Hesistation on part throttle...

[LEE69]

Why? your only teeing in to get a vacuum feed, the vacuum is still there?

I read on here the dump valve is not the best place to tee from as well.

 

[traumapat]

Why? your only teeing in to get a vacuum feed, the vacuum is still there?

I read on here the dump valve is not the best place to tee from as well.

fpr or dv should work fine. only time coming off the dv pipe will fail is if using a split r dv which has to go fpr.

i think your right mate that the fpr will give a more accurate reading.. but the majority on here use the dv line.

 

[Mr OCD]

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.

If you think about it you prod the throttle to accelerate on partial throttle and the ECU requests 'some' boost to give required acceleration - this is controlled by the boost controller... its obviously not just an 'all or nothing' boost request therefore once it has hit the required boost level for the throttle transition it should actually hold that level until acceleration has been met then drop to negative vaccum... at least thats how my other turbo car worked as you could see this on the guage.

I think the issue lies in once the throttle level has been hit the ECU is dropping the boost out of the circuit too hard ... like a hard dump thats more noticable when running higher boost. This tells me that either the DV or the actuator are struggling with the boost levels... if it was an issue with the controller then it would struggle to maintain boost at higher levels?

At least thats how I've thought it out over the last couple of days ... my issue is even on hard throttle it feels as though its got a flat spot around 3k rpm so either the boost is dropping out or its something to do with the overboost circuit... but I defo have the hesistation you describe around 2500rpm but I think this is more to do with the boost dumping too hard...

Anyone know how the overboost / how much overboost the 1.8T gives?

Why? your only teeing in to get a vacuum feed, the vacuum is still there?

I read on here the dump valve is not the best place to tee from as well.

Vacuum is still there but that vaccum is used for fuelling ... interfering with it could cause fuelling issues...

I took the feed from the DV on my old car with no issues so will probably do this instead...

 

[Mr OCD]

Cool discussion chaps btw

Helps me get my head round how the boost system works on the LC ...

 

[traumapat]

but thats just it at 2500rpm... everythings just starting to happen turbowise. its stopped being a drag and starting to have a positive effect. suddendly the ecu cuts the turbo... theres nothing worthwhile to dump as nothings built up and as the turbo suddenly has to be pushed by the engine its felt as a flatness/holding back of power.

as the cars recirculate the boost could that be the smoothing mechanisim? perhaps theres not enough boost to make this happen?


its a great disscussion but realise theres lots of guesswork... at least from me

 

[Mr OCD]

but thats just it at 2500rpm... everythings just starting to happen turbowise. its stopped being a drag and starting to have a positive effect. suddendly the ecu cuts the turbo... theres nothing worthwhile to dump as nothings built up and as the turbo suddenly has to be pushed by the engine its felt as a flatness/holding back of power.

as the cars recirculate the boost could that be the smoothing mechanisim? perhaps theres not enough boost to make this happen?


its a great disscussion but realise theres lots of guesswork... at least from me

Agreed... I've also noticed its much worse when the car is cold

 

[Ruddmeister]

ECU requests 'some' boost to give required acceleration - this is controlled by the boost controller... its obviously not just an 'all or nothing' boost request therefore once it has hit the required boost level for the throttle transition it should actually hold that level until acceleration has been met then drop to negative vaccum... at least thats how my other turbo car worked as you could see this on the guage.
..

The ECU works on Torque requests.....

Basically the ecu takes throttle pedal position as a driver torque demand, looks at current engine torque, calculates the new torque, splits off the torque delta into igntion / airside / fuelling torque demands, then tries to get to this condition.

Me7.1.1 has approx 14,700 calibrateable parameters, including something like 600 2 and 3 D "maps"

It takes a lambda demand value (a product of a large number of maps including steady state fuelling, component protection lambda, the 2 main ones) Then measures the current plenum conditions from it's temp / MAF / MAP sensors, then corrects for manifold filling effects, again MAP / TPS / EGT / BARO / TEMPS etc, comes up with a base fuel mass. Then if within the "closed loop region" as defined by a further sub strategy, it adds the upstream lambda PID controller correction, and the rear sensor bias fueling offset, then adds the current filtered value of the fuel adaption RAM. This final fuel mass is then corrected for transient effects based on MAP and TPS, then a final fuel mass is turned into a fuel injection pulse width with further correction from fuel temp / pressure. Finally it looks up the injection angle, calculates the start and end of injection crank angle, then at the right moment actually injects the fuel. The resultant fuelling and air flow conditions are then reworked back into a flywheel torque figure and this is compared to the driver demand.

