Boost issue
- Thread starter 8bit
- Start date
No, you've got it the wrong way round. The actuator opens the wastegate when the turbo pressure has reached the pre-set level, about 0.8bar over standard air pressure on an unmapped LCR. This allows some of the exhaust gasses to bypass the turbine so it doesn't spin any faster than will generate the amount of boost the ECU has requested.
I appreciate that you want to help but please stop spamming the thread, you're just confusing the issue.
Haven't checked anything under the bonnet yet as it's always dark, wet and windy after work at the moment so won't get a chance until tomorrow, hopefully this crappy weather lets up a bit! I'm working all day today but may have some free time over the weekend? Cheers for the offer, I'll PM you shortly.
Well this made me chuckle Niall - I have been thinking long and hard about my issues again, and have realised that when I use my N75 switch (essentially unplugging it) the car is no longer noticeably slower, there is only a very minor change in how much power I have available.... This is making me wonder if I also have an N75, so I did a quick search for 'faulty N75' and see that my 'problem buddy' is thinking the same things haha!
As far as I can see, unplugging the N75 leaves it in its open state, I.E. feeding all the input to the wastegate (effectively bypassing any N75 functionality) and running minimal boost...
I don't know whether or not it is worth trying it with the N75 unplugged if you are thinking it is sticking? as this should leave it in the one state... having said that however, obviously you will run a lot less boost, so if it is something like a split hose creating a boost leak, the lower boost may not escape and you will think the problem is resolved as well....
This may not be of much help but just thought I'd mention the fact that you can try with the N75 disconnected just as another thing to try maybe?
Oh and you won't get an EML from it although it will log a fault code on the ECU showing N75 signal intermittent - scan the car with vagcom before trying this to see if there are any error codes shown with the valve supposedly operating normally, then try it unplugged and clear the code afterwards
Ben
Lol! If the N75 is fully open then it'll be keeping the wastegate open which will prevent the turbo from spinning up to full speed, so if your car is faster with it disconnected than without then maybe that would suggest a faulty N75 in your case. I'll have to try mine with and without N75 connected as well as with and without MAF connected over the weekend.
Still not convinced on a boost leak but if I can get it logged then one of those should show up with either a fault code of some sort (pressure drop between turbo and throttle) or with actual boost not meeting requested. I'd have thought a boost leak would always be there tho, not intermittent.
On the way to work this morning I tried flooring it in third from low revs a couple of times but today it seemed ok, the turbo could be heard spinning up from the mid 2000's as normal rather than nothing until over 3k then coming on hard. Hopefully get a chance to try some things tomorrow.
No sorry, I wasn't saying it is quicker with N75 disconnected, but the difference between connected/disconnected isnt as big as it used to be - when I first installed the switch it felt like switching between remapped/standard, whereas now there is very little in it.... on my last logs there was no evidence of a boost leak, so I wonder if its just not boosting as hard as it should be due to a faulty N75 sticking open and venting all the boost through the wastegate.... this would also be backed up by my turbo/DV not sounding as loud as they used to.....
Always something wrong with these damn things, I wonder if our cars were separated at birth lol
Always something wrong with these damn things, I wonder if our cars were separated at birth lol
Sticking throttle body. When cold the flap is getting stuck on the gunk, then boost pressure overpowers the gunk and you get your boost "hit". Colder the weather, harder the gunk. Once it warms it softens freeing the flap and the car feels fine.
Clean your TB you mucky pup
and re-align before doing anything else if i were you.They're definitely chips off the same block i reckon! I think mine wasn't really cared for properly by one or more of the previous owners, had a few of the common things to sort out since I got it. What's this switch you're talking about? A switch to turn the N75 on and off?
Sticking throttle body. When cold the flap is getting stuck on the gunk, then boost pressure overpowers the gunk and you get your boost "hit". Colder the weather, harder the gunk. Once it warms it softens freeing the flap and the car feels fine.
