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Author: Subject: Re post regarding turbo problems
Duncan Mould

posted on 20/3/11 at 10:09 PM Reply With Quote
Re post regarding turbo problems

Over boost on turbo (info re posted)

I have a Passat TDI 130 that has over boost problems. The car has done 200,000 but is a belting motor (just getting run in) about 3 months ago I had the turbo off and cleaned the vanes (and what a work of art that was) there was a great deal of end float in the main turbo impeller so a good quality replacement was sourced. This reduced the amount of smoke out of the exhaust and is now down to barely nothing, I don't use hardly any oil now compared to before. The problem lies when I take the car out of town and local running and put it on the motorway. In 6th gear the turbo over boosts at 2500rpm in 5th it will always over boost at 2800 and in 4th it will rev past 3000rpm (but I don't really want to thrash it). 6th gear at 2500rpm is about 75mph and returning 55mpg I am happy with that. I have contacts in the motor trade as I am an ex mechanic and have tried the car on 3 different code readers (Bosch KTS, Snap On Scanner, Some Pico tech software) and they all come up with the Over boost fault code ( which points to the solenoid).
A neighbor of mine is a parts lad at VW and got me the part at trade (he said it is always that that goes on them, we fit loads) it bolts to the front of the engine and has the 3 vac pipes going to it with an electrical multiplug connector on it. This has been on for about a fortnight now and is no different, I have even tried the old one back on. I have been altering the actuator arm length, took a measurement with a vernier caliper (recorded it) and adjusted it, but that has made little difference and have returned it back to its original length. I was thinking of replacing all of the vacum pipes this coming weekend but thought I would post on her to get some ideas and inspiration.
I hate it when the turbo drops out it is so lethargic its like superman and Kryptonite. Any suggestions gratefully appreciated.

This weekend I replaced all of the vac pipes and had the actuator off the turbo, sucked on the diaphragm and that is operating and holding well. I also worked the waste gate (or vane lever) and it all feels very free (in fact if you lift it up it drops easily). I set the actuator arm length so that the waste gate is shut when re fitted and watched it pull on when the engine rpm increased.
Pulling my hair out now, thanks for all the help and advice that you have all given me so far.

Any suggestions ?

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Bare

posted on 21/3/11 at 03:18 AM Reply With Quote
Didn't you post this winge previously?
a) could be the wrong ratio (turbine/compressor) Turbocharger.. really easy to do.
b) the solenoid valve is faulty? Bosch is not the erm.. world's best quality (despite all the brochure babble nonsense)

c) What does overboost actually mean? on your thing?
On MY planet overboost is ONLY a problem when the thing gets so high in boost pressure that the safeties cut in and turn off the fuel pump.. making my face aim directly and uncontrollably for the windshield.
It gets one's attention.. right quick :-)
My response has been to remap the ECU for a higher boost/safety threshold..
Ain't no such thing as 'too much power' in my view.

Please elaborate as to what it actually is that's upsetting you.

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MK9R

posted on 21/3/11 at 07:38 AM Reply With Quote
My Bora has started doing exactly the same last week. Have a read of this:-

http://forums.tdiclub.com/showthread.php?t=179589&highlight=limp+mode

I've checked MAF and vacuum hoses and can't find a problem, the N75 and N18 valves (the thing you replaced) seems to work ok, the actuator works ok and moves as described. So i'm now worried the vanes are jamming! Although it only happed once this morning after all the messing about.





Cheers Austen

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Antnicuk

posted on 21/3/11 at 07:39 AM Reply With Quote
you could try a new actuator if replacing all the vacume lines hasnt fixed it, you could have a split diaphram and its only under high boost that it is leaking air. As a test you could disconnect the actuator arm and drive it, you should see very little boost. Also, find out what stock boost should be at the engine and connect a boost gauge so you know if it is actually overboosting or it just thinks it is.





600 BHP per ton, Stylus Brought back from the dead! Turbo Rotary Powered!

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MK9R

posted on 21/3/11 at 07:44 AM Reply With Quote
i connected a vacuum gauge, at tickover the vacuum is stable at 25Hu, wondered if this means there is no leak?





