Turbo Flutter/Surge off throttle - DV solenoid?

[muff1991]

thanks for your input pudding... I'm in the process of building a Boost leak tester, so ill check for boost leaks for sure and then @Dave aka got a spare N75 valve so I'm going to rule that out too as read online it could be that. cheers

[pudding]

A cheap mechanical gauge gaffer taped to the windscreen is a sound idea 

[muff1991]

I'm on it.. .cheers Pudding :)

[pudding]

Mechanical is better as you can see the boost fluctuations easier.  Digital gauges are just numbers flying around.  Can't beat an old school pointer!  Where are you based?

[muff1991]

Mechanical is better as you can see the boost fluctuations easier.  Digital gauges are just numbers flying around.  Can't beat an old school pointer!  Where are you based?

I’m based in Berkshire & Buckinghamshire you?
Totally agree, don’t like the digital at all!! I ordered a cheap sweeper... comes with hose and all that just need to get a T-piece


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[Dave aka]

I’m convinced my cam chain cover gasket is leaking and I know where from, that one t30 bolt at 6 o’clock on the cam chain cover, gonna take the vacuum pump off and pinch all the bolts up again as I’m sure the bottom ones gonna be semi loose (hate tightening in to alloy) gonna see if that’s why my cam position sensor has oil on it from time to time but I can clearly see a leak now.......if this don’t work.......I will replace the engine


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[pudding]

Mechanical is better as you can see the boost fluctuations easier.  Digital gauges are just numbers flying around.  Can't beat an old school pointer!  Where are you based?

I’m based in Berkshire & Buckinghamshire you?
Totally agree, don’t like the digital at all!! I ordered a cheap sweeper... comes with hose and all that just need to get a T-piece

I'm miles away, in Suffolk.  I was going to have a listen to your car and scan it if you were local!

[muff1991]

Mechanical is better as you can see the boost fluctuations easier.  Digital gauges are just numbers flying around.  Can't beat an old school pointer!  Where are you based?

I’m based in Berkshire & Buckinghamshire you?
Totally agree, don’t like the digital at all!! I ordered a cheap sweeper... comes with hose and all that just need to get a T-piece

I'm miles away, in Suffolk.  I was going to have a listen to your car and scan it if you were local!

Proper shame pudding, thanks very much for the offer though. I wish you could hear it in person just to understand me more as the sound clip really doesn’t do it justice. I’ll lay money on it being abnormal lol. The more I think about it, the more it just seems like the air isn’t diverting (when coming off throttle) I have all sorts of bits to try this weekend if it ain’t raining . But will report back with good or bad news. Cheers.


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[pudding]

Good luck mate!  If the air isn't being dumped at all, or only partially, the Mr Turbo won't like it and make all sorts of noises!

[muff1991]

so i run into a little trouble over the weekend...

firstly I done a boost leak test: removed the rear pcv hose and bunged it... took CAI off and inserted my boost leak tester pre turbo... with the gauge from my tyre pump it was hardly giving me a reading of around 10 psi I had to really leave it pumping for a while to build pressure and I mean ages!
I have temporarily fitted a PCV delete at the front (process of elimination), so the intake manifold has the little metal bung on (held on with a clip) and this was leaking a tiny bit of air... so maybe that's why it was struggling to rise in pressure. I will sort that out!
But... I also run my "cheap mechanical gauge" off a nipple on this bung and when I got the pump gauge up to 20psi this gauge off manifold read around 10-12psi, I could not work this one out! one of those gauges has to be wrong.. or I am doing something wrong!
I could also hear loads of oil gurgling and dripping within the engine (oil cap was removed) I'm still waiting on my pressure gauge to arrive so I can fit to my boost leak tester so will do this again and sort that first leak out. Pressure really had to try to build unlike when I pump tires lol now I'm not sure if this is a good thing as in... am I on route to the cause of my issue here, or is the DV blocking off... allowing the nearest gauge to read 20psi and the furthest on the opposite end of the system to read 10psi.

I needed the ignition on in order to use the tyre pump so not sure if that hasn't helped and making the DV shut but then it should be released right.

also wondering - does anyone know if the Diverter Valve can be turned off using VCDS as I know a few features have been played around with by previous owner?
 
absolutely kicking myself too... when I was fitting the rear pcv hose (was a pig and I've had it on and off before!!) I bloody snapped the little rear hose nipple next to it  luckily @Dave aka has got his spare cover for me, so ill get all that sorted later this week!

[pudding]

So you were pumping air into the engine to see if it held pressure?  A bit like a cylinder compression test?  I don't think you will get it to hold a pressure like that as the air path is huge, plus open valves, turbo and intercooler to fill etc etc.

