problem and pulled so much better!

 

[Orange225]

Thankyou, I'll give that a try. I reckon I've got a leak somewhere too, it's very hissy on boost