Vito 112 turbo dropout saga

simon harper

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Vito 638 112
This issue has been ongoing for a few years and i have done various jobs to try fix it, i shall try briefly summerise:
Turbo would dropout on long journeys, i would stay gone until i parked up and work for another while on the next drive. this got progressively worse-ie would happen sooner.
I had 2 errors, boost pressure sensor and boost pressure- the mechanic who looked at the van reckoned it was not a mechanical issue but was probably a bad sensor/connection.
I changed the pressure sensor just beside and above the air filter-no change
i changed the transducer (not sure if this is what it is called) which is connected to the turbo actuator - no change
I then noticed a rather large hole in the intercooler pipe which was also changed- this made a difference but did not solve the problem, i had turbo longer but would still drop out, when overtaking i found there was a sweet spot where i could sustain turbo by not accelerating too fast or too much.
Recently i went at this again and found that the actuator arm/wastegate was totally ceased, either in the closed or nearly closed position, having freed up the gate/arm i now have a new issue- no turbo at all, its like before but worse, but also works perfectly once started!, i can take off great but after one or two gear changes the actuator just stops working. So with a cold start the wastegate is open, once started it closes- i can drive for a gear change or two and then it stops working, the actuator arm moves freely when the engine is running.
Ive been checking the vacuum system and cant seem to find any leaks-however before i changed the intercooler pipe, i checked the brakes and thenheadlight adjust and both worked- now ive noticed than when the turbo is dead, the headlight adjust works but there is no hiss, while if i check this once ive started engine i can hear the hiss. its like the vacuum system has a fault or a leak that is intermittent , the brakes seem the same as ever. (if i disconnect a vacume pipe from a headlight, i can hear hissing from the adjustment dial on the dash)
Can anyone suggest anything else i can do to track down this error? what generates the vacuum and is there any reason this would sporadically work?
At the beginning when the turbo dropped out i believe it was limp mode, while now its just slow, but i can rev the engine past 3k when in neutral.
Any input to help solve this irritating issue would be fantastic
 

bembo449

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I reckon you've defo got a split pipe pal , get someone to rev it while you listen out for it , they can be a pita to locate and don't rule out a split intercooler either
 
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simon harper

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I reckon you've defo got a split pipe pal , get someone to rev it while you listen out for it , they can be a pita to locate and don't rule out a split intercooler either
Do you mean a vacuum pipe or air cycling through the turbo, what would cause it to work to begin with and fail once i change gear?
 

bembo449

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could be any pipe pal but more likely a boost hose if the vac lines are all in decent nic but check all the hoses to do with the turbo / intake set up inc exhaust , there really shouldn't be any hissing at all pal
 


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