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greasemonkey2386
greasemonkey2386, ASE Certified Technician
Category: Car
Satisfied Customers: 274
Experience:  ASE Certifications A1,A4,A5,and A7 10+ years professional hands-on experience
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Mini Cooper S: Hi, I have this 2009 mini cooper s and i was

Customer Question

Hi, I have this 2009 mini cooper s and i was earlier having this problem that when accelerating the car suddenly cuts out, maybe like in fuel cut, feels like hitting the wall. And when this happened 2 times car went to reduced power mode and started revving up and down between 1000-1200 revs.
Did not get any fault codes then but now the problem has changed a bit and it happens almost everyday and no need for accelerating, I can just drive normally and this reduced power light flashes and goes away and then i get the P1638 code. And if i am enough unlucky car can hit this reduced power mode and again starts revving up and down and then comes also code P1639.

So are these 2 problems most likely the same and it just went worse with time?
I Also has checked what those codes mean: Throttle Valve Adaptation Control Throttle stuck temporarily/permanently. So first I thinked that maybe changing the whole throttle body would solve but when i searched the problem I think if i understood right that these codes doesn actually mean the throttle plate but the some valve that controls the plate.

Also i was thinking that can there be some other issue that makes the car believe that its the throttle fault? Asking this cause its not problem to change the TB but only if its quite certain that it would fix the problem.

Thanks!
Submitted: 1 year ago.
Category: Car
Expert:  Matt replied 1 year ago.
Hello

the 1st thing to try is just cleaning out the throttle body as they can cake up up with old oil vapour and dirt - this stops the throttle motor from operating correctly

if this is OK then This could be an airleak after the airflow meter, any air dragged in here isn't 'seen' by the ECU and so not compensated for and can lean the engine out and can also allow the engine to rev up when not desired causing rough running.
As its a mechanical fault it tends not to turn on the fault light and you can sometimes hear a 'hissing' noise with the engine running.

Check the hose clips for tightness and inspect the trunking for any cracks or splits and also all the vacuum system, the small bore pipes and fittings for cracks and missing parts.

The best way to locate a leak is to have the engine running and warm and then spray lighter gas /propane around each joint in turn. If the engine rev's up you've found your leak.
Work your way through each possible joint one at a time and you should find it. I use a slightly flattened piece of brake pipe and some rubber hose from the can of lighter gas to provide a spraying 'wand' and allow a direct blast of gas into each area, especially those difficult to reach with large implements.

It’s also worth getting the fuel pressure checked as if this is low due to a blocked filter or faulty regulator or even a poorly pump will all result in insufficient fuel being delivered to the engine


Might also be worth checking the wiring and connector to the airflow meter for any signs of corrosion or damage. you can do a quick fault find if you unplug the meter and run the engine without it.
if the engine condition is the same then chances are the meter or the connection to it is faulty

Air leaks are very temperature dependent as gaps can open or close up as things expand with heat, so the weather and engine temperature can effect them.

This leads them to be quite intermittent in the case of mild leaks

its also worth cleaning the airflow meter by removing it from the car and spraying the exposed sensor wires inside the tube with a brake or switch cleaner - ensure that the cleaner is one of the old fashioned, non Eco type that does not leave a residue

On no account touch the sensor wires with anything physical as they are extremely fragile
Customer: replied 1 year ago.

Thanks for the answer.


 


I did clean throttle sometime ago and it wasn very dirty then but i only viped with cloth like al the surfaces that can be seen.


 


But of course i did move the throttle plate with hands because of course i wanted to see how it moves so can that damage it?


 


And also i forgot to say that this car doesn have MAF sensor it just operates with two MAP sensors.


 


I have been hearing some maybe new little whistle sound that sounds a bit like Turbo diesel when give little throttle and release and revs goes done.


 


Also its now dropping oil a little that is new thing. But can that affect to the throttle fault?

Expert:  Matt replied 1 year ago.
Hello Jarno

providing the ignition wasn't on when you moved the throttle butterfly /plate then the throttle body should be fine

if its a MAP sensor set-up then it’s also worth getting the fuel pressure checked as if this is low due to a blocked filter or faulty regulator or even a poorly pump will all result in insufficient fuel being delivered to the engine
Customer: replied 1 year ago.

Hi


 


So it seems this gonna be trip to dealer then. damn it.


 


By saying to check vacuum leaks you mean lines from the air filter to intake manifold or is there also some other vacuum lines that should be checked?


 


Also i don really fully understand if fault codes point to throttle being stuck


How could vacuum leaks and fuel supply lead to that situation?


I mean car runs well besides this problem and it just occurs at tinmes and when it happens it usually goes away with one or few restarts.


 


Also Scangauge shows that Throttle position sensor is around 19% open at iddle when this P1638 code comes and engine goes to safe mode and starts revving up and down. And it stays in 19% even u drive or give gass in neutral. Normally TPS is 14% at iddle.


So does this show that it is really stuck?

Customer: replied 1 year ago.
Relist: Inaccurate answer.
Expert:  greasemonkey2386 replied 1 year ago.
Hello!
To answer your latest question, if the TPS is reading 19% at idle and it does not change I would suspect a faulty TPS sensor, if the throttle was actually "stuck" at a more open position than its idle position the engine would rev significantly higher at idle, it does not take much change in throttle body angle to increase engine rpm under load.
Customer: replied 1 year ago.

Hi and thanks for answer!


 


Was hard time to get home as its going worse and when it hits the safe mode on and starts revving up and down its almost impossible to get it away.


But noticed that if i just get moving right after engine start and keep revs enough up it wont start doing that:P


 


Anyway i got little more new "data" about this today.


