hi guys,

hope this is the right section,

ive just purchased a 2001 octavia vrs.

ive been driving round today to get used to the car and learn to drive it(my first turbo'd car)

when i boot it, the turbo cuts in and then stops and starts again.boost,off boost,boost in a way.

ive asked my good friend down my local garage and he says its either:temperature sensor(engine managment light is on and it comes down to this) or it might be the dump valve.

ive been told the standard dump valve isnt much good and the best upgrade is a forge 007???

whats peoples thoughts on this matter?

thanks in advance

this is a long shot but could just be the ASR kicking in, cutting power due to wheel spin. does it cud out in every gear or just when booting it in 1st and second?

i didnt think of it to be honest,

ive mainly noticed it in 2nd gear and maybe 3rd

i will have another go tomorrow and try turning it off and trying

thanks for your help

you need to scan the car for fault codes. Sounds like it could be a number of things. Faulty n249, n75 etc etc.

i had the car scanned and the fault came up with the temperature sensor which this also explains the temp gauge not working now and again.

would the temp gauge not working effect the boost?

whats ment by n249,n75?

sorry for the lack of knowledge,im new to this car

they are things that can control and cut boost. Get the temp sensor changed and take it from there.

thanks for your help mike,

ive been given a link to ebay for the sensor.

do i stay away from ebay for sensors?

http://cgi.ebay.co.uk/VW-DUEL-TEMP-TEMPERATURE-SENSOR-GREEN-4-PIN-GOLF-etc_W0QQitemZ180549837514QQcategoryZ9889QQcmdZViewItemQQ_trksidZp5197.m263QQ_trkparmsZalgo%3DSIC%26itu%3DUCI%252BIA%252BUA%252BFICS%252BUFI%252BDDSIC%26otn%3D15%26pmod%3D170529656191%26po%3DLVI%26ps%3D63%26clkid%3D7205406962025712290

I always get my sensors from the dealers mate, i have heard that people have had problems with the cheaper ones,

Is the car going and stopping through the power ? I'd thought if its a boost leak you'd have it on all the time not on and off .

Does it stop doing it after you restarted the engine ?

If it doesn't it could be the MAF going down . Correct me if im wrong though . Best way to try if it is , is to unplug the MAF and take it for a drive . (the traction light will be on if you unplug the MAF)

yeah thats what i will do,its not worth the risk

Is the car going and stopping through the power ? I'd thought if its a boost leak you'd have it on all the time not on and off .

Does it stop doing it after you restarted the engine ?

If it doesn't it could be the MAF going down . Correct me if im wrong though . Best way to try if it is , is to unplug the MAF and take it for a drive . (the traction light will be on if you unplug the MAF)

yeah the car is going and stopping through the power.

i havent really turned the engine off and tried it.

could also be a faulty dump valve.

could also be a faulty dump valve.

a friend of mine who is a mechanic has said for me to change the dump valve from the standard plastic one for a forge 007 dump valve as soon as he knoew i had the car.

went out again earlier today and the boost is full till 3000rpm and from there after its on and off on and off,

went to a garage today for tyres and was told it could the actuator????

compbrake do a cheaper version of the forge 007p, a few people on here have used them, they are about £40.

I am having the same problem as you mate. The boost kicks in then off then on throughout the rev range. I have the compbrake valve its good value for money but iam thinking my spring in my valve aint stiff enough now that i have the car remapped.

i will look into the compbrake valve.

just wonna get it sorted,

going to order a new temp sensor tomorrow.does anyone think that may effect the boost?

I am having the same problem as you mate. The boost kicks in then off then on throughout the rev range. I have the compbrake valve its good value for money but iam thinking my spring in my valve aint stiff enough now that i have the car remapped.

do u think the spring will be stiff enough for a unmapped octavia?

Is the map too aggressive?

If it only happens on loads of throttle and around 3200rpm then at say 4500rpm, it might be because of too much boost. Sometimes less is better.

Yeah phill the spring is fine for a unmapped car. I think it comes with two the one thats in the valve is the stiffer one from what i can remember.

Yeah higgy69 it kind of does do at that revs. It will be on full boost then ease off then on etc, its hard to explain.

Mine was same changed valve and improved massivly but then turned up i had a split breather too not noticed it since

Yeah i think iam going to upgrade my spring in my valve to a yellow one. I replaced my y breather pipe with a viper performance one a few months ago. I also had a good look at all my pipes on saturday whilst iam was instaling my airbox. Couldn't see or feel any split ones.

i think i have come up with the boost problem.

my front tyres are are extremly low of tread,(these are being changed thursday),

when the boost kicks in the wheels just wont to spin,and with the asp on it kills the power but then the power wonts to kick in again giving the feeling of the boost being on, off, on, off.

someone has said earlier in the thread this is what it might be,

i will get the tyres changed and see what happens,along with the temperature sensor

on the off chance,

what pipes do i need to check to see if there is any cracing od splitting?

Edited 21 February, 201115 yr by philiow

could my problem be down to the n75 valve?

Iam having the same problem mate but sometimes its worse than others, vag specialist up where i stay said it could be the n75 failing, best thing to do is try and source another one off another 1.8t engine and take it for a run to see if that makes a difference. Ill be doing this next saturday as my mate has a mk4 golf gti turbo

im hoping to get a vag com scan done very soon and see what come up with that