You can use the mechanical boost gauge on the PCV delete nipple though     If you're looking for vac leaks, a smoke tester is best.  At a really cheap basic level, simply blow lots of cigar smoke into the turbo intake hose    Or you can fairly cheap proper testers these days.....I think. Haven't looked in a while.

You can't disable any engine functions with VCDS.  You need to hack into the ECU software to do that.  If you're looking for DV solenoid activity, you could wire up a 12V LED across the 2 pins and tape it to the windscreen?  Lol, you'll have so much stuff taped to the screen you won't be able to see through it at this rate 

[muff1991]

So you were pumping air into the engine to see if it held pressure?  A bit like a cylinder compression test?  I don't think you will get it to hold a pressure like that as the air path is huge, plus open valves, turbo and intercooler to fill etc etc.

You can use the mechanical boost gauge on the PCV delete nipple though     If you're looking for vac leaks, a smoke tester is best.  At a really cheap basic level, simply blow lots of cigar smoke into the turbo intake hose    Or you can fairly cheap proper testers these days.....I think. Haven't looked in a while.

You can't disable any engine functions with VCDS.  You need to hack into the ECU software to do that.  If you're looking for DV solenoid activity, you could wire up a 12V LED across the 2 pins and tape it to the windscreen?  Lol, you'll have so much stuff taped to the screen you won't be able to see through it at this rate 

Pudding... I can’t read more than 2-3 post of yours without coming across one that cracks me up! The 12v LED is a good idea! Good thinking! I disconnected my DV and took the car for a drive... the throttle response was a bit rubbish as expected. But the flutter sounds wasn’t hardly any worse! It was a liiittle bit worse but not that bad!

I was trying to do a boost leak test... so I pushed air from the turbo inlet all round the charge air system into the inlet manifold. Found a small leak on the inlet manifold where the pcv block  off bit plugs onto. But couldn’t find anything else. And yes because the valves and stuff were open the air was probably going straight through... next time I do it, I’m going to take the throttle body pipe off and block it. So there’s only start to finish from the turbo inlet to the TB inlet.

I’m mainly trying to test for vac leaks and boost leaks... also wanted to see/hear if there was any air coming out the N75 valve hoses. As I’m convinced all these issues I’m having has something to do with it.

As mentioned in my other post... I’m planning on getting vcds next month. So will knock on you all on how to use it properly haha. But hopefully it might point me in the right direction.

Cheers


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[pudding]

So you were pumping air into the engine to see if it held pressure?  A bit like a cylinder compression test?  I don't think you will get it to hold a pressure like that as the air path is huge, plus open valves, turbo and intercooler to fill etc etc.

You can use the mechanical boost gauge on the PCV delete nipple though     If you're looking for vac leaks, a smoke tester is best.  At a really cheap basic level, simply blow lots of cigar smoke into the turbo intake hose    Or you can fairly cheap proper testers these days.....I think. Haven't looked in a while.

You can't disable any engine functions with VCDS.  You need to hack into the ECU software to do that.  If you're looking for DV solenoid activity, you could wire up a 12V LED across the 2 pins and tape it to the windscreen?  Lol, you'll have so much stuff taped to the screen you won't be able to see through it at this rate 

Pudding... I can’t read more than 2-3 post of yours without coming across one that cracks me up! The 12v LED is a good idea! Good thinking! I disconnected my DV and took the car for a drive... the throttle response was a bit rubbish as expected. But the flutter sounds wasn’t hardly any worse! It was a liiittle bit worse but not that bad!

I was trying to do a boost leak test... so I pushed air from the turbo inlet all round the charge air system into the inlet manifold. Found a small leak on the inlet manifold where the pcv block  off bit plugs onto. But couldn’t find anything else. And yes because the valves and stuff were open the air was probably going straight through... next time I do it, I’m going to take the throttle body pipe off and block it. So there’s only start to finish from the turbo inlet to the TB inlet.

I’m mainly trying to test for vac leaks and boost leaks... also wanted to see/hear if there was any air coming out the N75 valve hoses. As I’m convinced all these issues I’m having has something to do with it.

As mentioned in my other post... I’m planning on getting vcds next month. So will knock on you all on how to use it properly haha. But hopefully it might point me in the right direction.

Cheers


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Yeah I'm a crazy fool    Is it an OEM DV you're using? Rev G?  You could try disconnecting the N75 and see if you get spring pressure boost, which is about 8psi iirc.  If you reconnect it and get more boost, the N75 is fine    VCDS is king!  You can only get so fat without it 

[muff1991]

So you were pumping air into the engine to see if it held pressure?  A bit like a cylinder compression test?  I don't think you will get it to hold a pressure like that as the air path is huge, plus open valves, turbo and intercooler to fill etc etc.