 


1. it can get "stuck" betveen 15 and 19% TPS readings. And if it gets stuck under 18% it just keeps iddle revs little higher, around 1000 but when it gets stuck 18 or 19% it goes to safemode and starts this revving


 


2. When in safemode and revving up and down lambda loop is open, engine load quite high around 50% and giving throttle doesn change the tps reading.


 


3. also when releasing gas, lambda loop goes open, I don know if this is normal, just havent noticed that before.


 


4. One time today happened that it got stuck at 16% tps and then without me touching anything tps jumped to 19% and revving started


 


5. Also i said earlier that normally tps at iddle reads 14% but after i came home today from this second gear trip suddenly tps at idlle was most of the time 13% and it even went as low as 11%. So i was thinking that shouldnt that TPS reading at iddle to be like the lowest it can go and if so how it is now going lower?


 


6 And also it feels that just little tapping on gas sometimes give easily like 19% and 20% tps even revs don get over 1000.


 


Hope these helps something, its guite late and tired so surely i forgot something:P


 


Thanks!

Expert:  greasemonkey2386 replied 1 year ago.
ok where to start! haha
reading over all the new data I still am struck by faulty TPS that is the first thing that pops into my head.

#3: that is normal so no worries there

try this: key on engine off....watch the scan tool and push the pedal, note the tps % verse where your foot is...see if that is close to accurate

Customer: replied 1 year ago.

Hi and thanks again!


 


That was good advice to do and i did it.


So results i got was, heres a list again:P


 


1. Without pressing gas tps was 17% as at iddle it is 13-14%. Maybe normal as its not running but sometimes without touching anything it climbed to 18 and 19%


 


2. I felt little that when i tried to press the pedal very linearry tps reading did not rise linearry it went like it took a little break and then fast up few % and so on. But it wasn so noticeable as its hard to press with foot so sensitively and linearry:P


 


3. Tps reading at WOT was in highest 86% and that i know is normally from other Minis too but it didn always get so high in wot and sometimes it was 83% 84% and 85%


 


4. But the last one was interestin to see as i pressed pedal slowly down and tps reading arised until it stopped and even i pressed more it dropped to this 19%. Mostly this stucking happened around 50% and then when it dropped to 19 it didn change anymore even pressing pedal.


And once it got stuck in 21% and once at 32%. Switching power of and back on made it go back to 17% and moving again until it again stopped and dropped to 19%


 


So based on this i came in this conclusion in my little brains that surely there is something wrong in either tb or tps and i don think there is any doubt on that.


Basically again in my little brains i thought that either it could be that some fault in TB makes it to close itself or faulty TPS makes it think that its closed as i think that either thing would get these cut outs happen while driving.


Not sure how exactly TB works but if its like that the motor opens and spring closes then maybe it could be somethin like no signal and spring closes it or i could also think that if u try to press pedal and it mechanically stucks computer would stop giving signal to it to prevent any damages that might occur in the situation and again it closes then


 


Then i also started to think that could maybe bad signal from the pedal cause this? As earlier on summer it was on mechanic cause of carbon buildup and they said that pedal potentiometers had some little variations. At this time it was anyway left like it was cause i found that those problems was caused by this buildup and valve cleaning cured that. But now i am thinking that maybe those problems then was cause of buildup and this new thing and now its just getting worse.


 


Again I think that first I could check from my parents citroen C5 how its tps behave as it has same engine.


And after that i could take the TB of and just see how it moves when using pedal and check what kind of results that gives.


 


And yes also this that some minis have had problems that throttle gets ice and get stuck cause of that and those had just the same behaviour with the revving up and down


 


Oh my again so looonngg post:P

Expert:  greasemonkey2386 replied 1 year ago.
You definitely have something going on with the tps, with your scan tool can you go into the body module (i think) and watch the actual throttle pedal as you move it?
Expert:  greasemonkey2386 replied 1 year ago.
did you have a chance to check the throttle pedal yet?
Customer: replied 1 year ago.

No and with scangauge i cant see any info from the pedal. Just fault codes and information from some sensors.


 


But I quess i could hook voltage meter somewhere:P and see what that shows

Customer: replied 1 year ago.

I also wonder if this could be caused by a bad software as it did start after new ecu tune.


I just have been thinking it might be more hardware related as its getting worse and could think that software related would like more stable fault?

Customer: replied 1 year ago.

I just took intake manifold and TB out and seems that at least found something.

Throttle plate opens with hands easily maybe 1/4 of its movement and then it gets really hard to move. Really needs forse to open it more and i don think it was like that when i tried it last time in the summer. when it opens more then the rest of the movement is easier but when u release it the spring cant get it closed all the way.

 

Oh and i got new fault code P1637 that is Throttle Valve Adaptation Control, Control Deviation

Expert:  greasemonkey2386 replied 1 year ago.
Thats good! sounds like you have to replace the throttle body.
greasemonkey2386, ASE Certified Technician
Category: Car
Satisfied Customers: 274
Experience: ASE Certifications A1,A4,A5,and A7 10+ years professional hands-on experience
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Customer: replied 1 year ago.

Yes.


 


For now I got the old one working with greasing the plate pivots and turning it open and closed with hands.


 


Few days now without problem so that it was and seems working for now atleast. Feels good to drive without fear of car breaking suddenly:P


 


Thank you very much of your patience and effort of helping me with the problem!


 


Jarno V.

Expert:  greasemonkey2386 replied 1 year ago.
good, i am glad to hear it! let me know if you need any more help
Customer: replied 1 year ago.

Sure I will, Thank you!

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