Technical Stilo remains accelerated, help!

[bbnation]

I have been facing a problem for some time, engine speeds do not drop when they take the foot off the throttle, remain somewhere around 2000 for another 2-5 seconds
I cleaned the throttle and potentiometer and air sensor from intake gallery but no luck....what else can I do?

Stilo 2003 1.6 petrol, ecu is replace with 2 years ago.

 

[Ralf S.]

Did you ever change the lambda sensor? When they become old they can affect the idle speed ... but usually they make the idle lumpy (the engine revs go up and down, rather than staying steady).

Otherwise, I would have said it's the Throttle Position Sensor. Even if you cleaned yours, it may still be faulty.

If you can find a second-hand TPS sensor it's worth getting hold of it, just to see if it changes the symptoms. If it makes no difference at all, then you can understand it's not the TPS.

I'm guessing you already checked for air leaks on the intake side (after the throttle body).


Ralf S.

 

[bbnation]

yes lambda sensor is changed 1 year ago,
The problem is I still have another throttle and it does the same and I'm thinking of having the same problem both? ....no i quess
air leaks after the throttle body? must see.

Thanks for your time and reply :worship:

PS: no errors found...scan with ELM interface and MES

 

[Ralf S.]

Does the 1.6 throttle body have the Throttle Position Sensor on it?

The problem *sounds* like the sensor, so if you just changed the throttle body but kept the original sensor, then you would have the same problem.

On the other hand, if the sensor is attached to the throttle body and you swapped the throttle (with its own sensor attached) then that would prove the problem is not the sensor.

How is the throttle operated? Is it a cable? If you release the accelerator pedal, does the throttle close immediately or does the cable hold it slightly open (until the ECU adjusts the idle speed)? The throttle should be fully closed when the accelerator is off i.e. it should not move if you removed the cable.


Ralf S.

 

[Maigretnz]

Do you have MES? You can read what the throttle position directly. No guesswork.

 

[bbnation]

the problem is that it's not like this all the time, has only moments and that's not clear...
I change the throttle with her sensor which is attached to the throttle and are the same manifestations.
I did not have time to look for a leak , but announce here after.
1 question : Does the speed sensor have any connection with this? the sensor on the reed wheel? my water pump drain on sensor... until I noticed it flowing, now i replace water pump and no leak.
I'll scan it afterwards, I hope I can handle the throttle reading

 

[bbnation]

another problem P1121.
Verified with MES and when i press accelerate pedal engine run faster, but MES
looks like it's open at 2000 rpm only 1%, normal?

Do you have MES? You can read what the throttle position directly. No guesswork. - how?

 

[bbnation]

change with another throttle and simtoms is same.... sugestion? :worship:

 

[aschiuta]

Din ce oras esti ?

 

[bbnation]

Ai PM, ajutama cu ceva sfaturi daca poti te rog

 

[bbnation]

Today i change MAP sensor, but my problem is not solved.
Any help?

 

[Ralf S.]

The problem still sounds like the throttle position or the throttle position sensor.

I don't know the 1.6 engine.. but I guess it has a throttle cable rather than a fly-by-wire. If so, disconnect the cable when the engine is warm and let the engine idle by itself without the throttle cable attached.

Then rev the engine a little by pressing the throttle butterfly lever (where the cable attaches) with your finger... just to see what the revs do. It should rev normally and the revs should drop back to idle quickly. If it still takes some time for the revs to drop then the problem is not the cable (sometimes when there's a problem a naughty mechanic might adjust the cable so that it controls the idle speed).

I'm fairly sure there is a procedure to "reset" the throttle position sensor. It's worth trying to find that (search on here... then post the link so anyone else can find it here too) and try it out.

Check for any leaks at all. All the rubber pipes are old now so they can be loose. If you're in doubt, you can temporsrily put some PVC tape on the parts that have a pipe and clamp attached to them, so the tape makes the pipe a tighter fit.

If your clips are Klik clips they can become "stretched" over time, so try a hose clip instead (or a new Klik clip if you can get hold of one). A new one is always much tighter than an old one.

If you have no air leaks at all.. then have a look at the spark plugs. If one or two cylinders are sooty then you *might* have a leaky injector(s) and it could be the injector that is causing the revs.. by overfuelling when there's no throttle to let air in (so like putting a tint bit of choke on). But it's best to be sure before you start replacing injectors just to experiment. The more common cause is still the throttle postion sensor (clean it and then reset it) or air leaks.

