Revo Stage 2 Mapped But Only Getting 0.8bar Of Boost?

Gaz-M

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My mate has had his car mapped to stage 2 but it isnt making the 1.5bar of boost it should. Its only making 0.8bar.

Fault had came up for n249 valve so bypassed it but still the same.

I temporarily blocked the actuator feed off so it would run full boost and it was better.

What should i check first? Actuator? Whats method of testing?

Cheers.
 
Actuators go soft, always good practice to renew an actuator to an uprated one running that boost.
 
Cheers, i'll do that then. I assume they are fun to change due to location?

Best one to get? How do i go about setting it to run 1.5bar?
 
Scanned for fault codes?... before changing every component you see you should check for fault codes and ideally log boost (block 115) in VCDS to see if its actually requesting 1.5bar...

Revo is switchable and 0.8bar is std boost... if there are no other fault codes then its either been set to std boost somehow or it was a trial flashed by mistake and its now reset to std...

What was the N249 fault and define bypass? people get this round their necks all the time and fault is typically N249 mechanical failure which is not normally a fault with the N249 but its either a faulty DV or the N249 has already been 'deleted'... the fault code appears due to the ECU trying to dump boost (from an over boost condition for example) and it uses the N249 to operate the DV while under boost using vacuum stored in the little black container on the cam cover... the fault pops up when it doesn't see boost drop like it expects due to a faulty DV or because the N249 is no longer connected to the DV

<tuffty/>
 
Cheers, i'll do that then. I assume they are fun to change due to location?

Best one to get? How do i go about setting it to run 1.5bar?

You won't be able to use anything other than a std actuator if you choose to change it as the map won't know anything about it and will constantly overshoot on spool... this will lead to rod bending torque spikes...

The map won't have changed assuming its not a trial and its not been set with and SPS box for std boost...

Actuators do go soft but not 1.5bar to 0.8 bar soft... check boost request vs actual boost with block 115 in VCDS.... another test is to unplug the N75 electrically as this should drop boost to 0.5bar... this would suggest the actuator is fine and its something else...

When you say you blocked off the actuator and it was better... what boost did it get too?

One other thing... what car is it we are talking about? I am assuming its an S3 and have been making my diagnosis based on that

<tuffty/>
 
Tuffty thanks for taking time to go into depth. You are right its an N249 mechanical failure code. This was diagnosed by the tuner who applied the map.

So would you suggest checking dump valve first due to this code?

Its a 2000 S3 210bhp version.
 
Possible that the diverter valve is faulty? Is it OEM or Forge etc etc?
Test to see if the DV is leaking (push the piston up, put a finger over the vac line and see if piston drops ) etc etc
 
The plastic diverter valve? Oem black thing on right hand side of head?

I'll check the DV, is it obvious when there knackered?

Where do i find N75 valve?

Ive just re-read Tufftys advice- we checked actual boost against requested boost and it was very slightly less but nowhere near asking for the 1.5bar.

What would that point towards?
 
Ive just re-read Tufftys advice- we checked actual boost against requested boost and it was very slightly less but nowhere near asking for the 1.5bar.

What would that point towards?

In which case I would take the car back to where you got it mapped and ask why this is... it sounds to me that they flashed a Revo trial and its expired...

<tuffty/>
 
But it has been crap from the minute they loaded the map? Or thought they loaded the map...

He put it in for map, they said they mapped it and it wasnt any quicker so ran fault scan and the n249 mech failure came up. He also said it was only running 0.8bar instead of 1.5bar.

I bypassed n249 and test drove it with live data, it was pretty much matching the requested boost which is about 1800mbar maximum, nearly 1000mbar of that being atmospheric pressure and therefore i was reading the same 0.8bar but it was also requesting maybe 2100mbar at very most?
 
Can it not just be requesting low boost as its in some kind of safe mode?

Dont want to go back to tuner blaming them unless i know for sure it should be requesting full boost.

So it should be requesting around 2500mbar if the map is on and okay?

What are other options, DV or N75? Since actuator cant go as bad as drop that amount of boost, and the tuner checks MAF, knock etc readings before/ after mapping..
 
if its in limp mode a fault code clear would clear it..
I dont think thats your issue

What sps settings are in it?

What actual request do you see? block 115

log it and post results for more info/advise
 
Limp mode is actuator pressure... it turns off the N75 control when in limp mode which is 0.5bar...

Either way the car left the tuners not being right... they have a duty to ensure you get what you pay for... if they are using the N249 as an excuse then they probably shouldn't be allowed to map cars in the first place

You don't have to blame them for anything... I assume the N249 fault hasn't come back? was this a flash and go tuner or did it get run on the dyno?

Have you any proof it was running mapped boost after it was flashed?

<tuffty/>
 
So the fact its running 0.8 (standard) not 0.5 (limp) or 1.5 (stage 2) looks like its the map at fault?

It was mapped, charged for the map and told it isnt running any quicker or the right power due to another fault. Ran a scan and the N249 was noted.

