Hesistation on part throttle...

[Mr OCD]

Yep, turbo should be in around 2500rpm not 4000rpm

Sorry ... it does come in at 2500rpm but then seems to 'stall' and come back in hard at 4000rpm?

 

[traumapat]

Sorry ... it does come in at 2500rpm but then seems to 'stall' and come back in hard at 4000rpm?

starting to sound like something else now. there should be no hesitation on full throttle .

has this coming in a 4k started happening since your new maf went on?

 

[Mr OCD]

starting to sound like something else now. there should be no hesitation on full throttle .

has this coming in a 4k started happening since your new maf went on?

There isnt any hesistation on WOT... just on partial throttle again...

Its like the turbo comes in then decides to stop working then comes in again... if it wasnt electronically controlled I'd say the actuator / wastegate wasnt working properly.

Considering buying an N75 but not sure what part number I need and whether GSF will sell it?

 

[xd-data-ii]

Don't think there is a part number. Just ask them
And better off going for the F (standard) version - not the J

Sounds like it may be this thats the problem

Btw, what fuel are you using and was the map tuned for higher octane fuel?

 

[Mr OCD]

Don't think there is a part number. Just ask them
And better off going for the F (standard) version - not the J

Sounds like it may be this thats the problem

Btw, what fuel are you using and was the map tuned for higher octane fuel?

Whats the difference between F / J versions?

Fuel is Shell V power... no idea if the map was for higher octane...

 

[Mr OCD]

So do we agree next step is to replace the N75?

I'm looking into buying VAGCOM but not sure what I need yet for my 2002 LC...

 

[Mr OCD]

Just been reading up on N249 removal - anyone done this and noticed a difference?

 

[Mr OCD]

Bumpy... dont want to start a new thread on N249 removal and the search shows hundreds of threads!!!

I'm seriously considering replacing the N75 and the dump valve for the sake of it and removing the N249 from the circuit.

 

[munkimafia]

Let me know how you get on. After an initial state of happiness due to smooth running, i have returend to juddery acceleration through 2nd, where power drops off. Have been told to look at the dump valve, but not sure about that either.
having it serviced and cam belt done in a fortnight, goging to wait and see until after that i think.

 

[Mr OCD]

Have a read of this ...
http://www.seatcupra.net/forums/showthread.php?t=112856&highlight=n249&page=1

 

[Mr OCD]

Ok tonight:

- the engine covers are coming off for full removal and inspection of all vacuum hoses
- spark plug gaps are being set to 0.7mm

Friday:

Its going on the rolling road to ensure no issues with the fuelling

 

[Mr OCD]

Just found fault codes from before remap...

I made a note of them before the remap and have just located them so thought would post up as the symptoms were evident prior to the remap...

17705/P1297/004759 - Pressure Drop between Turbo and Throttle Valve (check D.V.!)
Possible Symptoms
Power Loss
Possible Causes
Leaking hoses and/or pipes between components
Check Boost Pressure Control Valve (N249)
Possible Solutions
Check hoses and/or pipes between components
Check / Replace Boost Pressure Control Valve (N249)
Check / clean Throttle Valve, do Throttle Body Alignment
Special Notes
Did anyone fitted an extra (wrong) dump valve?
Retrieved from "http://wiki.ross-tech.com/index.php/17705/P1297/004759"

17545/P1137/004407 - Fuel Trim: Bank 1 (Add): System too Rich
Possible Symptoms
Malfunction Indicator Light (MIL) active
Possible Causes
Mass Air Flow (MAF) Sensor faulty
Fuel Pressure Regulator faulty
Fuel Injector(s) faulty
Oxygen Sensor Control faulty
Oxygen Sensor(s) faulty
Evaporative Emission (EVAP) System faulty
Possible Solutions
Check Mass Air Flow (MAF) Sensor
Check Fuel Pressure Regulator
Check Fuel Injector(s)
Check Oxygen Sensor Control
Check Oxygen Sensor(s)
Check Evaporative Emission (EVAP) System
Special Notes
Fuel Trim Information
Retrieved from "http://wiki.ross-tech.com/index.php/17545/P1137/004407"

I also had:
P1539 - Clutch switch signal improbable - not listed on ross tech

All these faults were cleared after remap and havent been seen since - worth reading into it a little?

 

[Mr OCD]

Feels like I'm talking to myself now

Plugs checked and gaps fine...

Vacuum hoses all checked carefully and no problems found... started engine and sprayed water on all hose joints to see if any leaks - no problems.

