poor MPG STILL... after changing so many parts

[jedi-knight83]

Turbo cars eh  

You don't get these problems with N/A engines  

I'm troubleshooting a misfire at idle, stuttering / surging under load, clicking front suspension, clunking rear suspension and now my clutch is about finished 

tell me about it! this whole year has been one sensor or valve or flap after the other... im hoping for a year of problem free motoring next year :)

[vag12]

How do I do this logging with vcds? My car is running extremely low mpg and need to find out what the problem is, how do I log 32?

If you have a vcds cable then turn the ignition on (you don't have to start the car )>click select>engine>measuring blocks, type in 032 in the first group box then press go button and the values will pop up like in Jedi's pic.

Thanks again bacillus il give this a try and see what results I get, cheers 

[bacillus]

I'll have to have a go at this later in the week or next weekend. what kind of run should i log ? a quick A road blast?

Yes pre cat removed.

You want a third or fourth (preferable) gear run from around 2k to redline at wot. If you have dsg then you may have to stop at 6.3ish k rpm because of the box upshifting.
Can I assume that other parameters like boost, rail pressure and cylinder correction factors are all ok?

[jedi-knight83]

I'll have to have a go at this later in the week or next weekend. what kind of run should i log ? a quick A road blast?

Yes pre cat removed.

You want a third or fourth (preferable) gear run from around 2k to redline at wot. If you have dsg then you may have to stop at 6.3ish k rpm because of the box upshifting.
Can I assume that other parameters like boost, rail pressure and cylinder correction factors are all ok?

Ah ok just a normal power run then.

I can log boost, rail pressures etc when i do it. It feels nice and powerful so presuming all that is ok.

[h4rdy]

38MPG.. thats insane... ive never seen higher than 35... usually 25! 

Tbh its not all the time, but I can drive very economically.

35 is good.

Not seen over 30mpg for a while

[jedi-knight83]

Right I've got vag com for the evening so I can do a few logging runs. Can I have a list of the blocks that would be most useful to try to see what's causing my over fuelling.

Thank you :)


Sent from my iPhone using Tapatalk

[jedi-knight83]

Right I ran a couple of logs with a few difference things being monitored.

Click the link and it should auto download an XLS file

Run 1 and 2
http://u55158955@s300610021.websitehome.co.uk/UtilityImages/Run%201%20and%202.xls

Run 3 and 4
http://u55158955@s300610021.websitehome.co.uk/UtilityImages/Run%203%20and%204.xls

[bacillus]

Clicking your link does nothing on my laptop...   

[jedi-knight83]

Clicking your link does nothing on my laptop...   

you checked your download folder?

I can email if you pm and address

[rtechniki]

It went south after messing around with induction kits, I would say maf but dont go and buy one, borrow one or run with it unplugged so we what happend with the MPG.   And it you failed the MOT with just the precat removed then there could be other underlaying issues, fault lambda sensor, exhaust not fully air tight, PCV issues ect...



Best bet it to get booked in for an advance logging session and health check on the dyno.   

Last time I saw the car the MAF seal was not fully sealed so the ADD/MULT and STFTs would have been reading incorrect so there would have been no way of getting a good picture of whats going on.

Its hard to try and diagnose a fault from remote logs,  Its easy for me to log on the dyno using the eddy brake to control the load so I can look at the data in real time and compare with external sensors.

Nick

[jedi-knight83]

It went south after messing around with induction kits, I would say maf but dont go and buy one, borrow one or run with it unplugged so we what happend with the MPG.   And it you failed the MOT with just the precat removed then there could be other underlaying issues, fault lambda sensor, exhaust not fully air tight, PCV issues ect...



Best bet it to get booked in for an advance logging session and health check on the dyno.   

Last time I saw the car the MAF seal was not fully sealed so the ADD/MULT and STFTs would have been reading incorrect so there would have been no way of getting a good picture of whats going on.

Its hard to try and diagnose a fault from remote logs,  Its easy for me to log on the dyno using the eddy brake to control the load so I can look at the data in real time and compare with external sensors.

Nick

Ah.. the man himself. New log in?

What should happen with the maf unplugged?

MAF seal is now replaced and sealed tight.


I'll get it booked in with you asap i think.... just need a spare day when i can bring it over :)

[rtechniki]

It went south after messing around with induction kits, I would say maf but dont go and buy one, borrow one or run with it unplugged so we what happend with the MPG.   And it you failed the MOT with just the precat removed then there could be other underlaying issues, fault lambda sensor, exhaust not fully air tight, PCV issues ect...



Best bet it to get booked in for an advance logging session and health check on the dyno.   

Last time I saw the car the MAF seal was not fully sealed so the ADD/MULT and STFTs would have been reading incorrect so there would have been no way of getting a good picture of whats going on.

Its hard to try and diagnose a fault from remote logs,  Its easy for me to log on the dyno using the eddy brake to control the load so I can look at the data in real time and compare with external sensors.

Nick

Ah.. the man himself. New log in?

What should happen with the maf unplugged?

MAF seal is now replaced and sealed tight.


I'll get it booked in with you asap i think.... just need a spare day when i can bring it over :)

The primary fuel is based on MAF kg/hr and a singel value fuel injector constant which basically allows the ecu to know how many ms the injectors need to open to match the required lambda.  If the maf is reading wrong then the first 02 sensor will compensate can corrent the injection times to keep the lambda where it is needed to be, this is called fuel trims.   There could be areas on the maf that are reading wrong causing the fuel trims to read high.
If the maf is fault it will also mess up the ecu torque / load structures which means less time can be given which mean reduced engine combustioneffichency.  By unplugging the maf the ecu will revert to a generic mode for maf reading and use other sensor to work out load.   If you unplug the maf and the car seems to perform better or your mpg goes up by 3-4mpg then its a good sign the maf if fooked.
You are 100% safe driving with the unplugged.

Nick

[driver rider]

Hope you get this sorted Jedi.

[rtechniki]

Hope you get this sorted Jedi.

He will when he trades it in for a TDI..lol

[jedi-knight83]

Hope you get this sorted Jedi.

He will when he trades it in for a TDI..lol

LOL.

I will when i have enough time to look into it more and log it for Nick... just so flipping busy at the moment. I should have a few days next week.