They dont have a 4wd dyno so couldnt run it on that, but obviously a Revo is a generic map anyway- or as good as.

Could the N249 simply not cause this fault?
 
if its in limp mode a fault code clear would clear it..
I dont think thats your issue

What sps settings are in it?

What actual request do you see? block 115

log it and post results for more info/advise

No i now agree its not in limp state.

Request from memory was maybe an absolute maximum of 2100mbar and dropping to 1800mbar after boost spike.

It was always near enough matching the requested boost, as youd expect.

I only have use of Snap On which shows live data.
 
So the fact its running 0.8 (standard) not 0.5 (limp) or 1.5 (stage 2) looks like its the map at fault?

It was mapped, charged for the map and told it isnt running any quicker or the right power due to another fault. Ran a scan and the N249 was noted.

They dont have a 4wd dyno so couldnt run it on that, but obviously a Revo is a generic map anyway- or as good as.

Could the N249 simply not cause this fault?

The can run an S3 on a 2WD dyno... you pull the fuse... guess they don't do much in the way of VAG stuff then... sounds like they are taking you for a ride tbh mate

<tuffty/>
 
Ye I would take it back and ask them to remove the map and reinstall. where did you get it done?

mark
 
ps do you have the other bits and bobs on that are required to go up to stage 2 map?
 
So the fact its running 0.8 (standard) not 0.5 (limp) or 1.5 (stage 2) looks like its the map at fault?

It was mapped, charged for the map and told it isnt running any quicker or the right power due to another fault. Ran a scan and the N249 was noted.

They dont have a 4wd dyno so couldnt run it on that, but obviously a Revo is a generic map anyway- or as good as.

Could the N249 simply not cause this fault?
fuse 31 disables haldex so 2wd dyno can be used.
there may be an issue, who knows from reading words on a pc screen off a forum, BUT, it looks likely there's something else "not limp mode, not n249" related

If you have a reputable vag specialist near you I would seek them out, and get a smoke leak test done, some logging of parameters and confirm what SPS settings were put onto your revo map.

logging 115 live data for request vs actual next to 118 actual n75 duty cycle would confirm if request is not being achieved because of N75 max'd out on its duty cycle (>95%) or the request is just low.

VCDS is your friend if you want to save some diagnostic pennies with garages and you plan to keep your vag car
 
Ok i have to apologise, we just went out for a run in it and it is requesting 1.5bar after all, actual boost of not even 0.8bar.

Also shows wastegate duty cycle, i assume thats the N75 requests?

DV diaphragm is okay, whats easiest way to check if spring in it is soft and allowing it to leak boost? I can quite easily open it with my finger.

55f05aa70c7fbaf27e408babd757c8a7.jpg
 
Also, cleared codes before run, now it has the N249 mechanical malfunction code back!
 
What do you mean doing 100% N75? I assume the readings are it opening and closing the N75 which in turn opens actuator/ wastegate? Is the actions on it normal?
 
to achieve boost a duty cycle is applied to the n75.. Its max will be 95% or more.. If thats what its doing, and not achieving a sensible requested boost it indicates there is something tired..... such that the turbo cannot spool fast enough to sustain said boost.

so if n75 is 95%-100% there's nothing more to be had boost wise, without investigating why

Was it ever running higher boost? or is this map new to you and you were std before hand?
 
I dont understand the working of the N75, i assumed it would simply get a signal from ECU at a set boost pressure to open the wastegate to stop spooling?

Its not my car but im sure it was Stage 2 a while ago as it had everything on it to be stage 2, but had cat pipe replaced for standard and standard map on it. Now we fitted decat downpipe and software put on- it was no quicker, tuner told us N249 fault logged and told us it needed fixed and car would run as it should.
 
N75 opens and closes at a speed thus regulating the boost pressure to the actuator... its a solenoid at the end of the day and is normally open so all boost pressure gets to the actuator... once the actuator sees enough pressure to open it fully (at its rated pressure of 0.5bar in this case) then thats essentially where the boost sits... the N75 interrupts this thus allowing less pressure to reach the actuator so it doesn't open as much... this allows the turbo to generate more boost

Thats essentially it... it gets more complicated when we get into load profiles, cylinder fill and other stuff as you don't actually tell these ECU's what boost you want as they are load based... boost is a facilitator... the ECU has a load profile it follows to work out how much air to obtain to meet the drivers requested throttle input... it will ask for more or less boost depending on all sorts of variables like atmospheric pressure, intake air temps etc :)

<tuffty/>
 
So you paid for a "tuner" to map your car, now Bill is having to spoon feed you on how to fix it. For free.

I lol'd till the lol's came home.

Why not just take it to a PROPER VAG specialist, have the crap Revo map taken off and get it properly fault tested, properly dyno'd and properly mapped by somebody that knows what they're doing?

Sorry if that's already been said...
 
So you paid for a "tuner" to map your car, now Bill is having to spoon feed you on how to fix it. For free.

I lol'd till the lol's came home.

