View Full Version : Self revving and juddering on overrun
Recently whilst stationary at traffic lights etc, the car has been revving up to about 1200rpm with no movement of the throttle, it only does it for a couple of seconds. Also whilst slowing down in gear on overrun the car is noticeably juddering.
My thoughts are either the water temp sensor or the lambda. Lambda is a year old and a Bosch one. I will get around to testing the water temp sensor soon but wanted your thoughts first.
Thanks
Jack
cuore_sportivo_155
15-06-08, 19:09
the car doesn't have an idle actuator?
on overrun, the fuel should be cut if the ecu recognises the event as such, which i suspect is not the case... look into the TPS sensor...
the car doesn't have an idle actuator?
Good point, forgot about this obvious bit. I will clean it out.
on overrun, the fuel should be cut if the ecu recognises the event as such, which i suspect is not the case... look into the TPS sensor...
Will do,
Cheers!
Juan AR155Q4
16-06-08, 04:27
Just clean the idle valve, and problem solved.
Didn't someone post a "how to", I removed my idle actuator a while ago but couldn't see what I was cleaning :lol:
wrinx
Yes:
http://forum.berlinasportivo.org/showthread.php?t=1006&highlight=idle+control+valve
And I tried to take mine apart tonight but couldn't work out how. The solenoid bit is the same but the rest (the casing part) is plastic, not metal like in the photos. So I put carb cleaner in and gave it a good shake. Not sure how improved it is. I will monitor it for a while.
THIS IS THE THREAD (http://forum.berlinasportivo.org/showthread.php?t=563&highlight=cleaning) but as you say Jack, nothing like the part I was trying to clean, which sounds remarkably like the one you mention...I must have pulled the wrong bit off :lol:
So where is the metal bit in the other thread??
wrinx
Found it....
This device is located between the engine and the steel tubing that goes from the IC to the throttle body.
You need to take out that tube (just to work better), then take out two nuts (10mm) and realese in and out hoses.
Then you'll have to unscrew 3 bolts and voila!!! It's out!!!
Remember to measure were the little piston is located before you unscrew the little nut (4mm I think).
wrinx
That is definitely the part I removed, it is definitely different too :(
Juan AR155Q4
17-06-08, 02:52
The one in the post is from a Lancia Delta. As both of you are saying, in Q4 is mounted in a platic case.
The procedure is the same.
But what do you have to do to take the solenoid out of the plastic casing? Do you just pull it out or twist it? I do not want to break it:
http://www.kkk.netsons.org/Delta%20utility/Pulizia%20vae/vae4.JPG
http://www.kkk.netsons.org/Delta%20utility/Pulizia%20vae/vae19.JPG
Just pull it out....it won t brake i'm 200% becouse i did this a few times:)
Just done mine, no problems at all. The plunger was a bit sooty.
Forgot to measure the 4mm distance but I'm not convinced it is that critical...we'll see :lol:
http://i54.photobucket.com/albums/g118/wrinx/Q4/Idle%20Valve/0-0003Medium.jpg
http://i54.photobucket.com/albums/g118/wrinx/Q4/Idle%20Valve/0-0005Medium.jpg
http://i54.photobucket.com/albums/g118/wrinx/Q4/Idle%20Valve/0-0006Medium.jpg
wrinx
It went away for the 300 mile round at the weekend but tonight it was misbehaving by all of a sudden cutting out whilst waiting at some traffic lights. It restarted ok then cut out again whilst idling but took a longer than usual turn of the key to start it again.
In between whilst these two cut outs happened it was a bit hesitant to give usual power, it was kind of like it had massive flat spots then at one point when lifting off the power it felt as if it held the throttle open for a few seconds at 2K RPM.
Once home and idling on the driveway the revs went up for a second or so to about 1500 RPM on their own like they did before but in the few mins I ran it, no cut out.
All I have done last week is take the idle control valve off and give it a shake with carb cleaner in. I have not done the strip down of it yet but I might just do that soon.
When I had a look and a listen under the bonnet I felt as if I could hear a faint hissing as if there was an induction leak, but even if there is would it affect it if its before the butterfly as there is no air flow meter on this engine.
Any ideas? I am yet to check the throttle position sensor.
Cheers all,
Jack
arjunior45
02-07-08, 00:45
All I have done last week is take the idle control valve off and give it a shake with carb cleaner in. I have not done the strip down of it yet but I might just do that soon.
strip it down and clean it as it is meantion by wrinx and Juan.
Giving it a shake with carb cleaner do nothing at all. That's what 'my' mecchanic did to mine a mounth ago and when I striped it down apart the spring that was missing it could not have been more derty than it was. So,do not be lasy.
Remember to count the turns of the bolt when you'll remove the springs!!!
Nick
Remember to count the turns of the bolt when you'll remove the springs!!!
:cry::tapedshut:...I forgot! Wonder how important it is?
wrinx
why count? messure it it shopud be around 4mm.
arjunior45
02-07-08, 11:55
:cry::tapedshut:...I forgot! Wonder how important it is?
wrinx
I can't say for sure but I'm sure that the more you turn this bolt more deeper goes the piston inside the valve. I've testeded on mine this weekend!
If this have any impact I can't say for sure. People say that has not any effect on idle.
Nick
Found the breather pipe that connects the crank case to the swirl pot had split in half. Now replaced (2nd breather hose in two weeks) and it seems good, not cuts out on a test run.
Also gave the ICV a proper clean out. It wasn't too bunged up though.
Oh dear, I was wrong, driving it in traffic earlier and its worse than ever. Cut out about 10 times in a short journey. Then I got very p155ed off with a women throwing her arms around in the car behind me whilst I tried to restart, once it fired I dropped the clutch at about 6K RPM - lots of smoke from a burnt clutch, hope I have not ruined that just for a moment of frustration.
Iv a feeling its heat related...need to check after the weekend, I am in Birmingham now, going to the British GP Qualifying and Race this weekend :) Had to drive up in the Polo though :(
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