Cheers Austen

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40inches

posted on 21/3/11 at 08:18 AM Reply With Quote
I had this on an A4, it was the vanes on the turbo sticking, a common problem apparently, after having a new turbo fitted, I found from a Audi forum that the vanes can be freed with WD40 and manually freeing them off( turbo off and dismantle). http://forums.tdiclub.com/showthread.php?t=140910
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Duncan Mould

posted on 21/3/11 at 09:17 AM Reply With Quote
Thanks for all of your help, knowing that I spent 3 hours on sunday systematically replacing all of the vacum hoses, even the ones that were an absolute pain to get at. When driving in to work today I was gutted when it did it again. Quite a lot of info to go on now, just printed off the thread from the TDI forum.
Thinking of going down the remap route I am thoroughlly fed up with this fault now and will reluctantly have to chuck some money at it.
Again thanks for your help, any other suggestions gratefully received, possibly locost engine re mappers in the midlands area.

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MK9R

posted on 21/3/11 at 09:22 AM Reply With Quote
quote:
Originally posted by Duncan Mould
Thanks for all of your help, knowing that I spent 3 hours on sunday systematically replacing all of the vacum hoses, even the ones that were an absolute pain to get at. When driving in to work today I was gutted when it did it again. Quite a lot of info to go on now, just printed off the thread from the TDI forum.
Thinking of going down the remap route I am thoroughlly fed up with this fault now and will reluctantly have to chuck some money at it.
Again thanks for your help, any other suggestions gratefully received, possibly locost engine re mappers in the midlands area.


mine already has the 145bhp remap, and i was starting to wonder if that is anything to do with it! I'm just trying not to have to strip turbo and/or clean out EGR/intake plenum as its a real PITA!





Cheers Austen

RGB car number 9
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Duncan Mould

posted on 21/3/11 at 09:52 AM Reply With Quote
Thats the easy part and stuff I dont mind doing. Its the black art of electronics and managment systems that I can never get my head around.
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vinny1275

posted on 21/3/11 at 10:02 AM Reply With Quote
While you were doing the vacuum pipes, did you look at the "solid" plastic ones? I just found big gouges in two the them in my car over the weekend, it's now a completely different car to drive - I'd got so used to having to rag it everywhere to get it to move without full / any turbo, at the first set of lights I got to after fixing it I almost painted an 11 on the tarmac.....






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MK9R

posted on 21/3/11 at 10:05 AM Reply With Quote
i disconnected the pipe from the vacum ball thingy and connected my mytivac to the pipe, it shows a leak in the system somewhere as it dropped. But then i realised the N75 and 18 valves vent to atmosphere if the diaphragm is in the one position, does this sound right?





Cheers Austen

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Duncan Mould

posted on 21/3/11 at 01:23 PM Reply With Quote
if its the one that resembles a ball cock then no it should hold the pressure.
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MK9R

posted on 21/3/11 at 01:25 PM Reply With Quote
quote:
Originally posted by Duncan Mould
if its the one that resembles a ball cock then no it should hold the pressure.


sorry no, removed the pipe from this and stuck my mytivac onto the pip to test the system, not the ball cock





Cheers Austen

RGB car number 9
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Duncan Mould

posted on 21/3/11 at 03:37 PM Reply With Quote
That makes more sense. I have not had much success in the past with a mitivac. I did however manage to connect it to the actuator and drive it up the road varying my boost level (very Mad Max style).
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Bare

posted on 21/3/11 at 05:42 PM Reply With Quote
I'm still not comprehending what the issue is?
Overboost is just a word, with scant informational content.
Is your boost gauge.. should you have one, going past the red zone?
Is your car accelerating uncontrollably?
Is simply pulling 'harder' than before the 'repair'?
What actually happens to/in the car when 'overboosting'?

[Edited on 21/3/11 by Bare]

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bertie_bas205

posted on 22/3/11 at 03:26 PM Reply With Quote
I would fit a Boost gauge, even if its temperary just to see what its boosing at....

