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Discussion Starter #1
So bought 99 t4 to convert, was standing for long time. Gave it a blast down the road drove ok. Whining turbo so sent to Midland turbos they cleaned and checked said it was ok. Refitted it and still white smoke when turbo kicks in. Took it off and oil in port on turbo e exhaust ports are dry, feed and return pipes clear no real pressure in crankcase. Egr and inlet manifold cleaned . Resent back to Midland turbo again all ok within spec. So what have I missed why excessive white smoke when accelerated. Could do with some constructive advice please. Cheers Martin.
 

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Behind the coolant expansion tank are two valve block things .One operates the egr on instruction from the ecu .The other is connected to the inlet and pressure sides of the turbo and to the diaphragm which operates the turbo waste gate .the ecu receives inputs from the pressure sensors and depending on the demands being made on the engine will instruct the gate to open and close .If the pipes or the valve itself are not in order then the ecu will possibly instruct the pump to overfuel which will give you white smoke .Think this is what you should investigate now .
 

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Correction there is no waste gate ,the diaphragm operates a rod which opens and closes the vanes in the variable nozzle which in turn controls the amount of exhaust gas impinging on the turbine
 

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So bought 99 t4 to convert, was standing for long time. Gave it a blast down the road drove ok. Whining turbo so sent to Midland turbos they cleaned and checked said it was ok. Refitted it and still white smoke when turbo kicks in. Took it off and oil in port on turbo e exhaust ports are dry, feed and return pipes clear no real pressure in crankcase. Egr and inlet manifold cleaned . Resent back to Midland turbo again all ok within spec. So what have I missed why excessive white smoke when accelerated. Could do with some constructive advice please. Cheers Martin.
White smoke normally indicates worn/dirty injectors or on some occasions fuel pump timing. I'd check your pump timing first. If that's around the .55 mark suspect the injectors may need a refurb. Especially if you have an 88bhp AJT engine.
 

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Discussion Starter #5
It is ajt engine . This was my turbo after less than 2 mins of running. I was told twice by a turbo specialist that it was ok after paying £210 having it serviced and sent back to be washed and checked again. I have an aftermarket upgrade box which I have been told this could also been a factor. But oil on exhaust impeller is a concern. Currently at another turbo specialist for reconditioning.
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181863
 

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All turbo cartridges have seals on each end. Engine oil is pumped through the turbo to keep oiling the bearings. The bearings in the turbos used on VW and many other cars today are a throw away turbo cartridges because there is no seal only bushes that ware out and let the engine oil be pumped up and into the inlet manifold. If you remove the outlet hose from the turbo and is wet with engine oil your turbo is feeding the oil into the inlet manifold. I found my ACV engine had wet oil in the outlet hoes up to the after cooler and into EGR valve and lots which was stick to there inside of the inlet manifold. It must have been about 3 mm thick all in side the wall of the inlet manifold. Once cleaned which was no easy way but by high pressure washer. A big job to remove the inlet manifold. But my VW t4 transporter went in to limp mode and after see what the engine was doing I decided to replace the turbo cartridge.

Now you guy's that lose power on hills is the reason not the turbo it's the Boost solenoid N75 if you have a ACV engine if other engines it's the N18 valve. on the intake pipe that come from your air filter there is a pipe that goes to your N75 valve and in most cases it is blocked and the N75 valve is also full of **** and that is why the N75 valve doesn't work at all and your VW goes into limp mode. great down hills but not going up. You can use a N18 valve as it works about the same. If your VW van has the two valve like mine and the N75vyou will not find any where in the world so use the N18 valve which they are still around to buy.
Hope this helps.
 
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