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General => The garage => Topic started by: scarr89 on 15 September 2012, 18:08

Title: Limp mode virgin/Turbo blown
Post by: scarr89 on 15 September 2012, 18:08
Hit limp mode on a spirited drive earlier today, well I assume it was limp mode as there was minimal boost (measured on boost gauge), I restarted and she was boosting, but not as it normally does. I was hitting my 'normally measured' peak figures but it was no where near as powerful as normal.

I know I should be checking for hoses popped off etc, time isn't allowing me to jack it up at the mo so will be doing first thing in the morning. I'v had my bro revving and me listening and there defo sounds like a leak/hissing coming the engine bay....

ALSO when shutting down it makes a kind of hissing noise and sounds as if air is escaping from somewhere, compared to my bro 130s which shuts down immediately after key turn.

I hope it isn't my turbo...But am I right in thinking that if it there is normally loads of smoke? There is no/little signs of any coloured smoke.

The car in question is a mk4 150PD, 126k, decat, EGR delete, stage 1 map...Can anyone help?
Title: Re: Limp mode virgin/Turbo blown
Post by: DCmk3 on 15 September 2012, 18:19
At times a blown turbo wont produce smoke, and at times it will, for example a seized turbo and the seals are gone, you will have a massive amount of smoke.

If you rev does it have a sort of "blow off" valve sound like dumping all the boost? You may have blown a pipe off the diverter valve, I've managed that before on a 1.8T after testing it out once work had been done, it had the same results, a hissing/blowing sound and no real power.

Oh and on idle, how are the revs? Stable or fluctuating?
Take a look at the PCV valve and the diverter valve, make sure the pipes are all on tight.
Title: Re: Limp mode virgin/Turbo blown
Post by: scarr89 on 15 September 2012, 18:25
At times a blown turbo wont produce smoke, and at times it will, for example a seized turbo and the seals are gone, you will have a massive amount of smoke.

If you rev does it have a sort of "blow off" valve sound like dumping all the boost? You may have blown a pipe off the diverter valve, I've managed that before on a 1.8T after testing it out once work had been done, it had the same results, a hissing/blowing sound and no real power.

Oh and on idle, how are the revs? Stable or fluctuating?
Take a look at the PCV valve and the diverter valve, make sure the pipes are all on tight.

Idle revs are fine no issues at all, no blow off valve sound, more of a constand whistle. All of the valves and pipes, that I can see without getting under the car, are intact  :lipsrsealed:
Title: Re: Limp mode virgin/Turbo blown
Post by: DCmk3 on 15 September 2012, 21:04
Sounds like a boost leak then.. perhaps a clamp on one of the hoses isn't tight enough..
Title: Re: Limp mode virgin/Turbo blown
Post by: Rhyso on 15 September 2012, 21:27
Good luck finding the DV and PCV valve mind............ :whistle:

Do you get black smoke out of the back as thats a normal sign of a boost leak?  Also check for oil around the boost pipe connections; another tell tale sign of escaping boost

The ecu should have stored a fault code so get it on VAGCOM  :wink:
Title: Re: Limp mode virgin/Turbo blown
Post by: scarr89 on 15 September 2012, 21:53
Good luck finding the DV and PCV valve mind............ :whistle:

Do you get black smoke out of the back as thats a normal sign of a boost leak?  Also check for oil around the boost pipe connections; another tell tale sign of escaping boost

The ecu should have stored a fault code so get it on VAGCOM  :wink:

No black smoke as yet, and drove about 4 miles like it...however i had dreadful mpg. Can it not smoke and be a boost leak :embarrassed:  :undecided:

Will be checking her out tomorrow and then vagcoming her and logging also...i have a 200mile trip to make tomorrow so i hope it is fixable! I dont think it is the tappets either, doesnt fit the description of cams going
Title: Re: Limp mode virgin/Turbo blown
Post by: Rhyso on 15 September 2012, 21:55
Good luck finding the DV and PCV valve mind............ :whistle:

Do you get black smoke out of the back as thats a normal sign of a boost leak?  Also check for oil around the boost pipe connections; another tell tale sign of escaping boost

The ecu should have stored a fault code so get it on VAGCOM  :wink:

No black smoke as yet, and drove about 4 miles like it...however i had dreadful mpg. Can it not smoke and be a boost leak :embarrassed:  :undecided:

Will be checking her out tomorrow and then vagcoming her and logging also...i have a 200mile trip to make tomorrow so i hope it is fixable! I dont think it is the tappets either, doesnt fit the description of cams going

Have you driven it since it hit limp mode??