Clean your TB you mucky pup
Lol
Seems like a sound theory, will get that done as well, need to get a new TB gasket, hopefully next weekend. The car was doing it this evening on the way home from work again, like it was accelerating but forgetting it was meant to be on boost til about 3200rpm then bang, big-time boost all at once.Will try disconnecting MAF this weekend anyway and try and get the TB cleaned and realigned next weekend.
on the bright side if it does turn out to be the N75 they have gone over to a new part number and the price has dropped down to about £38 quid as i found out today
It sounds like it needs doing, its general maintinence and will rule it out before spending money.
The clue for me is the improvement with temp increase. Cant see why a faulty N75 would fix itself as the engine warms.... but then Ive never had an N75 play up so who knows? It is a Leon afterall
The clue for me is the improvement with temp increase. Cant see why a faulty N75 would fix itself as the engine warms.... but then Ive never had an N75 play up so who knows? It is a Leon afterall
They're definitely chips off the same block i reckon! I think mine wasn't really cared for properly by one or more of the previous owners, had a few of the common things to sort out since I got it. What's this switch you're talking about? A switch to turn the N75 on and off?
Lol
Will try disconnecting MAF this weekend anyway and try and get the TB cleaned and realigned next weekend.
Yeah I wired an inline switch up to the N75 which means I don't have to get out the car to disconnect it - runs minimal boost, and you dont have to be careful with your right foot to avoid wheelspin if its wet... I did it for economy and to avoid heavy foot syndrome straining the turbo + engine all the time! Worked well when my car was running alright lol
on the bright side if it does turn out to be the N75 they have gone over to a new part number and the price has dropped down to about £38 quid as i found out today
thats cool, do you have the new part number mate?
Managed to get a TB gasket and some Wynn's carb cleaner today but it got dark before I got home and had a chance to remove and clean the TB. On the way back the EML came on. Could this be caused by a dirty/stuck throttle body? Haven't got VAGCOM so will need to see if someone can scan for faults and do a TB reset soon.
Not sure whether it would throw EML Niall, but I would expect the EPC light would come on if the TB was stuck?
Apologies if this has already been asked but how old is the DV? If its over 10 months it could be sticking.
Not as much as ten months, was brand new when I got it back in April so I've had it on the car for 7. I have it fitted in reverse though, car isn't remapped so it's still on the standard spring, green presumably. Worth getting the Forge DV servicing kit and trying that?
Probably not that then.
I still think TB clean and reset. CTS can play up at certain temps as it dies but not heard this sort of symptom as described in your post.
Sounds more like somethings sticking till it gets warmed up fully.
Not heard of a dirty TB causing a light but if gets bad Id imagine the TB would be seen of out of calibration and that would throw a light.
I still think TB clean and reset. CTS can play up at certain temps as it dies but not heard this sort of symptom as described in your post.
Sounds more like somethings sticking till it gets warmed up fully.
Not heard of a dirty TB causing a light but if gets bad Id imagine the TB would be seen of out of calibration and that would throw a light.
I've had a code pop up a couple of times - 19534 - Throttle Control: Airflow at idle too low - although the last time that appeared it didn't bring up the EML. First time it was there it appeared with a couple of codes relating to the post-cat lambda. They were cleared and the EML never came back, that was in early April although the Airflow at idle too low code was there a couple of months ago. Having said that, according to this thread on the Ross-Tech site, that code can potentially bring up the EML.
The jerky boost symptoms seemed worse than usual today but then the temperature is a lot lower than it's been with this cold snap so I'm still thinking you're right about the TB needing cleaned. That's tomorrow's little project...
The jerky boost symptoms seemed worse than usual today but then the temperature is a lot lower than it's been with this cold snap so I'm still thinking you're right about the TB needing cleaned. That's tomorrow's little project...
Still haven't had a chance to clean the TB yet but noticed something else - sometimes (well, mostly) notice a significant smell of petrol in the car after its' been driving about for a bit - if the TB isn't opening enough then could this cause overfuelling and unburnt fuel? Would seem logical to me?
Pyro
Guest
i would have thought that would starve it of fuel
sorry im back
you're joking, right?
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