turbo 'stall' in low rev range

[noodles]

Hi, I know similar things have been discussed on here many times, but I am still having no joy with this. After having the throttle body cleaned a few months ago and a turbo pipe replaced, its back! (also had a coil pack replaced recently) When accelerating away from a standing start and changing up to second in a fairly relaxed manner (ie: 2nd picks up at about 1500 revs and rising, such as when navigating a roundabout) I get what I would describe as a turbo stall...

Basically the power is there to start with when the gear is engaged and the accelerator is pressed, but then half a second later, it feels like the turbo switches off.

Is this the classic symptom that everyone sees or is this different? I am not sure whether its a fault, or a characteristic of the engine, its always at this low rev range, and when accelerating slowly, or even just maintaining speed around a roundabout. When putting my foot down its not noticable really.

Should I not be trying to drive the car in 2nd at this low revs for a start? What else can I do?

[Goochie]

No, this doesnt sound like the classic problem that others (including myself) have suffered from at one point or another. In that instance, the turbo is running at reduced boost from the moment you put your foot down, it doesnt drop boost in the manner you've described.

If you were suffering with the same mystery problem as the rest of us I suspect, in ythe situation you've described, the car would feel like a non-turbo as soon as you set off in 1st gear.

[Mil]

When I had the 4x4 turbo for a few days I experienced the same thing..half way up the mid-range it would kind rev its guts off but not move, and then lock in and pull hard...din't know what it was, but i noticed it happened when i would gradually depress the accelerator instead of floor it.

[noodles]

Great! another mystery problem then!

This is definitely a step change, ie: power on, power off, power on again, all without moving my feet!!

Mil its pretty much what you describe there! Although I can only notice it in the low gears.

[Nigel26]

i occasionally get something similar with my vRS where it feels as though i've taken my foot off the gas and then reapplied it. almost like a quick kangaroo'ing motion.

mines booked in to the dealers next month to have the throttle body replaced but this is only as a result of having warning lights and codes logged on the ecu.

is the mpg poor? maybe the maf sensor needs a good clean.

[noodles]

i occasionally get something similar with my vRS where it feels as though i've taken my foot off the gas and then reapplied it. almost like a quick kangaroo'ing motion.

mines booked in to the dealers next month to have the throttle body replaced but this is only as a result of having warning lights and codes logged on the ecu.

is the mpg poor? maybe the maf sensor needs a good clean.

thats the one.

got 38mpg this morning on way to work on mixed motorway and A-roads, but the rolling average is 34mpg, so i would think thats fine...

The stealer did say the throttle body might need replacing when I last had warning lights on when they replaced a few other bits, but they cleaned it first, and told me to see how it went. Let me know how you get on and if you get it after the new throttle body.

I might drop by the stealer and have a chat to see what they say.

[Nigel26]

its worth talking to them about it again... i've waited for a month and a half just for the TB to come in... apparently theres been a bit of a shortage...

[rich1068]

Noodles,

Have you got an aftermarket DV eg Forge 007

Another stab in the dark!

[noodles]

no its completely standard. but i wondered if the dv might be a little flaky

well today I tried driving the car slightly differently today, ie: gave it a little bit more revs before changing up, and didnt get the problem at all... maybe I am just being too lazy with the flexible engine. I dunno... sometimes its so subtle I think I am beginning to go mad, but other times not subtle enough for me to ignore!

The trouble is if I can't reproduce it everytime, and there are no warning lights, and potentially no fault codes, coaxing the dealer into doing something about it could be tricky!

[Joel_vRS]

no its completely standard. but i wondered if the dv might be a little flaky

well today I tried driving the car slightly differently today' date=' ie: gave it a little bit more revs before changing up, and didnt get the problem at all... maybe I am just being too lazy with the flexible engine. I dunno... sometimes its so subtle I think I am beginning to go mad, but other times not subtle enough for me to ignore!

The trouble is if I can't reproduce it everytime, and there are no warning lights, and potentially no fault codes, coaxing the dealer into doing something about it could be tricky![/quote']

Im sure its the same problem i have.. sometimes i think im going mad...i think have i lifted ever so slightly off the accelerator? fully open throttle and apply more revs pushes it through the problem like you describe...i too do not have warning lights or fault codes and was given a clean bill of health at its recent service... but if i told some drive this down the road and back they say no problem there... its not there car they dont know what it was before and what its like now... its not a loss of power when you open the throttle there is still loads of power...its at half throttle and pootling when it lumpy and strange feeling... like it being stangled and you need to rev it to give it what it needs to move...

now i know it happens with totaly stock car i can maybe stop blaming the mods ive done FMIC, TIP, etc etc

AAAGGGGHHHHH im treaing my hair out!

Joel

[noodles]

tell me about! this car is turning me mad!

I am guessing the answer to this maybe to do with our driving and the way the turbo works. The turbo seems to spin at about 1500-2000 rpm, so when driving in this range, the pressure is always on the verge of spinning or not, hence when not fully on the throttle I am guessing the pressure could drop, leading to the loss in power for a second. A friend of mine used to have a pulsar gti, and apparently at around 2500 rpm when his turbo used to start winding up the same blip in power also occurred if he was not accelerating hard.

So from now on I am going to try to stop being a lazy driver and drive above the 2k rev range if possible! Its got to be better for the car in the long run anyway. But if it still does it then I will be seriously upset!!!