You can use the mechanical boost gauge on the PCV delete nipple though     If you're looking for vac leaks, a smoke tester is best.  At a really cheap basic level, simply blow lots of cigar smoke into the turbo intake hose    Or you can fairly cheap proper testers these days.....I think. Haven't looked in a while.

You can't disable any engine functions with VCDS.  You need to hack into the ECU software to do that.  If you're looking for DV solenoid activity, you could wire up a 12V LED across the 2 pins and tape it to the windscreen?  Lol, you'll have so much stuff taped to the screen you won't be able to see through it at this rate 

Pudding... I can’t read more than 2-3 post of yours without coming across one that cracks me up! The 12v LED is a good idea! Good thinking! I disconnected my DV and took the car for a drive... the throttle response was a bit rubbish as expected. But the flutter sounds wasn’t hardly any worse! It was a liiittle bit worse but not that bad!

I was trying to do a boost leak test... so I pushed air from the turbo inlet all round the charge air system into the inlet manifold. Found a small leak on the inlet manifold where the pcv block  off bit plugs onto. But couldn’t find anything else. And yes because the valves and stuff were open the air was probably going straight through... next time I do it, I’m going to take the throttle body pipe off and block it. So there’s only start to finish from the turbo inlet to the TB inlet.

I’m mainly trying to test for vac leaks and boost leaks... also wanted to see/hear if there was any air coming out the N75 valve hoses. As I’m convinced all these issues I’m having has something to do with it.

As mentioned in my other post... I’m planning on getting vcds next month. So will knock on you all on how to use it properly haha. But hopefully it might point me in the right direction.

Cheers


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Yeah I'm a crazy fool    Is it an OEM DV you're using? Rev G?  You could try disconnecting the N75 and see if you get spring pressure boost, which is about 8psi iirc.  If you reconnect it and get more boost, the N75 is fine    VCDS is king!  You can only get so fat without it 

Thanks for the tips mate, 100% getting genuine vcds end of jan. But I’ll defo give the N75 valve a play with! I have got a new one to fit but looks a right pig and some hours worth of work I ain’t got at the mo. Lol


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[muff1991]

So you were pumping air into the engine to see if it held pressure?  A bit like a cylinder compression test?  I don't think you will get it to hold a pressure like that as the air path is huge, plus open valves, turbo and intercooler to fill etc etc.

You can use the mechanical boost gauge on the PCV delete nipple though     If you're looking for vac leaks, a smoke tester is best.  At a really cheap basic level, simply blow lots of cigar smoke into the turbo intake hose    Or you can fairly cheap proper testers these days.....I think. Haven't looked in a while.

You can't disable any engine functions with VCDS.  You need to hack into the ECU software to do that.  If you're looking for DV solenoid activity, you could wire up a 12V LED across the 2 pins and tape it to the windscreen?  Lol, you'll have so much stuff taped to the screen you won't be able to see through it at this rate 

Pudding... I can’t read more than 2-3 post of yours without coming across one that cracks me up! The 12v LED is a good idea! Good thinking! I disconnected my DV and took the car for a drive... the throttle response was a bit rubbish as expected. But the flutter sounds wasn’t hardly any worse! It was a liiittle bit worse but not that bad!

I was trying to do a boost leak test... so I pushed air from the turbo inlet all round the charge air system into the inlet manifold. Found a small leak on the inlet manifold where the pcv block  off bit plugs onto. But couldn’t find anything else. And yes because the valves and stuff were open the air was probably going straight through... next time I do it, I’m going to take the throttle body pipe off and block it. So there’s only start to finish from the turbo inlet to the TB inlet.

I’m mainly trying to test for vac leaks and boost leaks... also wanted to see/hear if there was any air coming out the N75 valve hoses. As I’m convinced all these issues I’m having has something to do with it.

As mentioned in my other post... I’m planning on getting vcds next month. So will knock on you all on how to use it properly haha. But hopefully it might point me in the right direction.

Cheers


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Yeah I'm a crazy fool    Is it an OEM DV you're using? Rev G?  You could try disconnecting the N75 and see if you get spring pressure boost, which is about 8psi iirc.  If you reconnect it and get more boost, the N75 is fine    VCDS is king!  You can only get so fat without it 

Thanks for the tips mate, 100% getting genuine vcds end of jan. But I’ll defo give the N75 valve a play with! I have got a new one to fit but looks a right pig and some hours worth of work I ain’t got at the mo. Lol


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And yes, replaced with a new genuine Rev G


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