Punto 1.2 Active Sport uneven idle

My girlfirends Punto started having an erratic idle. I have changed the spark plugs and air filter. Since then, the engine now holds revs after about 7
miles of driving. It either idles hunting between 800-1200 revs or holds at 1500. If it does come down to 800 it then stalls. The revs are held at 3000 when you come off throttle. I'v checked the throttle cable, lubricated it and its not sticking. I've also cleaned the stepper motor out with WD40 hoping that would cure it. The engine when under load is fine but when you are feathering the throttle it runs lumpily and the car is jumpy. I took the car to Fiat, they checked the ECU for fault codes and there was nothing stored. They flashed ECU with an update of software and it didn't do anything to help out. Please would someone point me in the right direction as to how this is caused. Thank you
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Totally remove the throttle cable so the throttle can be freely rotated by hand.
Gently move end stop to end stop (especially at the nearly closed end) feeling for any drag, snatching etc.
The other possible cause is that the ECU which is self adaptive has got itself all confused and needs retraining.
The sequence (from memory) is as follows:
1) Disconnect battery for 30 minutes 2) Reconnect bat. 3) Start car and allow to idle till fan cuts in 3 times 4) Rev car at a steady 3000 rpm for five minutes 5) Release throttle and allow engine to idle for 1 or 2 minutes 6) Switch off
Please report back how you get on.
Nick /////

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
in article 45158687$0$3617$ snipped-for-privacy@ptn-nntp-reader04.plus.net, Nick ///// at snipped-for-privacy@Xnick-bailey.co.uk wrote on 23/09/2006 20:09:

Excuse me for jumping in a hijacking this ... Does this procedure apply to the MK1 Sporting, too?
Our second Sporting is nothing like as quick as our first one. I have disconnected the battery for 15 minutes and reconnected, but there's still an awful flat spot in all gears and it _feels_ like the flat spot ends when just lifting off full throttle, but if the throttle is only opened that far (to just near open throttle) it's still very poor. I had wondered if the ECU had got confused and was pretty much only allowing a very narrow set of fuelling instructions.
Paul
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote on 23/09/2006 20:09:

with that. Our MK2 (2003) has the same annoying feature, while our 2000 model has not. It seems the E.O.B.D-system (Electronic On Board Diagnostics) is responsible for this kind of behaviour. Also the "improved" environment protection unit has something to do with it. At least that is what someone once told me. Maybe there is a ECU-update for your car, I don't know for sure. But maybe Nick has a different vision on this subject. If so, I would like to hear as well. Ciao, E-Cie.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
in article 4515af1a$0$28499$ snipped-for-privacy@nova.planet.nl, E-Cie at snipped-for-privacy@shutup.au wrote on 23/09/2006 23:03:

Both the Sportings are MY 1999. AFAIK, resetting the ECU was as simple as disconnecting it for 15 minutes. The ECU would then "learn" as you drove it, but this procedure does make sense.
Paul
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Well 1st reports look promising for our Punto friend.
In terms of environment protection and ECU settings I totally agree.
My 02, Euro 4, Stilo Arbarth suffers from pinking/detonation. Fiat agree yet refuse to do anything about it.
To reduce detonation there are two methods. 1) reduce ignition advance and 2) increase fuel delivery. Both of these increase emissions. My Stilo has two "knock" sensors, both work and both signal detonation. Both retard/modify fuel quantity but NOT enough. Fiat have basically ring fenced the ECU map.
I have my findings and concerns loggted in writing with Fiat and there will be hell to pay if and when I suffer engine damage. I expect 200,000 miles out of my Stilo engine ! :-) I have considered having the ECU remaped but to do this would possibly negate any claims against Fiat so have not gone down this route.
Nick /////
wrote on 23/09/2006 20:09:

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote on 23/09/2006 20:09:

at my Fiat-dealer, I saw a Stilo with a blown engine; looked like the1st piston totally smashed it. I don't know the mileage, neither the cause, but I'm willing to ask if you are interested. I don't want to upset you, though...;-) Ciao, E-Cie
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Can't promise anything but it may help. I think all Bosch / Hitachi / Marelli are self adaptive and can become unsettled. Running the procedure will not do any harm.
If your sporting is single point injection then there is another visible fuel check you can make. Remove the air filter so you can see directly into the throttle body. Start the car and look into the top of the throttle body. You should see mists of fuel being injected into the body. Now operate the trottle and the fuel should flow more and still be well misted / spray and not jet like. Difficult to judge but play a little reving and watching.
You can also us a ver small dental mirror to inspect the injector to see if you can see any fuel resin deposits on/around the injector head.
If you are in any doubt the run some injector cleaner through the system.
Nick /////
wrote on 23/09/2006 20:09:

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
I have carried out what you have advised me to do and after taking the car for a run down the dual carriage way, so far, all looks well. Thank you for your help, I will get back to you if this doesn't cure the problems and hopefully you'll be able to help me furhter. Again a big thankyou
Nick ///// wrote:

--
Message posted via CarKB.com
http://www.carkb.com/Uwe/Forums.aspx/fiat/200609/1
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Well this sounds good and I'm pleased for you. Hopefully the solution will last for a good while.
I do hope it lasts.
These sort of problems are so difficult to diagnose, let alone fix, that any experience of advice from any quarter is well worth noting.
Fingers crossed.
Nick /////

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.