Hey all, New to this section of the forum, after living in the mark II fabia section most of the time!

 

I have just acquired a "new to me" Mark I Octavia vRS 2001, and have an issue with the power delivery...

 

specs: 153,000 miles, decat , 3" exhaust, stage one map (mapped after the decat )

 

I drove it home 200 miles, gently, and didn't use full throttle at all...

 

today, I have been out and about in it, given it a blast, and when you put your foot down boost and power come in strong, then back off, then come back, then back of, then come back.... all in an even wave, with the same timing... does this in all gears, including on part throttle.

 

otherwise runs fine.

 

I took it to my tame mechanic, and we had it up on the ramps, changed the fuel filter .....

 

 

there was also a lambda sensor loose on the exhaust which we tightened up....

 

we started with that , went for a drive, and all is the same.

 

no warning lights....

 

tame mechanic said lets start easy , with fuel (hence the fuel filter) , maybe the fuel pump next?

 

anyone else had any similar symptoms? or know what may be causing it? or know how to fix it?

 

planning on getting it back to my tame mechanic tomorrow.

 

Thankyou all!

Could be a number of things but a scan for any error codes would be helpful

Could be maf, a boost leak etc

Have a look at this: http://www.seatcupra.net/forums/showthread.php?t=262399

 

Badger5 gives some good info on which blocks to log which will indicate whether its getting enough fuel or not.

As said above could be a matter of working through a long list without codes and logging. While you're there stick n75 on the list too. If previous owner has modded it they may have tried to uprate it, same for the MAP sensor. I'd look at those readings and cycles if it's not a fueling issue. But yes, do some digging.

Have a look at this: http://www.seatcupra.net/forums/showthread.php?t=262399

 

Badger5 gives some good info on which blocks to log which will indicate whether its getting enough fuel or not.

 

 

As said above could be a matter of working through a long list without codes and logging. While you're there stick n75 on the list too. If previous owner has modded it they may have tried to uprate it, same for the MAP sensor. I'd look at those readings and cycles if it's not a fueling issue. But yes, do some digging.

Thanks guys, after the fuel pump my tame mech said we would go out and drive it with the computer attached to see whats going on

Good luck. Dan posted a good link there, some very good info

When I had the surge problem, it was simply a map issue. My pal uses Dimsport software for remapping cars, so we slapped one on my vRS and it wasn't too keen. On full-throttle pulls on the dyno, it surged two to three times through the rev range. Altering the values map just moved the surge points around. We put a standard Leon Cupra AUQ map on the car and it was silky smooth again with the right boost requested and met, and made the roughly expected 190bhp/189lbft.

 

I'm not saying yours is definitely a map issue, but if it feels like you are lifting off the throttle to reduce boost when you aren't, it could be something map-related. Find out who did the remap.

When I had the surge problem, it was simply a map issue. My pal uses Dimsport software for remapping cars, so we slapped one on my vRS and it wasn't too keen. On full-throttle pulls on the dyno, it surged two to three times through the rev range. Altering the values map just moved the surge points around. We put a standard Leon Cupra AUQ map on the car and it was silky smooth again with the right boost requested and met, and made the roughly expected 190bhp/189lbft.

 

I'm not saying yours is definitely a map issue, but if it feels like you are lifting off the throttle to reduce boost when you aren't, it could be something map-related. Find out who did the remap.

spoken to the company, they have been helpful (as much as they can without driving and logging the car) I have had my tame mech talk to the ECU today , its not a fueling issue, there is a loss of boost pressure between the turbo and the throttle body.... all pipes seem clean and good, His computer also checked everything else, all the hardware is working as it should..... soooooooo, first thing he suggested is the forge 007p, i have a standard dv on the way, and am going to swop them over see if it makes it better.... we have narrowed it down, so shouldnt be too hard to find now.... going to check ALL pipes hoses ect too, its getting on and the rubber will split..... I'm fairly certain we can fix it , just got to find the bit at fault! (make it sound easy don't I ?! lol) ..... I'll update on results. Its nothing terminal , thats the good thing

Hoses into and out of the pancake pipe worth checking, reckon you'll find it. A hole in the cooler isn't unheard of either. Can you get a smoke test?

Hoses into and out of the pancake pipe worth checking, reckon you'll find it. A hole in the cooler isn't unheard of either. Can you get a smoke test?

smoke test on the list .... step by step lol...

 

edit: do you have a pick of the "pancake pipe? or describe where it is? ta

Edited 3 February, 201610 yr by sharkrider

Sounds like a dodgy N75 valve to me.

smoke test on the list .... step by step lol...

 

edit: do you have a pick of the "pancake pipe? or describe where it is? ta

behind offside front wheel, should still be relatively shiny

Sounds like a dodgy N75 valve to me.

That was my first thought as well, previous owner may have tried to uprate it and got it wrong

Sounds like a dodgy N75 valve to me.

 

Is this a simple replacement part?

behind offside front wheel, should still be relatively shiny

to the the bottom of the intercooler? ta

Is this a simple replacement part?

to the the bottom of the intercooler? ta

Yes, get the right standard part number though, its up near the dv and the airbox

Yes, the pancake pipe is the squashed section, it allows for movement of the turning wheel, the connections there unsurprisingly get covered in **** and the jubilee clips get mullered

Edited 4 February, 201610 yr by YellowCar

looked it up, and spare N75 ordered today too ... just gonna change it all round to see if it helps

 

found this with a search, great diagram!

 

Sweet. By the way, I wouldn't bother with the 007, not needed, standard dv is fine and more reliable.

Sweet. By the way, I wouldn't bother with the 007, not needed, standard dv is fine and more reliable.

Absolutely, & only £25.

meh , I'm no good under the bonnet of cars, but all hoses seem fine (including pancake hose) all connections seem fine, N249 bypass done, sai mapped out. gonna change the dv , and N75 at the same time, if this doesn't fix it, I'm simply gonna hand it over to my tame mech, and say , "fix that" ..

I think the n75 might do it. Failing that get a smoke test, failing that log some fuel trims. That's probably the order I'd do it.

ok, update time... my standard dv and replacement N75 came today.... swopped them round....

 

 

car drives much better, most of the sudden cut in boost is gone, its still there , in and out, but at a greatly reduced rate, car is much more driveable, but feels a little flat, especially in the mid-range.... feels more like a standard 180bhp..... not sure if thats just due to the long gearing, especially in third...

 

going to buy a service kit for the forge item , and refit, see if it makes a difference.

 

If I cant get it running how I want, may bite the bullet, and buy a FMIC and replace ALL pipes to try and negate any boost leaks.

Progress then, did you say you'd tried a new maf? Also I seem to remember someone having similar sounding boost issues and they had a leak around the intercooler...might be worth a smoke test next

yup progress.... havent tried a new maf , can't hurt i suppose! I was focusing on the fact that the computer said loss of boost pressure after the turbo , and before the inlet.... there may still be a boost leak, he checked everything else, throttle flap, throttle pedal, fuel flow, ect ....maf wasn't showing any issues.. i will keep trying! lol...

 

just glad its more driveable now, just feels a bit flat.....

Sometimes the maf can be an issue without a code and can result in general lack of oomph. Could be worth trying but definitely a smoke test first, it sounds like there's a leak round your cooler, possibly even the cooler itself...