[Joel_vRS]

its hard to keep it out of the range mine does this in and not rev it ie using more fuel and being past the speed limit in a blink of an eye...ive not found a happy medium

Joel

[MaxLugo]

tell me about! this car is turning me mad!

I am guessing the answer to this maybe to do with our driving and the way the turbo works. The turbo seems to spin at about 1500-2000 rpm' date=' so when driving in this range, the pressure is always on the verge of spinning or not, hence when not fully on the throttle I am guessing the pressure could drop, leading to the loss in power for a second. A friend of mine used to have a pulsar gti, and apparently at around 2500 rpm when his turbo used to start winding up the same blip in power also occurred if he was not accelerating hard.

So from now on I am going to try to stop being a lazy driver and drive above the 2k rev range if possible! Its got to be better for the car in the long run anyway. But if it still does it then I will be seriously upset!!![/quote']

Remember that unlike the pulsar gtir, our turbos are electronically controlled (with the n75). I have the same "problem" with my 02 4x4 and i've come to the conclusion that it's just the way motronic translates part-throttle input in relation with the rpms. Also remember that spool-up occurs around 2000 rpm, and that the engine was designed to be run above 2000 rpm at almost all times. In fact, the best fuel economy occurs between 2500 - 3500rpm. Running below the boost threshold will kill the economy. So by driving a bit more spirited, you'll find the missing economy and you'll kill "the problem".

[noodles]

Remember that unlike the pulsar gtir, our turbos are electronically controlled (with the n75). I have the same "problem" with my 02 4x4 and i've come to the conclusion that it's just the way motronic translates part-throttle input in relation with the rpms. Also remember that spool-up occurs around 2000 rpm, and that the engine was designed to be run above 2000 rpm at almost all times. In fact, the best fuel economy occurs between 2500 - 3500rpm. Running below the boost threshold will kill the economy. So by driving a bit more spirited, you'll find the missing economy and you'll kill "the problem".

that is exactly the sort of information I am after! if its right, then nice one! top marks to you! virtual rep points going your way!

[bk1]

This same kind of "hesitation" issue has been discussed at length on an Audi forum I use, and no-one has found an all-out cure there, despite multiple people trying many different things to try and solve it (MAfs, N75, DV's, clutch, checking pipes, etc).

[noodles]

decided its definitely me driving like a pansy. more revs = no problem!

[888]

Remember that unlike the pulsar gtir, our turbos are electronically controlled (with the n75). I have the same "problem" with my 02 4x4 and i've come to the conclusion that it's just the way motronic translates part-throttle input in relation with the rpms. Also remember that spool-up occurs around 2000 rpm, and that the engine was designed to be run above 2000 rpm at almost all times. In fact, the best fuel economy occurs between 2500 - 3500rpm. Running below the boost threshold will kill the economy. So by driving a bit more spirited, you'll find the missing economy and you'll kill "the problem".

Is this 100% correct, i think this may be part of the problem im having, i tend to be lazy with the throttle, and tend to keep the car at 1500 - 2000rpm most of the time (town driving in 3rd or 4th), so the turbo is just spooling up, but i notice my mpg is shyte!!! so if i keep the revs a little higher it will make the car more happy?, and have better mpg???? would it effect reliabilty running in that rpm range all the time? sorry to sound think, its my first turbo car

[noodles]

Is this 100% correct' date=' i think this may be part of the problem im having, i tend to be lazy with the throttle, and tend to keep the car at 1500 - 2000rpm most of the time (town driving in 3rd or 4th), so the turbo is just spooling up, but i notice my mpg is shyte!!! so if i keep the revs a little higher it will make the car more happy?, and have better mpg???? would it effect reliabilty running in that rpm range all the time? sorry to sound think, its my first turbo car [/quote']

if you dont spool the turbo up very often it can seize so I am told. trouble with the octavia is the engine seems to be pretty torquey so you can drive it at the low rev ranges, many other turbo cars with bigger turbo's are impossible to drive off boost!

but I suspect that your low mpg is purely down to town driving, turbo cars are not renowned for good mpg for in town driving I am afraid!

[MaxLugo]

Is this 100% correct' date=' i think this may be part of the problem im having, i tend to be lazy with the throttle, and tend to keep the car at 1500 - 2000rpm most of the time (town driving in 3rd or 4th), so the turbo is just spooling up, but i notice my mpg is shyte!!! so if i keep the revs a little higher it will make the car more happy?, and have better mpg???? would it effect reliabilty running in that rpm range all the time? sorry to sound think, its my first turbo car [/quote']

If you ever drive a 1.8t with an automatic transmission, you'll see that the ecu tries to always keep the revs above 2000 rpm. Peak torque occurs between 2000 - 5000 rpm (if i remember correctly), and that's where internal combustion engines feel the happiest (top efficiency). Also, these engines were originally designed to be run within the turbo range, so reliability shouldnt be a problem. Just dont rev the cr4p out of it.

Do the economy test yourself. Get a long straight and get in 3th or 4th gear/2000rpm. Then accelerate until you can reach 3000rpm in the same gear. You'll see how mpg increase (or at least they should in a healthy 1.8t).

Also, just as noodles said, town driving/stop-and-go traffic is never good for economy, specially for turbo cars. :(