blow off valve noise when shifting or letting off gas on td4

P

Petoors

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6

• Sep 17, 2013

• #1

Hi guys,

My Freebie 1 td4 auto has developed a whistling noise when the auto box shifts or you let off the gas quickly while under boost almost like a blow off valve. as well as a tendency to go into limp mode with a check engine light while cruising on the highway around 130km/h and as soon as you reduce the speed, the CEL goes off and it goes out of limp mode. No Fault codes......

i have serviced it, and replaced all the filters, as well as all vacuum lines, and two of the turbo hoses, the others is still in good nick.

If anyone can please give me an idea of what to look for i would appreciate it!

 

SES88

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North East

• Sep 17, 2013

• #2

All turbo systems have a vent to allow excess boost pressure to escape, it's normal. Unless you've actually got a boost leak from a hose somewhere but that wouldn't give you the BOV whistle sound. As for the CEL, someone with more technical knowledge will be along soon

 

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• Sep 17, 2013

• #3

It did not always make the noise, only started about two weeks ago, and its not a thssssss noise like a petrol bov, its more of a whistle if you understand what I mean?:confused2:

 

SES88

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• Sep 17, 2013

• #4

If its a whistle i'd be more inclined to say its a boost leak

 

teddywood1

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stoke-on-trent

• Sep 17, 2013

• #5

check those clamps on you turbo hoses they tend to come a bit loose as the hose settles in

 

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• Oct 2, 2013

• #6

Hi Guys,

Just a Reply to let you know the problem is solved, I figured that the two boost hoses that burst recently could have something to do with the problems I was having and I was right. turns out the vacuum solenoid that controls the boost was faulty, and that caused it to overboost a lot, causing the BOV noise and the CEL as well as the two hoses that failed, replaced it and its running like a dream again, bar for the crank pulley that decided to break just after I ordered the vacuum solenoid. could not find a aftermarket one in SA, so it was stealers 1, Petoors 0.