Was it stuttery? Or just flat??
Title: Re: Limp mode virgin/Turbo blown
Post by: scarr89 on 15 September 2012, 22:29
Good luck finding the DV and PCV valve mind............ :whistle:

Do you get black smoke out of the back as thats a normal sign of a boost leak?  Also check for oil around the boost pipe connections; another tell tale sign of escaping boost

The ecu should have stored a fault code so get it on VAGCOM  :wink:

No black smoke as yet, and drove about 4 miles like it...however i had dreadful mpg. Can it not smoke and be a boost leak :embarrassed:  :undecided:

Will be checking her out tomorrow and then vagcoming her and logging also...i have a 200mile trip to make tomorrow so i hope it is fixable! I dont think it is the tappets either, doesnt fit the description of cams going

Have you driven it since it hit limp mode??

Was it stuttery? Or just flat??

It wasnt stuttery, which is why i feel it could be worse than just a blown pipe  :-( it was far less pokey, and generally flat, evem in 3rd at low rpm where im normally pulling several g ;-) i jest...but normally im getting quite a bit of boost compared more of a flat, continuous boost level BUT at similar boost levels to before :-\
Title: Re: Limp mode virgin/Turbo blown
Post by: Rhyso on 15 September 2012, 22:47
What PSI was showing on your boost gauge??
Title: Re: Limp mode virgin/Turbo blown
Post by: scarr89 on 15 September 2012, 23:04
What PSI was showing on your boost gauge??

I left Rtech with an overboost spike of 29psi in almost every gear and today after o 'reset' after limp mode i was hitting 25/27 psi WOT in 3rd and 4th. I  was doing some 'self diagnpstics' on my way back, wasnt just driving like a tool :-\  was holding about 20psi iirc :-\
Title: Re: Limp mode virgin/Turbo blown
Post by: scarr89 on 16 September 2012, 11:34
Just vagcomed, error code 17965 which is sticky VNT right...Strange how it has just happened now. I don't drive it like an old lady. Could it just have that problem when cold, or does heat not affect it? Could a fault N75 cause this issue?

I am going to check all the pipes now and possibly try a different N75...I do not have the time to clean the turbo today but maybe a job for the weekend!
Title: Re: Limp mode virgin/Turbo blown
Post by: scarr89 on 16 September 2012, 12:15
One of the lower IC pipes was slightly popped off, now back on all nice and tight. Have checked the actuator and it doesn't seem to be sticking... :undecided:
Title: Re: Limp mode virgin/Turbo blown
Post by: DCmk3 on 16 September 2012, 15:11
The boost leak was possibly causing the sticky VNT surely?
Title: Re: Limp mode virgin/Turbo blown
Post by: scarr89 on 16 September 2012, 15:27
The boost leak was possibly causing the sticky VNT surely?

I don't get why it would though  :undecided:

I checked all the pipes, all the vacuum lines etc, all seemed fine. No leaks coming from any joins/blown gaskets etc and when shutting down it shut down straight away, no hissing noise.
 
Took it for a test drive and it seemed to drive well, I have it maybe 3/4 throttle up hill in 3rd, so plenty of opportunity to hit limp mode if it wanted to...Will keep an eye on it and will invest in some innotec turbo clean.  :lipsrsealed:
Title: Re: Limp mode virgin/Turbo blown
Post by: Rhyso on 16 September 2012, 15:29
Id be replacing the pipe. Chances are the lugs are worn and will pop out again sometime soon....
Title: Re: Limp mode virgin/Turbo blown
Post by: scarr89 on 16 September 2012, 15:32
Id be replacing the pipe. Chances are the lugs are worn and will pop out again sometime soon....

I checked it out, and they seem fine, just 126k worth of wiggling itself loose a touch. I need to have a proper look at my IC in general though, seems to be quite a lot of crud at one end of the IC joins  :undecided:
Title: Re: Limp mode virgin/Turbo blown
Post by: Rhyso on 17 September 2012, 11:38
Id be replacing the pipe. Chances are the lugs are worn and will pop out again sometime soon....

I checked it out, and they seem fine, just 126k worth of wiggling itself loose a touch. I need to have a proper look at my IC in general though, seems to be quite a lot of crud at one end of the IC joins  :undecided:

They shouldn't move really though  :huh:  At that age I'd expect the lugs to be worn  :sad:
Title: Re: Limp mode virgin/Turbo blown
Post by: scarr89 on 17 September 2012, 16:58
I'll get it on the ramp this weekend and see if it has moved at all  :undecided:

I managed to sort the problem, but I didn't really do anything, apart from clip that pipe back in place. She drove flawlessly on my 200mile trip yesterday, hit over 55mpg and was boosting fine. I think I may remove the turbo and strip it down and clean it out...What you reckon?  :lipsrsealed:
Title: Re: Limp mode virgin/Turbo blown
Post by: Rhyso on 17 September 2012, 16:59
If it ain't broke, don't fix it  :lipsrsealed:  :laugh: :laugh:
Title: Re: Limp mode virgin/Turbo blown
Post by: scarr89 on 17 September 2012, 17:14
If it ain't broke, don't fix it  :lipsrsealed:  :laugh: :laugh:

I like that...If it happens again then I'll take some drastic action perhaps!