Checked pipe that goes round to actuator... again no problems... also checked the actuator ... its firm but I can pull the actuator rod to open the wastegate by hand - is this correct?

Both the bosch dump valve and N75 look like originals... as does the N249...

So what next then?

Picking up VAGCOM lead tommorrow night and will download the freeware version to have a look around.

 

[traumapat]

QUOTE=Mr OCD;1948402]Feels like I'm talking to myself now

Plugs checked and gaps fine...

Vacuum hoses all checked carefully and no problems found... started engine and sprayed water on all hose joints to see if any leaks - no problems.

Checked pipe that goes round to actuator... again no problems... also checked the actuator ... its firm but I can pull the actuator rod to open the wastegate by hand - is this correct?

Both the bosch dump valve and N75 look like originals... as does the N249...

So what next then?

Picking up VAGCOM lead tommorrow night and will download the freeware version to have a look around.[/QUOTE]






where do you live? if your local take me out for a spin and if it does what mine does it might put your mind at rest. i think that a momentary flat spot on part throttle is normal in many leons.
to summerise

at around 3k revs (remember my turbo clicks in after yours) on part throttle i occasionly get a flat spot, similar to a jolt but passengers do not feel it. the revs dont drop...or increase. nor does speed.

nobody has given me a reason for it. and ive asked on here and at jabbasport.

my theory is that the 20vt uses the turbo to accellerate. on part throttle the turbo starts to spin up and starts powering the engine when it suddendly its reached the amount of power required and pulls the turbo out. now youve a straight 1.8 engine haveing to push the turbo as opposed to being powered by it. the effect is a flat spot felt because its right at the point the turbo begins to benefit /or be a drag. by remapping your creating a bigger gap in the power/drag factor of the turbo. it dosnt happen when your part throttling at 4,5,6k revs as the turbos spinning fast enough not to add drag to the engine.

total guess.. but i think its close

 

[Ruddmeister]

my theory is that the 20vt uses the turbo to accellerate. on part throttle the turbo starts to spin up and starts powering the engine when it suddendly its reached the amount of power required and pulls the turbo out. now youve a straight 1.8 engine haveing to push the turbo as opposed to being powered by it. the effect is a flat spot felt because its right at the point the turbo begins to benefit /or be a drag. by remapping your creating a bigger gap in the power/drag factor of the turbo. it dosnt happen when your part throttling at 4,5,6k revs as the turbos spinning fast enough not to add drag to the engine.

total guess.. but i think its close

I have always put this hesitation (on both my Leons) down to the DBW throttle.....

I've had it before where I boot the car away from a junction, then have to back off the throttle and you get a scary moment where the car seems to still be accelerating with your foot off the power. Probably only a split second but scary. Maybe this isn't connected with the hesitation

OCD - have you tried the obvious Throttle body realignment (VAG-COM and key in ignition) assume you have.......best to start with the cheap options when using trial and error to diagnose a fault ........i'd hold off throwing money at the car with all these parts

 

[Mr OCD]

where do you live? if your local take me out for a spin and if it does what mine does it might put your mind at rest. i think that a momentary flat spot on part throttle is normal in many leons.
to summerise

at around 3k revs (remember my turbo clicks in after yours) on part throttle i occasionly get a flat spot, similar to a jolt but passengers do not feel it. the revs dont drop...or increase. nor does speed.

nobody has given me a reason for it. and ive asked on here and at jabbasport.

my theory is that the 20vt uses the turbo to accellerate. on part throttle the turbo starts to spin up and starts powering the engine when it suddendly its reached the amount of power required and pulls the turbo out. now youve a straight 1.8 engine haveing to push the turbo as opposed to being powered by it. the effect is a flat spot felt because its right at the point the turbo begins to benefit /or be a drag. by remapping your creating a bigger gap in the power/drag factor of the turbo. it dosnt happen when your part throttling at 4,5,6k revs as the turbos spinning fast enough not to add drag to the engine.

total guess.. but i think its close

I'm based just outside Manchester...

What you describe does seem to fit the description well... but mines around 2500rpm - this morning driving to work it wasnt too bad as I was driving round it really... but annoyingly in 6th @ 70-75mph is pretty much the revs that it happens at ... so slowing / speeding up marginally on partial throttle means I'm hitting the hesistation alot ... I also seem to get another just before 3000rpm then it accelertaes although does feel a little flat till about 4000rpm...

Now to me that simple feels as though its not holding boost... OR that the overboost is pulling the boost level up then cutting out hence the 'feeling' its not holding boost...

I want to get a boost guage on this car for diagnosis purposes - where do I take the vac feed from? - ideally somewhere can remove easily also after ...