The speed sensor doesn't do anything as far as the engine idle is concerned... and the MAP is now new (although I'm not sure it interferes too much when you close the throttle.. it's more interested when you're accelerating).

Does the engine otherwise idle okay?

When you drive along and accelerate slowly through the 1600-1800rpm rev band, is the car smooth or does it jerk or hesitate? Try that with the engine cold and also hot, to see if there's a difference. If it's a bit lumpy and it's worse when it's cold, then that may be a lambda problem. I'm not sure if a lambda problem will cause the revving issue.. but it might be a clue.


Ralf S.

 

[bbnation]

Thank you for your advice.Acceleration on Stilo is electric i'm sure.
Gas pedal have 6 wire and throttle is same, the problem with the cable is out
I clean potentiometer on throttle only with spray for contact cleaner, I did not erase anything inside the potentiometer...had?

I follow for clean my throttle this - https://www.fiatforum.com/stilo-guides/456315-how-clean-potentiometer-inside-throttle-body.html and relearn
I'll look at the hoses

 

[bbnation]

any help? sugestion? i have clean senzor and throttle....
I don't know what to do

 

[aijosh]

:-D Welcome to the club. I've been battling this issue for like forever now. I've been through 4 throttle bodies with mostly the same issue with all of them.

What you should do.

A::::
If you have more than one throttle body, open one of them totally, I mean dismantle the whole thing (the TPS is hidden inside black part so you have to figure out a way of prying it open without totally damaging it).

I normally just go at it (the silver area covering the sensor location) with a knife or screwdriver. After successfully opening that. Clean the heck out of it with Electric Contact Cleaner. DO NOT USE PENETRATING OIL the so called WD40. It eats up the rubber part and makes them expand without remedy. It also leaves oil residue everywhere.

When cleaning, try not to break any of those lines going round inside the sensor. I broke the outer line on the stock throttle body that came with my car and even though it has "started working" now, it doesn't rev past 3,000rpm. So I cant accelerate.

B::::
Check for air leaks at the intake. Really carefully check.

C:::: (maybe optional)
Its a bit of a hassle but I checked for signal between the ECU and 6pin connector entering the throttle body and mine was ok. So I want to believe yours is but you can attempt it

D::: (guessing)
It might be a ground issue. I'm looking into this. If it is I'll let you know.


END:::::::

PS:
Throttle body 2: Didn't work 95% of the time even with cleaning. Throttle remains limp at 2,000rpm
-------------
Throttle Body 3: Same P1220 error as the one is car
-------------
Throttle Body 4: Works ok, Revs ok BUUUUTTTTTTTT after a while of driving engine begins to judder and shuts of.
If I scan for errors I get code that says MAP sensor is bad (why is this throttle body saying the Mass air flow sensor is bad? :bang: but other ones don't? Other ones say TPS is bad)
Anyway, I bought one more MAP sensor making 3 MAP sensors and used with this throttle body but same error.

Engine judders every time I turn on but stops when I clear the error code. But only works for a little while again before it starts juddering.
---------------
.1 What I'm going to do next is to check if the timing is still correct
.2 Clean TPS on Throttle Body 4. I haven't opened this one yet.

 

[bbnation]

what is the best method to check air leak?

 

[bbnation]

hello, some help with this grafic? my throttle position insane

 

[bbnation]

any tips?

 

[Abarth L]

Hi

Wait first tell us what recorder you have used...?

According to your graph image that goes to a highly suspicious spamming website...??
I suggest using the forum to upload images.

All on graph reacts as it should as can be seen when pedal is pressed 100% at point 191.
Well pedal, throttle position?
Not sure since it can be the PV or SP that is on the grapgh marked as throttle position.

So it can be that the potentiometer on the pedal is broken, so do an ohms test.
Then it can be the throttle body getting stuck. So visually inspect and test with pipe off and car idling while reving slowly.
Can be connection to trottle body that is loose.

Air leak - won't cause this.

 

[bbnation]

Hi and thanks for your reply!
I use MES with ELM interface. I have full grafic here.Uploaded as ZIP, extension .csv not work.Please tell me your opinion

At point 191 gas pedal is released....0%

can you tell me which wire need to be tested? and what values ​​should they have?