fluorspar Posted August 31, 2005 Report Share Posted August 31, 2005 Hi Folks, This is my first post on here. I would like to relate my tale of woe and hopefully get some advice or encouragement. I recently purchased my first VW. A Golf MK4 TDI SE 1.9 90hp engine model ALH. My cars problem is the dreaded Limp Mode when the engine is under load. In lower gears its ok. I can redline it 2nd without the turbo cutting out. In 3rd it cuts out at around 4000rpm. In 4th it cuts out at 3500rpm etc…... you get the picture. Worst case is on hills in the higher gears. Well… I spent a lot of time reading the posts on this forum and gained a lot of very useful knowledge about this problem. But one by one, all the cures I tried proved ineffective. The vacuum lines appeared fine, as far as I could see. The VNT arm had plenty of movement. I tried running the car with the MAF unplugged, but it seemed to run worse. Bad news that. My hopes of a quick fix were fading fast. Anyway… in desperation I went and fitted a new MAF. No difference at all. ( But at least I have a good working spare ! ) Ok… time for a new approach. With the engine having done 55k miles I decide to put it into a VW franchised garage for a new timing belt, and ask them to investigate the limp mode at the same time. I leave the technician copious notes on what I had already tried and what I was unable to test ( MAP sensor for example ) The garage phones me and says “Yes you are correct, its not the MAF, it’s the TURBO !! The vanes are all coked up, we get this problem from time to time. We can fit a new one for £900.” It took me the best part of a day to recover from the shock, but I bite the bullet and give them the go-ahead. But armed with advice from this wonderful forum, I ask that the old turbo be returned to me. The service manager sounded hesitant as though this was an unusual request. Shortly afterwards, he phones me and says, “Sorry Sir, but we keep the old turbos, they are a service exchange item” Really…. Hmmm well what happens to all these old turbos ? We recondition them Sir. Oh …. Really ??? well then, why was I not offered a reconditioned unit ??? The unit we proposed fitting WAS a reconditioned unit because these turbos are not available anymore, he says. I am totally speechless at this point, but summon up enough strength to tell him to take a running jump. £900 for a second hand unit …. LOL I could sniff the crap coming out of the phone. They did a good job on the timing belt though….. Anyway, I still have made no progress in curing the fault. I am looking at removing the turbo myself and having it reconditioned. This will be a big job for me and I am not really looking forward to it. Does any of this sound familiar to anybody ? Any advice etc would be gratefully received. Link to comment Share on other sites More sharing options...
Rustynuts Posted August 31, 2005 Report Share Posted August 31, 2005 Morning, mate. Good to see someone having a look round and reading before posting. The dealers are talking crap about the turbo not being available anymore. Absolute crap. They may well be fitting a recon unit, but it's far from second hand. All the recon turbos are sent to be remanufactured and should come back as good as a new unit. All they do is re-use the shell and various other bits, replace bearings etc. and replace all items of wear. It's also common practice with items such as starter motors, alternators, etc. You could take your turbo off and have it recon'ed or remanufactured aswell and save their labour charges. Or you could always take it off, and have a look at cleaning the vanes yourself. If you want a good insight into how your turbo works, have a look at this thread. web page. Link to comment Share on other sites More sharing options...
Wobby Posted August 31, 2005 Report Share Posted August 31, 2005 I probably have nothing to add to this thread! Hopefully you had a good holiday besides the problems with the daughter rusty. Does it not seem strange that it runs ok foot flat down to the red line in 2nd? Or is this because there is less load on the engine/turbo in lower gears? Will the build up on the vanes cause increased or decreased boost? I think it sounds more like a control/ sensor fault. Can you use VAG COM to do some boost/ maf logs etc? Link to comment Share on other sites More sharing options...
