boost problems - hesitation and surging?

[jayjaycupra1.8t]

HI all

I have an intermittent hesitation on boost issue. Doesnt do it all the time but sometimes when I slam my foot down itll boost then hesitate then whack all the boost out??

I also have a surging problem ( I think ). ...when in 6th gear on motorways with my foot all the way down boost will rise to 20psi hold for a bit then drop to 12 then rise back to 20 and so on...can feel it in the car as well as see on my boost gauge?

This has only started to happen in the last week or so.

I have done the pcv delete vented to atmosphere. Recently installed a forge tip.

searches point towards pcv system (which I dont have), n75, MAF, and actuator. But I have also read countless threads where is hasnt been resloved by changing the above parts....or threads where the op has never come back and given their solution

any help would be much appreciated

 

[N1njaboy]

Possibly a stupid question !! Have you checked the diverter valve (or cleaned it out if it's been uprated)

 

[jayjaycupra1.8t]

Hi mate thanks for the reply

yeah I serviced the dv when I fitted the forge tip. It was fine for a few days then just started doing this.

the dv is a cheap copy of the 007. Will give this another clean at the weekend and see if it helps at all. Might have used the wrong/too much grease on it.

any ideas if the dv woukd cause the surging??

 

[N1njaboy]

I really wish I could say yes lol but I can't. Try taking the dv off, push the piston up and hold it there, then block the vacuum port on the dv with your finger/thumb, let go of the piston and if it returns then I'd say it's possibly not helping as it isn't sealing properly. (Hope you can make sense of that)

 

[jayjaycupra1.8t]

Yeah perfect sense mate.

did test that when I serviced it and it worked fine. Will have a look around at the weekend.

thank you

 

[Alexis27]

N75 valve if it's never been changed. Solved my kangaroo boosting

 

[jayjaycupra1.8t]

Not sure if its ever been changed to be honest. Its an F version.

on the lookout for a F version as we speak on ebay....but also looking for an ecs or H too to try out.

I have a manual boost controller sitting in the house....might bypass the n75 as a test and see if this helps. ...what do you reckon??

 

[Alexis27]

F was what came with the car I think. They seem to wear out after 8 or 9 years, regardless of mileage.

 

[ScottyBoi]

Turbo low boost problem

Hi all,

I have a seat leon 1.8 turbo

When my car is cold it will boost as normal but when it gets to temp it won't boost as well as it should do, why would this be?

I've just recently put the recirculating dump valve back in its normal place as I had a HKS dump valve on the intercooler pipe, from the previous owner.

But I do have oil in the 1st 2nd n 3rd cylinder due to a rocker gasket leak and going to get this done ASAP could this be the problem?

Thanks guys

 

[ibizacupra]

whats plumbed wrong or not on correctly?

 

[jayjaycupra1.8t]

Gald you chimed in bill ive heard your the best....

so since posting I have checked the dump valve again....there was a rubber o ring at the bottom of the piston (fake 007) which has now gone. I can only asume that the turbo has eaten it. I have bought a standard valve from my friend from an s3 and when I put it on it was better....and when I out it on in reverse was even better still.

the surging and besitation has gone. However it still does not seem as quick. It is only peaking at 18 whereas is used to peak at 20-21. And it is now dropping off very quickly.

what do you think??....dump valve still at fualt or damaged turbo??

Many thanks