Why not just take it to a PROPER VAG specialist, have the **** Revo map taken off and get it properly fault tested, properly dyno'd and properly mapped by somebody that knows what they're doing?

Sorry if that's already been said...

Why not save your breathe if youve nothing helpful to add.

If the forum was full of people like you it wouldnt exist.

Some of us like to understand and fix our own cars, and dont have limitless funds to hand it into a garage to fix.

They were paid to install a map, which theyve done.

Your post is utter pointless, please stay out my thread.
 
Again Tuffty, thanks for your extensive input.

Just shows the opposite ends of the scale in here. How to be helpful and make friends like forums are designed, and then how to be disliked and ruin them.

Anyway, im now fully understanding the N75, again thanks to you.

So the fact its at 100% duty means its basically allowing no boost pressure through it, in turn keeping the actuator from opening the wastegate to try and make boost, but its still not making the requested boost?
 
Oh this is going to start A war. You have to laugh at jardos comments not argue. Plus he has a lot of experience with tuners. I know where I'm going when it comes to my tuning Badger5 and I live in Guernsey so not a half hour drive. You get what you pay for with things like this. Luckily people on here are willing to help you so don't burn your bridges
 
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Burn my bridges? Okay.. As you can read above ive been very thankful to those who are helping.

PLEASE DO NOT FILL THIS FULL OF POINTLESS POSTS !!
 
Sorry, I'm staying now just for fun.

You say you like to understand and fix your cars, and that's great. Don't we all. But what's this got to do with your mate getting his car mapped and the tuner not doing a very good job?

Do you think I have limitless funds? I don't I promise you. Which is why I don't waste money, and make sure everything I do is done properly. And I guess I just feel bad for your mate because he's spent money on a remap, when any reputable company would have thoroughly fault checked the cars hardware, and if there were hardware issues notified him before they did the work and probably turned him away and told you to come back when it was ready for further tuning...or fixed it for him.

It's no good doing a job and then saying "oh by the way, you won't be able to make use of it because along the way I found something that was causing an issue but I ignored it."

But if your mate had of read some of the information that I have spent hours of my life writing for the stickies on this wonderful forum that I'm wrecking then he would have fault checked the car thoroughly before presenting it for mapping. And hopefully taken it to a more reputable tuner.

He's paid a company for a service, if the car isn't running right then surely he should be taking the car to the tuner who mapped it and be working with them to sort it out...If not the very first thing I would do is take the car back, say the service they have given is crap and that if they don't refund the software and revert to stock you will report them to Revo.

Then use the money to get the car in a presentable state before taking it to a more reputable tuner.

Anyway, to try and be of some help.

You've worked out that the engine is requesting "stage 2" boost, so now you need to work out why it isn't delivering it.

You need to log the duty cycle of the N75 valve as said, and see if it is functioning correctly.

If it is you need to work out why there is no boost (actuator is the best place to start) or where the boost is being lost (boost leaks, generally everywhere.)

Have you done any form of pressure/smoke test on it?
 
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Yeah I saw that but jardo is just winding you up. That's what he does. A lot of people like him and if you start arguing with him people might stop helping soo much. I'm interested to see what it is causing the problem. Hope you get it sorted soon.
 
I doubt they will Nick. Nobody has my back these days, apparently I'm too much of a know it all **** :meeting:
 
First sentence on the Revo site technical support page...

"Given the age of most vehicles with the 1.8T engine it is important for the vehicle to be 100% healthy before having any performance software installed. If your vehicle has any running issues in standard form our dealers will be able advice on how to proceed with rectifying issues. Any running issue needs to be resolved before the vehicle can be upgraded."

http://www.revotechnik.com/support/technical/18t-engine-notes
 
If you're going to be backward and not take it right back to the tuner....start with what you DO know, you know there is an N249 fault. Find the source of that for a start. A search will reveal exactly what that valve is/does and how its configured. You find the source of that fault and you're on track to sorting the issue. If it doesn't behave once that's started, then you can go from there, and will be forced to get vcds to help you.
 
Thats more like the spirit! ;)

Interesting the quote youve put up, never thought about it that way.

I think we just assumed it was a simple enough job for them. once it was mapped and told it needed a boost issue fixed before it would run stage 2 boost, we were more inclined to find the fault so it runs as it should rather than think of someone to blame.

Wont get a chance to look at it again until next week now, but will see what i can narrow it down to with help received.

Thanks.
 
If you're going to be backward and not take it right back to the tuner....start with what you DO know, you know there is an N249 fault. Find the source of that for a start. A search will reveal exactly what that valve is/does and how its configured. You find the source of that fault and you're on track to sorting the issue. If it doesn't behave once that's started, then you can go from there, and will be forced to get vcds to help you.

Yeh looked into that, its an ecu controlled vacuum to open the DV, although im not entirely sure what could give the fault code. Id guess its when it feeds the N249 to bleed off some boost but then sees no boost drop ?

Checked vacuum side of DV thats okay.
 

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