That's what I'm thinking, il go get 5 meters of silicone vac pipe and start replacing vac pipes etc, if I get it done early enough and it fails to resolve the problem il then remove the exhaust from the turbo and use the Mr muscle failing that il know it's not the vanes blocked in the turbo and it wouldn't be a vac problem, then I've eliminated 2/3 possibilities and start working on the next till I've resolved the issue, where abouts would the vac pump be fitted on a 110 asv? Hopefully come tomorrow eve il have a sorted car lol I do hope so
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Irratic turbo boost isuue
- Thread starter Grant1985
- Start date
Just a update, I used Mr muscle today in through the exhaust port of the turbo left it for 2hrs and every 10/15min I pushed the actuator seems free enough, fixed the hard brakes it was the vac pipe on the joints, so I used insulation tape as a temp fix with jubilee clips and brakes are perfect now, but I still have the issue with the turbo it hasn't solved the problem or changed in anyway, so what is my next step of action to get it sorted
Sounds like a plan mate 
Have a look at this link, you'll see that the vacuum pump is on the right hand side of the cylinder head on all those models, so i would imagne yours is the same. http://forums.tdiclub.com/showthread.php?t=290286&highlight=vacuum+diagrams
Have a look at this link, you'll see that the vacuum pump is on the right hand side of the cylinder head on all those models, so i would imagne yours is the same. http://forums.tdiclub.com/showthread.php?t=290286&highlight=vacuum+diagrams
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What's vcds? I'm hoping my mates neighbour will plug it in to his vagcom Sunday, but I wouldn't mind doing it before its just money pending at mo, I disconnected the maf the other day and drove it and I had no turbo at all, just turbo less and gutless, so I marine that it isn't a maf, other suspicions are the turbo boost control which I have no idea where that is or how to do a test to see if it works, I've blocked off the egr valve at turbo and plugged the vac pipe, one of the bolts for the egr pipe to egr itself I couldn't get in but if it's blocked and disconnected it shouldn't be to much of a bother should it?
Yeah sorry mate VCDS is just the new name for vagcom. That should throw up some codes as to what is going on. If there are no codes then you can use it to run logs of the engine data as you drive. You'll be able to see what boost the ecu is asking for ,and what boost it is actually getting. Along with being able to see the injection timing etc etc. The boost is group 115 on the petrol cars, no idea if it's the same on the diesels. If not then you can scroll through "measuring blocks" under the engine section until you find the data you're looking for.
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Plugging the EGR pipe with a bolt is one of the EGR fixes I've heard of, but not sure if it's the vac pipe or the actual EGR pipe on the valve that should be blocked. I have the same TDI 110 engine as you and I've unplugged the electrical connector to the EGR vacuum control valve, the car has been running fine like that since 2007.
Have you checked the vac pipe from the N75 valve down to the turbo actuator? The car will try and move the actuator when the revs get close to 3,000 to stop the turbo over speeding. If it can't then you'll get limp mode which only gets reset when you restart the engine.
Getting VCDS/VAGCOM on the car will help, but you will need to know how to read/understand the information. I've only used VCDS to switch on my cruise control so wouldn't know how to diagnose faults with it. But I think you can force the N75 valve to cycle the turbo actuator through VAGCOM, then you can check to see if the car is able to move the actuator.
If you've disconnected the vacuum hose from the top of the EGR valve then you simply need to block it with a bolt or golf tee.
You can leave the metal inlet pipe on the EGR body untouched.
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You can leave the metal inlet pipe on the EGR body untouched.
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Hi chriswales6 il check the n75 vac tomorrow, what is it I'm actually looking for? And what else should just do? I read somewhere about spraying wd40 on there somewhere, not sure if this is right but what shall I test or do to be 100% if it's the n75 or the actuator etc
Hi, I guess wd40 would be sprayed on the actuator rod if it was stuck/rusty but since you've already check the rod moves then you need to look at the system that moves the rod.
Basically the n75 valve opens and pulls a vacuum down the rubber vac pipe to the actuator attached to the turbo. The actuator has a diaphragm which the vacuum pulls against to move the rod. When the n75 valve closes the vacuum is released and rod moves back.
Any of these parts can fail, but its usually the rubber vacuum pipe that goes first. Ideally you'd use a hand vacuum pump to check if the vac pipe and diaphragm in the actuator can hold a vacuum. If you don't have one then have a good look at the vac pipe to see if it's knackered.
I think you maybe able swap the n75 and EGR valves over to see if the problem is with the valve, but I've never tried that myself.
The two vacuum control valves are on the firewall above the engine, the one on the left is for the EGR the one on the right goes to the turbo.
I took a photo of mine this morning but I’m in work and can’t attach it to message. On my car the EGR has a black top the N75 valve has a white top. You’ll need to check the vacuum pipes connected to the N75 valve.
Below is a link to a video that describes what can go wrong with a VNT turbo.
https://www.youtube.com/watch?v=Ppif4qC560U
I took a photo of mine this morning but I’m in work and can’t attach it to message. On my car the EGR has a black top the N75 valve has a white top. You’ll need to check the vacuum pipes connected to the N75 valve.
Below is a link to a video that describes what can go wrong with a VNT turbo.
https://www.youtube.com/watch?v=Ppif4qC560U
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