And i havent even mentioned OBD, Purge, Ignition, EGAS, CCM, traction control, transmision torque control, boost control and about 30 other important things, believe me, modern EMS systems are seriously trick bit of kit.

Always makes me laugh when i hear F1 comentators going on about how F1 technology improves road cars when it's really the other way around!


.......With the DBW throttle being a key part of the system I still think it plays a part in this hesitation perhaps coupled with the fact that at 2,500rpm as Pat says the turbo is just spooling.

[above bit in italics cribbed from someone intelligent]

 

[Ruddmeister]

Agreed... I've also noticed its much worse when the car is cold

Mmmmm I was told that this could be related to emissions when cold....

 

[Mr OCD]

Mmmmm I was told that this could be related to emissions when cold....

Great info dude... I'm going to need to read that a couple times to digest...

Emissions are spot on ... I have the printout from emissions test taken last Saturday

 

[Ruddmeister]

Great info dude... I'm going to need to read that a couple times to digest...

Emissions are spot on ... I have the printout from emissions test taken last Saturday

Cribbed from here to read in context
http://www.seatcupra.net/forums/showthread.php?t=43216&highlight=14,700&page=2

It's safe to say Maxtorque knows what he's talking about


Some good reading on related topics on VW vortex if you have the time to do some digging........
http://forums.vwvortex.com/zerothread?id=2363607

 

[Mr OCD]

Cribbed from here to read in context
http://www.seatcupra.net/forums/showthread.php?t=43216&highlight=14,700&page=2

It's safe to say Maxtorque knows what he's talking about


Some good reading on related topics on VW vortex if you have the time to do some digging........
http://forums.vwvortex.com/zerothread?id=2363607

Excellent ... plenty of reading for me at lunchtime

I've got a VAGCOM lead now so once I figure out how to get it working will be able to start logging

Funnily enough have noticed the hesistation is barely noticable in 4th,5th and 6th gears... odd!

 

[Mr OCD]

Ok ... VAGCOM plugged in and working (I need full version!) ... brand new MAF and I have got:

16486 - MASS AIR FLOW SENSOR (G70): Signal too low

 

[Mr OCD]

16486/P0102/000258 - Mass Air Flow (MAF) (G70): Signal too Low
Possible Symptoms
Probably no serious malfunctions
Loss of power
Possible Causes
Wiring and/or connections (short circuit?)
Mass Air Flow (MAF) (G70) defective
Possible Solutions
Check wiring and connections
Check / Replace Mass Air Flow (MAF) (G70)
Special Notes
In MY 1995-2002 (?) in Europe at VW-diesel-cars G70 had the bad reputation of slowly losing his performance, causing loss of power. It's not a matter of defective or breaking down, but it is filthy / dirty (not easy to clean). You can check functionality by making a log in [01-engine], [meas.blocks-08], group 003 (3e gear, full throttle, from 1700-4000rpm

 

[traumapat]

id disconnect the battery for 10mins ... then run again.

 

[Mr OCD]

id disconnect the battery for 10mins ... then run again.

What makes you say that fella?

 

[Mr OCD]

Its going on the rolling road tommorrow afternoon so is this wise?

 

[traumapat]

What makes you say that fella?

clears the ecu memory of any faults. not sure exactly but wondering if the ecu still thinks the old maf is on. battery disconnect will clear any faults so if they come back you know its current.

its not unheard of for a new maf to be faulty... but hopefully not the case here.

 

[traumapat]

Its going on the rolling road tommorrow afternoon so is this wise?

you could make a note of the exact code... in case it dosnt come back but fault remains? it may fix it?

 

[xd-data-ii]

clears the ecu memory of any faults. not sure exactly but wondering if the ecu still thinks the old maf is on. battery disconnect will clear any faults so if they come back you know its current.

its not unheard of for a new maf to be faulty... but hopefully not the case here.

You're right! That error code would have been there from him disconnecting the maf and taking it for a drive
Think it needs to be reset.
Should disconnect the battery

 

[Mr OCD]

clears the ecu memory of any faults. not sure exactly but wondering if the ecu still thinks the old maf is on. battery disconnect will clear any faults so if they come back you know its current.

its not unheard of for a new maf to be faulty... but hopefully not the case here.

Battery was disconnected when I installed the new MAF...

you could make a note of the exact code... in case it dosnt come back but fault remains? it may fix it?

Code has been logged via VAGCOM

You're right! That error code would have been there from him disconnecting the maf and taking it for a drive
Think it needs to be reset.
Should disconnect the battery

As mentioned battery was disconnected, MAF installed, Plugs installed and then battery reconnected up ...

So its defo a fault code from the new MAF...