Find out the max boost of your car, ye dont want it above that or all hell can break loose.....

In my opinion, i would try and find the problem rather than remap to match the boost...

Is there any smoke coming from the exhaust??

Over boost, too much pressure being forced into cylinders...?? Is that what yer meaning??

My G/F has a Passat 4 Motion 1.9 tractor (read TDi) and its nearly 200 horse, they can shift when set up/running right....




Bertie.






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bertie_bas205

posted on 22/3/11 at 03:34 PM Reply With Quote
Hmmm, maybe another angle to this....

When in 6th and reaching 2500rpm does the revcounter go up and ye dont go any faster or accelerate??

is that what ye mean?



Bertie.

[Edited on 22/3/11 by bertie_bas205]






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Duncan Mould

posted on 23/3/11 at 09:48 AM Reply With Quote
When I say its over boosting. you can be driving along NORMALLY or want to overtake someone then the turbo stops working. A solenoid shuts the air supply off to the actuator and the turbo still spins but does not provide boost to the inlet.
Basically when it over boosts the turbo stops working. Overboost is in place to stop the engine from exploding.
As I understand it.

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MK9R

posted on 23/3/11 at 10:08 AM Reply With Quote
well mines gone completely tits, no turbo at all now and plenty of black smoke!!! Gonna have to get it into a diagnostics place!!! But can i get anyone to look at it today round here, can i balls!!!! ggggrrrr!!





Cheers Austen

RGB car number 9
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bertie_bas205

posted on 23/3/11 at 10:30 AM Reply With Quote
quote:
Originally posted by Duncan Mould
When I say its over boosting. you can be driving along NORMALLY or want to overtake someone then the turbo stops working. A solenoid shuts the air supply off to the actuator and the turbo still spins but does not provide boost to the inlet.
Basically when it over boosts the turbo stops working. Overboost is in place to stop the engine from exploding.
As I understand it.


Overboost generally means that there is too much Volume/air being forced into the engine, resulting in "locking/slowing" of the pistons..... There is fitted to most cars an electronic boost controller, this usually lets the boost (Example) sit at 8psi then when ye floor it to overtake it'll allow more boost say, 12psi to be reached.

The actuator works the wastegate, there for when max allowed boost is reached anything over that will be dumped, either down through the exhaust or vented to atmosphere if an external waste gate is fitted... It is a safety valve to protect your engine.... Over boosting can lead to bent conrods and holes in blocks!!!



Bertie.






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bertie_bas205

posted on 23/3/11 at 10:36 AM Reply With Quote
quote:
Originally posted by MK9R
well mines gone completely tits, no turbo at all now and plenty of black smoke!!! Gonna have to get it into a diagnostics place!!! But can i get anyone to look at it today round here, can i balls!!!! ggggrrrr!!


I'd have a good look at the induction side of things from the turbo to the inlet.Inercooler and pipes etc. My G/F's car was doing similar, it was a boost pipe off and the black smoke out the back was something else...

The black smoke is caused by the ecu telling pump to fuel but theres isnt enough air going into the engine....

They have a few weaknesses... the silly wee clips to hold the boost pipes on are crap, they also have a tendancy to crack the inter cooler....

Listen for a whooooshin sound when yer accelerating.....



Bertie.

P.s, her car is fitted with twin tail pipes, the black smoke out of them both looked a bit mad max....






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MK9R

posted on 23/3/11 at 10:38 AM Reply With Quote
quote:
Originally posted by bertie_bas205
quote:
Originally posted by MK9R
well mines gone completely tits, no turbo at all now and plenty of black smoke!!! Gonna have to get it into a diagnostics place!!! But can i get anyone to look at it today round here, can i balls!!!! ggggrrrr!!


I'd have a good look at the induction side of things from the turbo to the inlet.Inercooler and pipes etc. My G/F's car was doing similar, it was a boost pipe off and the black smoke out the back was something else...

