View Full Version : wandering boost
had a go in a leon cupra today and in 3rd, 4th 5th etc and above 4000rpm the boost did not stay the smae. you could feel it go down and up down and up as iff it was leaking from somewhere. any idea what would cause this. is it time to replace doggy bosch DV
Is brand new?
how many miles on clock?
dave
two years old, 12.5k miles
the leon can be a bit reluctant at higher rpms when new, but not in your case, plenty of miles on clock
dave
Sounds similar to mine...
ALmost like boost - then no boost - then boost, frequency of about 2 seconds???
RSD are having a look at it for me to check it is nothing to do with the upgrades. They suspect an air leak maybe?
Cheers - Rich
Have a look over at vwvortex.com in the 1.8T section. There is always a lot of talk about surging with these engines. It might give you some pointers as to the problem that you experienced.
Hi,
Looked at vwvortex and they seem to suggest that it is due to the stock N75 (wastegate???) being bad - somewhat similar to the stock DV not being brilliant.
So - it now seems that it might be due to either a waste-gate, the mass airflow sensor or the Oettinger Chip.
Does anyone have any ideas about any of these... or even better - has anyone else had this surging and gotten rid of it??
Cheers - Rich
It seems to be a problem on the older Leons, the ones pre-valve timing. Air flow meters have been replaced and to some good effect. However this is sometimes not the case.
Unfortunately, no-one has come up with a cure (yet) that i know of.
Its very strange tho. I wouldnt advise trying to move the N75 solenoid valve as i have been told they are glued at the factory, break one and its £xxx for a new un.
The Leon (older ones at least) have quite a pronounced boost spike just after the engine comes on boost (2-2500 rpm or thereabouts). When a car is chipped this spike is made even worse and on my car at least, it always felt like the boost was going too high and then the ECU was reigning in the excess boost (like a mini limp mode) causing this surging effect.
I had a bad MAF at the time as well which did make surging worse. A new MAF along with a revised program from AmD (removing the boost spike) and all the problems went away.
I have a new N75 valve (wastegate control solenoid) on order from ECS tuning in the states which is supposed to hold more boost for longer in the rev range. We'll see what happens once it's on the car.
How much will the ECSN75 be?
Have you tried adjusting the screw on the N75 to a different position?
It sounds as though the standard N75 might be as good as the standard DV????
R>
The ECS N75 is $89 plus about $25 to ship. I haven't touched my standard valve as it's not actually causing any problems at the moment.