Your theory sounds good but having had turbo'd cars before including a 300bhp modified RWD car I cant see why the Leon should be any different ... after all they use this engine in a multitude of VAG cars... do they all have the same problems?

I'm off to meet a SCN member tonight to pick up a few bits including a VAGCOM lead then we are going to go for a drive and see what can be logged... although with the freeware version I'm not sure if logging is possible - anyone know?

I have always put this hesitation (on both my Leons) down to the DBW throttle.....

I've had it before where I boot the car away from a junction, then have to back off the throttle and you get a scary moment where the car seems to still be accelerating with your foot off the power. Probably only a split second but scary. Maybe this isn't connected with the hesitation

OCD - have you tried the obvious Throttle body realignment (VAG-COM and key in ignition) assume you have.......best to start with the cheap options when using trial and error to diagnose a fault ........i'd hold off throwing money at the car with all these parts

I did a TB alignment just after I had the car remapped - I used my Cousins BOSCH ECU management to do it... I'm assuming VAGCOM wont make any further difference?

Indeed I'm not one for throwing money at cars as I'm pretty good at fault diagnosis... I've done all the work on my own cars for years but having never worked on the 1.8T engine before its new to me so learning as I go along ... I'm not a newbie to VAGCOM though - I used to use it on my old Corrado VR6 (2x2 connector) ...

I think next step is to try and run some logs on the car ...

I could replace the N75, N249 and DV but thats over 100 notes and I'd be annoyed if having replaced them had no effect

 

[traumapat]

I have always put this hesitation (on both my Leons) down to the DBW throttle.....

I've had it before where I boot the car away from a junction, then have to back off the throttle and you get a scary moment where the car seems to still be accelerating with your foot off the power. Probably only a split second but scary. Maybe this isn't connected with the hesitation

no thats the other quirk

i know what you mean like a slight over run... used to happen quite alarmingly after conversion but seems to have settled.

 

[LEE69]

Take the feed for the gauge of the FPR mate.

 

[traumapat]

I'm based just outside Manchester...

What you describe does seem to fit the description well... but mines around 2500rpm - this morning driving to work it wasnt too bad as I was driving round it really... but annoyingly in 6th @ 70-75mph is pretty much the revs that it happens at ... so slowing / speeding up marginally on partial throttle means I'm hitting the hesistation alot ... I also seem to get another just before 3000rpm then it accelertaes although does feel a little flat till about 4000rpm...

Now to me that simple feels as though its not holding boost... OR that the overboost is pulling the boost level up then cutting out hence the 'feeling' its not holding boost...

I want to get a boost guage on this car for diagnosis purposes - where do I take the vac feed from? - ideally somewhere can remove easily also after ...

Your theory sounds good but having had turbo'd cars before including a 300bhp modified RWD car I cant see why the Leon should be any different ... after all they use this engine in a multitude of VAG cars... do they all have the same problems?

I'm off to meet a SCN member tonight to pick up a few bits including a VAGCOM lead then we are going to go for a drive and see what can be logged... although with the freeware version I'm not sure if logging is possible - anyone know?

thing is though at part throttle ,having reached the target power level.. why would it hold boost? as far as the ecu`s concerned youve hit the power level and the throttles not asking for more.

a boost gauge is a must really. it should help you no end. most take the feed from the pipe coming off the top of the dv. if i was you id make it a permanant fixture.

http://www.seatcupra.net/index.php?option=com_content&task=view&id=500&Itemid=6

im not sure if other vags suffer this... a quick search through audi/vw forums might be worthwhile.

ive only had the leon turbo wise so nothing to compare. but the fact that 1.8ts runs enclosed instead of venting to atmosphere? could that make a difference?

as said i`d not go silly replacing stuff until your certain its a real problem.

yours happens at 2500rpm ...just as your turbo starts spooling. same as mine at 3k.

the only other thing you could look at is the dv itself... iirc yours is stock? ive found the apr r1 smoother than the forge/bailey piston dvs but the problem has lessened not vanished. bear in mind over 4 years mines been doing this... its regularly vagcommed and nothing changes. if something was faulty it should have died a while back, especially with the power im running.

mancs is a bit of a trip from brighton lol. but do find a local meet and attend.. im sure people will be happy to give there views on this.... forums are great but nothing more reassuring than someone with experience saying alls well.

 

[Mr OCD]

Take the feed for the gauge of the FPR mate.

Now to me that doesnt sound right... disturbing the FPR circuit to fit a vacuum guage isnt a good idea surely?