Some strange boost problem

[evoms_gti]

so can someone verify that the symptoms Im experiencing are symptoms of fuel cuts? or at least inadequacy?

and how do you solve such a problem apart from down tuning the ECU program?

[evoms_gti]

reviving this thread again guys with updates on my issue!

so here it goes! the problem is not a fuel cut as we've run fuel pressure on data logs and everything is good and as smooth as it should be! which is really a big frustration for me because the hunt for the culprit starts again! 

also we 've downgraded the ecu settings by about 5% so were around 270hp +. like this the problem seems to be a bit milder than before but still there. on uphill roads the problem is as intense as before

please guys any further ideas? n75 maybe?

[Scottymon]

What state is your TB in?

[rich83]

Any errors logged in vcds?

[evoms_gti]

trully, i really dont know what state the TB is in! should I have it checked?

I have had some errors coming coming up! mostly bank 1 errors with message 'too lean' and flap motor failure!

as a first step I think i'll have the n75 replaced along with a new cam follower (even though this one has covered only 3k miles - but I do have HPFP internals)
and since its going in I shall have the revised intake camshaft 06F.109.101B installed since my car has the older less hardened version 06F.109.101A!

hopefully one of these solves my problems!

any more ideas are very welcome! thanks

Additional info: my car has 76k miles on it! dont know if that will help

[karl210]

Probably no help but has it just started happening after mapping? when i had my car custom remapped i had the same symptoms it would go like stink then at high revs the power would drop considerably and if i kept my foot down after about 4 seconds it would pick back up again. Took it back to the guy who re-mapped my car and he sorted it out. Cant remember exactly what he said it was but it was some confusing thing to do with the fueling going into safe mode and backing off or something along those lines. Have you measured injector duty cycle?

[bacillus]

I have had some errors coming coming up! mostly bank 1 errors with message 'too lean' and flap motor failure!

Could you post the full fault error messages?
Do you have the latest low fuel pressure sensor on your hpfp as the old ones were prone to fail.
Did you get your low pressure fuel pump (requested vs actual) and EGT logged?

What have you done about the flap motor failure error?

[evoms_gti]

Probably no help but has it just started happening after mapping? when i had my car custom remapped i had the same symptoms it would go like stink then at high revs the power would drop considerably and if i kept my foot down after about 4 seconds it would pick back up again. Took it back to the guy who re-mapped my car and he sorted it out. Cant remember exactly what he said it was but it was some confusing thing to do with the fueling going into safe mode and backing off or something along those lines. Have you measured injector duty cycle?

sorry i havent posted any updates! its only because i havent done anything to the car yet! Im out of funds unfortunately at the moment! hopefully next week will have n75 replaced for a new one. hope thats the problem

the issue pretty much sounds the same from what you are saying only difference is that mine starts picking up the pressure again once the issue reaches its max effect! it all happens in no more than 3 seconds max between drop and starting to pick up again

yes the issue appeared after remapping! however it could have been there before but it could have been not visible due to the low pressure the car operates on when its standard.

my tuner did log the fuel pressures on both lpfp and hpfp sides and they were ok!

[evoms_gti]

I have had some errors coming coming up! mostly bank 1 errors with message 'too lean' and flap motor failure!

Could you post the full fault error messages?
Do you have the latest low fuel pressure sensor on your hpfp as the old ones were prone to fail.
Did you get your low pressure fuel pump (requested vs actual) and EGT logged?

What have you done about the flap motor failure error?

i will take a picture of the faults next time i get the chance to connect it to vcds and shall post them here!

about the sensor as far as i know the car is the 2006 model so it must have the old one! im the second owner so im only speculating here!

to answer your last questionabout the requested vs actual pressure, i honestly dont know what kind o logs my tuner did, he just told me that fuel pressure were ok!

about flap motor havent done absolutely anything yet, but im planing to remove the motor completely and deactivate the operation of it through the tuning software.

IF its of any kind of help to give you some hints about whats the problem i can say that the problem is not occuring randomly it has a specific something (boost - revs - amount of fuel i cant say what) where it occurs!

when the boost was higher and the car produced HP 285ish it would occur earlier like 5200-5400rpm.
now that its HP 270ish it happens at around 6000rpm

the above was repeatedly happening especially on uphill

[evoms_gti]

came across this thread! http://www.mk5golfgti.co.uk/forum/index.php/topic,3242.0.html

everything described about the problem in the above sounds suspisiously similar to mine! eventually turned out to be the low pressure sensor giving false readings making the ecu exceed tolerance levels causing the drop in boost "safe mode". so I will have a go at replacing that sensor see if thats the problem!

low pressure fuel sensor G410 issue. i really hope this is it!