Rustynuts Posted August 31, 2005 Report Share Posted August 31, 2005 [ QUOTE ] Does it not seem strange that it runs ok foot flat down to the red line in 2nd? Or is this because there is less load on the engine/turbo in lower gears? [/ QUOTE ] [ QUOTE ] Will the build up on the vanes cause increased or decreased boost? [/ QUOTE ] Depends where they stick. Link to comment Share on other sites More sharing options...
fluorspar Posted August 31, 2005 Author Report Share Posted August 31, 2005 Oracle Rustynuts & Wobby, Thanks very much for the fast reply. Unfortunatly I dont have access at this time to VAG COM ... so I cant supply any fault codes. I really think its up to me to get the turbo out & cleaned. I really would prefer to this myself, but I am a bit concerned about something I read regarding "the turbo needs balancing to its manifold". I dont know what this means, but it sounds serious if strip the thing for cleaning & upset this "balance". Has anybody on here done this job ? Link to comment Share on other sites More sharing options...
Wobby Posted August 31, 2005 Report Share Posted August 31, 2005 So the turbo is effectively stalling? I was thinking it was generating less or more boost through this build up. Do the MAP sensors fail? Can he clean the turbo himself? What would you clean it with? Is it a case of scraping the carbon off carefully? Link to comment Share on other sites More sharing options...
Wobby Posted August 31, 2005 Report Share Posted August 31, 2005 spins very fast, wont run long if its out of balance. Where do you live, maybe someone near may have a VAG COM and be able to help you. It would be terrible if you recon the turbo (£400) and then find the problem is still present. Link to comment Share on other sites More sharing options...
Rustynuts Posted August 31, 2005 Report Share Posted August 31, 2005 I think what you may be thinking about is the setting of the control arm from the actuator to the VNT mechanism. This has to be set so that the vanes are at the correct setting when at idle, and moves the vanes to the correct place when full boost is required. If you just strip it and clean it, then there'll be no need for any adjustment as you'll just be restoring the original settings. At the moment, the actuator will be trying to push and pull the vanes to their full extent, and the carbon build up will be interfering with this. Clean the carbon, and back to normal. If you get the turbo rebuilt professionally, they should be able to advise on setting this for you. Link to comment Share on other sites More sharing options...
Rustynuts Posted August 31, 2005 Report Share Posted August 31, 2005 [ QUOTE ] So the turbo is effectively stalling? I was thinking it was generating less or more boost through this build up. [/ QUOTE ] If the vanes are correctly at rest, then all reads well between the ecu and the MAP sensor at idle. When the ecu calls for full boost and the vanes stick before full boost is achieved, then the difference in "required boost" by the ecu and "actual boost" read from the MAP sensor kicks it into limp mode. Fault shown would be "17964 - Charge Pressure Contr. Negative Deviation" If the vanes are sticking (not returning to rest properly) and giving too much boost at idle, then the fault code would be shown as "17965 - Charge Pressure Contr. Positive Deviation" [ QUOTE ] Do the MAP sensors fail? [/ QUOTE ] Sometimes. Not common. [ QUOTE ] Can he clean the turbo himself? What would you clean it with? Is it a case of scraping the carbon off carefully? [/ QUOTE ] Yep, very carefully with the VNT assembly and ultra carefully with the turbine. Link to comment Share on other sites More sharing options...
shao_khan Posted August 31, 2005 Report Share Posted August 31, 2005 Hi Fluorspar - Welcome to tyresmoke. Sorry to hear of the problems you are experiencing, I cant add anything to what has been offered above. IF you get a chance I would appreciate if you could give a review of the particular VW Franchised Dealer you were refering to in our Dealer section as we are trying to build up information to help others when they are looking for service / sales centres. Link to comment Share on other sites More sharing options...
fluorspar Posted September 2, 2005 Author Report Share Posted September 2, 2005 Hi Folks... Just an update. Recently I have been much more violent with the old accelerator pedal and I think the car seems to like it. On a few occasions I have redlined it 2nd, 3td and 4th without the turbo cutting out, but on most occasions especially going up hill it cuts out at between 3-4000 rpm. Anyway testing & investigations continue.... This evening I decided to reassure myself that the VNT actuator arm was indeed not stuck, and wary of hurting my delicate fingers & thumbs, I have invented the delux VNT Exersiser. (Pictures attatched) This unique device cunningly fashioned from 2 stout cable ties, is operated from below the car. It is passed over the top of the actuator arm, thus affording an easy means of both pulling with one hand and pushing with the other. Lubrication can also be applied to ease the process. Patents Pending. ...... Take care all. Link to comment Share on other sites More sharing options...
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