Hi all i am new to this, Im on my second octavia rs 2003 1.8t. it does seem to be remapped also cat back exhaust and k&n panel filter

 

I have a problem the car drives fine in first and second but sometimes it seems to drop boost around 4-5rpm. So for instance in 3rd it will pull strong to around 5rpm then all of a sudden feels like i have put my brakes on and the car looses all its power..

 

got no cel light no obvious problems

 

Thanks

Edited 29 July, 20169 yr by gsaiev1987

Try a scan, code may have been thrown without CEL, my money is on an air leak or weak actuator but to be honest at this stage it could be anything.

Crank sensor possibly on the way out, takes a while to throw a code, mine did the same at 5k, also became difficult to start. 

mine has started to this but much lower in the rev range about 3500 on half throttle. you can actually here it dump the boost on the DV continue like normal afterwards. 

 

my intital process will be 

boost leak check because theres a million pipes and connections that fail regardless of how much silicone hoses and checks i do 

N75 value i want to see what it does when i data log this when it does make the flat spot/loosing boost.

the dump value it self i want to make sure it can still hold boast correctly 

both those units for me are under 2 years old and OEM units for me so i don't think they will be the problem

 

The next 2 are more tricky to diagnose as there more age related i think could be the issue is the fuel pump because i know its original and I'm asking it to work harder (my car is stage 2) 

The last is the actuator and turbo it self again i know both are original so they are suspect

 

I'm sitting on 110k miles now and been remapped from 60k 

I can vouch for the crank sensor.. the same thing's just happened to mine.

after replacing everything was fine.

Hi all thanks for all the comments. I have posted a video here please have a look. im in 2nd gear to start which revs all the way to redline with a few judders or so, But as u can see when i go into 3rd it stops and feels like im hitting a rev limiter at 5k.. this does not happen all the time. You can hear the car

http://<embed width="440" height="420" type="application/x-shockwave-flash" src="http://v9.tinypic.com/player.swf?file=359epo5&s=9"><br><font size="1"><a href="http://tinypic.com/player.php?v=359epo5&s=9'>http://tinypic.com/player.php?v=359epo5&s=9">Original Video</a> - More videos at <a href="http://tinypic.com">TinyPic</a></font>

 

http://View My Video

http://<embed width="440" height="420" type="application/x-shockwave-flash" src="http://v9.tinypic.com/player.swf?file=359epo5&s=9"><br><font size="1"><a href="http://tinypic.com/player.php?v=359epo5&s=9'>http://tinypic.com/player.php?v=359epo5&s=9">Original Video</a> - More videos at <a href="http://tinypic.com">TinyPic</a></font>

 

http://View My Video

Crank sensor throws a 16706 code Iirc and EPC light comes on and will be difficult to start. Also check your brakelight switch, its dual circuit and will cut the ECU randomly if faulty though brakelights may still operate. Had a stage 2 4x4 and this cost me a lot of time and money to track down to the brakelight switch. Both parts about a tenner non OEM. As suggested get codes read.

Edited 13 August, 20169 yr by modra_vrs

Ive had all the brake switched checked, All ok

Bad fuel pump