The black smoke is caused by the ecu telling pump to fuel but theres isnt enough air going into the engine....

They have a few weaknesses... the silly wee clips to hold the boost pipes on are crap, they also have a tendancy to crack the inter cooler....

Listen for a whooooshin sound when yer accelerating.....



Bertie.

P.s, her car is fitted with twin tail pipes, the black smoke out of them both looked a bit mad max....


thats the thing, i cant hear any whoosh, so assuming turbo is not spinning





Cheers Austen

RGB car number 9
www.austengreenway.co.uk
www.automatedtechnologygroup.co.uk
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bertie_bas205

posted on 23/3/11 at 10:47 AM Reply With Quote
quote:
Originally posted by MK9R
quote:
Originally posted by bertie_bas205
quote:
Originally posted by MK9R
well mines gone completely tits, no turbo at all now and plenty of black smoke!!! Gonna have to get it into a diagnostics place!!! But can i get anyone to look at it today round here, can i balls!!!! ggggrrrr!!


I'd have a good look at the induction side of things from the turbo to the inlet.Inercooler and pipes etc. My G/F's car was doing similar, it was a boost pipe off and the black smoke out the back was something else...

The black smoke is caused by the ecu telling pump to fuel but theres isnt enough air going into the engine....

They have a few weaknesses... the silly wee clips to hold the boost pipes on are crap, they also have a tendancy to crack the inter cooler....

Listen for a whooooshin sound when yer accelerating.....



Bertie.

P.s, her car is fitted with twin tail pipes, the black smoke out of them both looked a bit mad max....


thats the thing, i cant hear any whoosh, so assuming turbo is not spinning


Asumption is the root to all cock ups.....

It could be a few different things so dont get blinkered into turbo problems...

I couldnt really hear it in my G/F's car, get someone to drive yer car (past ye so ye can hear it), you'll probably notice a different sound. When her cooler went, it didnt really make as much noise but did the black smoke thing....




Bertie.






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MK9R

posted on 23/3/11 at 10:48 PM Reply With Quote
Well i came home with the AA, started it up at work, loads of smoke out the back, so much so when i drove for a couple of miles there were no cars visable behind me. Oil all over the back of the car and dripping from the tail pipe, looked at turbo and its also dripping with oil, so i'm guessing the trouble was all to do with the oil seals and/or bearings going on the turbo!! So thats a new turbo required i guess, or put the thing on ebay as it is.....





Cheers Austen

RGB car number 9
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coyoteboy

posted on 24/3/11 at 01:49 AM Reply With Quote
quote:
When I say its over boosting. you can be driving along NORMALLY or want to overtake someone then the turbo stops working. A solenoid shuts the air supply off to the actuator and the turbo still spins but does not provide boost to the inlet.
Basically when it over boosts the turbo stops working. Overboost is in place to stop the engine from exploding.
As I understand it.


Terminology fail

Overboost is when the turbo produces pressure higher than that requested of it, through failure of the control system (solenoids, vac lines, actuator, stuck wastegate etc). What you're thinking of is overboost protection, this is where the turbo has done the above and the ECU stops it getting any worse, usually by cutting fuel and/or spark if in a SI engine, and sometimes by closing the boost reference bleed solenoid valve to return you to base boost. Things to note:

1) If it were overboost protection you'd get full acceleration and more until the first occurance. Once triggered the ECU on an SI engine will then not allow you back into positive manifold pressure until the problem is solved or the ignition re-set, D's are a tad more complex and will allow some boost usually but very low and limit revs.

2) If a solenoid switched off the air to the actuator you'd see silly boost.

3) If the turbo is spinning as expected, it WILL produce boost, in order for it not to it would have to have the wastegate jammed open.

4) This opens up a whole heap of additional possible faults, real overboost is fairly easy to fix, an ECU going mental could be caused by a whole heap of sensors, mechanical and electrical faults!

I know it sounds pedantic, but being pedantic reduces confusion - this is why I find lots of car forums intensely irritating and full of myths and legend.

[Edited on 24/3/11 by coyoteboy]

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