Requested boost vrs actual boost

[TrevorB33]

The 17705 code is a common occurrence on older remaps, most of the newer ones code round the issue, it's a known problem, have a search, if no leaks then its the map

[BrownBarge]

Wonder where other forums are getting 9psi from. 0.7 bar is 10.1psi - that's a 10% discrepancy in values which is pretty big

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The 1.8 comes in many different forms so boost probably does vary in some degree throughout the range

[David 8]

I've had a look at the logs but you need a good few 3rd gear runs from low rpm up to redline 

 

Do block 1+2+115 for fuelling and boost 

 

Then 1+20 so we can see what your timing is doing 

 

 

On your private test track of course ... 

[David 8]

Standard boost does vary at "around" 9-10psi

 

+1 on what Trevor said regarding the older maps.

[BrownBarge]

So if mine is suspected of having a map then how would i tell if iv got a turbo failing of a map problem. My requested acording to vagcom is around 2000 mbar and when it goes into a safe mode the actual never goes above 1350 mbar but after i switch of and back on my actual will be anything from 1900 to 2200 mbar buts its boosting intermittently, sometimes kicking in late at around 3000 revs but always dhows up the 17705 code even after clearing it after the car has been left to cool down all it takes is a start and a rev up and the codes right back again. I just dont know whats causing the intermittent boosting when its boosting and also why it keeps going into a safe non boost mode after its been sat a while. And now stuck between a possible failing turbo or dodgy map but brought it on the assumption of it being stock and never messed with.

Personally it needs smoke testing otherwise you could just be chasing problems that dont exist i.e your map.

If you cant find someone to smoke test near you then buy some choke & carb cleaner from the quid shop(blue & white tin) remove all the engine covers and spray the cleaner on all the breather pipes most problematic ones are under the inlet manifold and in that area. For the sake of a quid & 10mins its worth doing. Youll no if the carb cleaner ends up in the inlet as the car will start to choke itself

[Nerd]

Run a logged pull, check for surges - sounds like a buggered actuator

And those levels are or AUQ engines. Where's your definitive level coming from? Few places quote 9, only you're quoting 10. I like to get the correct information on these things

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[Watto]

Just an update. 4 cans of carb cleaner has been sprayed over all nessery pipes, throttle body gasket, ait sensor, intake manifold gasket, injectors, around coil packs, IC everywhere and ingine idle never changes.

Iv rang Rtek and had a chat and they said it sounds like ecu problems, so going to book it in and see how it goes.

[Nerd]

Let us know what they say

[Watto]

There going to run a full diagnostic on a rolling road, pressure and smoke test and hunt down whats causing the problem and will also find out if it had been mapped by the previous owner. They even said it could still be the ecu even if its never been mapped but hopefully Ill come away knowing what the cause is weather it be turbo related, hidden leak, or ecu. Ill report back my findings its in in just over a week.

[Nerd]

To me it sounds like your Actuator or n75 but should throw a different error code. Be nice to figure it out so you can sleep at night ;-)

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[Watto]

As for the boost levels A friend is a mechanic, 30 years in the trade and even he's a little stumbled but said if it had been mapped it would explain why we cant find the problem. He was reluctant to change anything as he had tested them and found to be working but I changed the parts anyway for my piece of mind. He found on the pc with the skoda manual and it said requested boost is 1800 mbar and after the calculations of atmospheric pressure it equals around 11psi and everyone iv asked on forums say stick should be around 10-13 psi. We did a quick log in the requested and actual with vagcom and its requesting around 2000-2200 mbar witch equals to 17 psi making me think mine has been mapped. But im not 100% on what the stock levels are for a mk1 occy vrs. Rtek even said if its requesting around 2000 mbar its likely to be mapped

[Nerd]

That's one of the things they map is requested boost, it should not request any higher values than is specified in the factory map unless of course some novice tuner got his mits on it and cocked up the map.

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[Watto]

Stock not stick* :/ if it is the actuator hopefully they will be able spot it on the rolling road. It has been tested with a mechanical pressure pump and seems to be opening and closing as it should but dont know if the actuator has been messed with so again hopefully this diagnostic will find it and ill sleep for a week

[Nerd]

I'm sure they'll sort it out and get it boosting again properly

[David 8]

As for the boost levels A friend is a mechanic, 30 years in the trade and even he's a little stumbled but said if it had been mapped it would explain why we cant find the problem. He was reluctant to change anything as he had tested them and found to be working but I changed the parts anyway for my piece of mind. He found on the pc with the skoda manual and it said requested boost is 1800 mbar and after the calculations of atmospheric pressure it equals around 11psi and everyone iv asked on forums say stick should be around 10-13 psi. We did a quick log in the requested and actual with vagcom and its requesting around 2000-2200 mbar witch equals to 17 psi making me think mine has been mapped. But im not 100% on what the stock levels are for a mk1 occy vrs. Rtek even said if its requesting around 2000 mbar its likely to be mapped

 

 

Stock is 9-10, it may go a little higher on a hot day to allow for timing pull but 13 is way over, and being mapped would have nothing to do with diagnosing the problem. 

 

 

That's one of the things they map is requested boost, it should not request any higher values than is specified in the factory map unless of course some novice tuner got his mits on it and cocked up the map.

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It could do, if theres a big hole somewhere, the ecu could be trying to compensate by pushing more air in, my guess is its mapped though.

 

 

[Nerd]

That's why I'm guessing the Actuator or n75 is at fault and not closing the wastegate fully giving big discrepancies on requested and actual. A leak that big you'd hear unless maybe an intercooler core is ruptured but then again you'd see a tiny spattering of oil round the rupture.

Do you want me to do a thread count on my Actuator arm so you can check yours is set ok?

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[David 8]

 

 

This is a quick plot dug out from what you sent me, as you can see your ok up to 3k then the spec is way higher, I notice your N75 duty cycle looks low but I'm not entirely sure on what that should be doing. I'm sure it should be higher than 5.1 % though.

 

I'll take another dig in the files now.

[Nerd]

That's a major problem right there- max 5% duty cycle at 100% load means the wastegate is almost fully open across the range- Bad N75 is first guess at those readings

[David 8]

That's a major problem right there- max 5% duty cycle at 100% load means the wastegate is almost fully open across the range- Bad N75 is first guess at those readings

 

 

That sounds about right I could remember which way round the reading went on the N75 

[Nerd]

In the low ranges it should be basically 100% meaning the gate is totally closed then slowly fall as it's at max boost and the gate needs to open to regulate the boost so the N75 seems to be goosed

[Watto]

The N75 has been replaced with a new oem one. so not sure whats going on if its reading low. Hopefully they should spot all that on the rolling road diagnostics. You could give a thread count but I would of thought no two are the same but could also give me an indication if mine is way of.

[Nerd]

same actuator on the same turbo should be set almost identically from the factory unless someone;s been trying to tighten it and hasn't locked the nuts properly and they've worked loose

[Watto]

The second log has totally different readings. That log is when it was in the limp mode.

[Nerd]

In Theory limp mode should be the n75 allowing the gate to fully open

 

Here's where mine's set and I haven't tightened it yet so should be at stock turns. Didn't count the threads but you can from the pic

 

[Watto]

Cheers ill check that tomorrow i wont be able to concentrate in the rain.