Hi Friends,
I own uno 1.0 i.e with BOSCH SPI. Always engines revs in high speed. As suggested in older posts I have tried to fix this by turning the distributor slightly. Problem did not solved. When turn the key on, step motor attached to throttle body is not working. How to find out whether the step motor is not working. here no throttle bodies to find out. Any thing I can do to bring down the idling speed. now consumes more fuel. Any help please.......?

One more thing. When the engine stops shaft of the step motor (which pulls the throttle cable end valve) is partially pulls the value(may be the butterfly valve). if it goes completely in side it will reduce the speed. How this can do?

Chamitri said:

Hi Friends,
I own uno 1.0 i.e with BOSCH SPI. Always engines revs in high speed. As suggested in older posts I have tried to fix this by turning the distributor slightly. Problem did not solved. When turn the key on, step motor attached to throttle body is not working. How to find out whether the step motor is not working. here no throttle bodies to find out. Any thing I can do to bring down the idling speed. now consumes more fuel. Any help please.......?

Click to expand...

I am not too sure about some parts of your message but I'll try to go in parts.

1) From my experience, I also had high idle and to fix this I've done two things:
a) reset the ECU - disconnect the battery for 10 mins with the engine at normal working temperature and then reconnect, start the engine and run in for 2 mins at approximately 2000 rpm. There's a procedure somewhere in this site
b) replaced the lambda (or oxygen) sensor in the cat converter

2) You do have a throttle, it's hidden by the airbox. However to test if it is working do the following. With the car cold, ask someone to turn the ignition on. When doing so, you should see the stepper motor moving. If it doesn't bad news

Now, you could also have the air temperature sensor too old but generally the way it ages it leads to poor start when cold.

Hope this helps,
Afonso

thanks for u'r valuble advice nunesaf.
I have checked the stepper motor as U said. always it keeps by pushing the butterfly valve. When some one depressed the throttle fully i pressed it by the finger. then stepping noise herd.
I have reset the ECU. But it did when he engine is cold.
If the stepper motor doesn't work means it needs replace isn't it?. Its a really bad news. Here sri lanka no any such spares to find out. Even in e-bay no throttle bodies. I think only option is replacing it with a carb.
thanks again nunesaf. any of guys can help me to find out throttle body please? I think stepper motor cannot replace along.
If the connection between ECU and Throttle removed what will happen.? (sorry for silly ques)

From what you say, it suggests the stepper motor is actually fine. But please confirm that you’ve noticed movement in the stepper motor when you’ve turned the ignition on. I really want not to give you misleading information.
Re-setting the ECU will do a massive difference when the car is hot – at least that has worked for me. So keep your hopes there!
Indeed a high idle could be due to a bad injector (I presume that’s what you mean by throttle body). You can always remove it and get it cleaned. Just be careful don’t break anything.
There’s also some people reporting that a throttle cable that is too tight leads to a high idle and there’s mention to a plunge thingy but I’ve personally never seen that in my car, my fault surely.
Answering your questions:
1) You can replace the stepper motor independently from the injector unit (not an expensive item) and it is compatible with lots of other cars (fiat bravo?)
2) I presume you are referring to getting rid of the electronic fuel injection. Don't really know what will happen, but I think your cat converter will soon dye as the carb is quite undisciplined regarding the emissions

Thank you very much for your valuable advice.
I have reset my ECU when the engine is hot. It works. Now idling speed has came down. Today I have drive couple of kms and up to now OK.
I have checked my stepper motor and it seems to be work.
Couple of days ago I have speed up the car on a high way for 125km/hr and after that had a problem with ignition module. Don't know whether it has messed up the thing.
How ever I think resetting ECU when the engine hot is a good solution for high idling, At least two of us got the advantage on that no?
Here in Sri Lanka no spares for UNO's. If I had to find out stepper motor only way is E-bay. But those are expensive for us.
Thanks again Afonso

Hey well done .

Hi All,
Really sad news. Again same problem came. Now high idling.Even with out touching the gas pedal vehicle can drive. This is really headache due to lack of spare parts in Sri Lanka.
I have check the injector by removing the air filter box.. It also seems to be fine.
I think I have to check the lambda sensor. I have seen guide on checking it. But little bit confusing me. Meanwhile could any one can tell me how to check the ECU. Is the lambda sensor using on UNO 1.0 i.e is same with punto or not?.Any one can help me guys?
If one plug not sparks properly can this happened?

Chamitri said:

Hi All,
Really sad news. Again same problem came. Now high idling.Even with out touching the gas pedal vehicle can drive. This is really headache due to lack of spare parts in Sri Lanka.
I have check the injector by removing the air filter box.. It also seems to be fine.
I think I have to check the lambda sensor. I have seen guide on checking it. But little bit confusing me. Meanwhile could any one can tell me how to check the ECU. Is the lambda sensor using on UNO 1.0 i.e is same with punto or not?.Any one can help me guys?
If one plug not sparks properly can this happened?

Click to expand...

To change back all the sudden, maybe you could revisit the parts that were affected when trying to discover the problem. I think you are already dispersing your focus and looking everywhere.


1) Some poor electric connections? Follow the lambda sensor wire and you will find two connectors - one is for the heater component (2 mini connector) and the other one actually carries the signal (round rubber look).

2) To properly test the lambda sensor, but you can do something like this:

Just wire the negative of your multimeter to the ground and the positive to the signal.
Alternatively, have a look at this 5* writing:
https://www.fiatforum.com/uno-guides/28442-how-produce-lambda-sensor-tester-yourself.html

3) Is the accelerator cable properly adjusted? When idling, is there any slack it in at all?

4) To test the injector, I am afraid that such sort of visual inspection is not enough. But I would leave the injector alone for the moment.

5) Don't have any idea of how to check the ECU. These units are quite strange, no documentation at all on the web (all I could find was a document in Polish..). Until you do the basic tests, don't touch on advanced things such as the ECU

6) A poor spark plug would give you rough idling and low revs actually.

Hi,
Thanks for taking the burdens Alfonso.I am really fed up with this car. continuous repairs. Front whole suspension, radiator, brake,... now fuel system.:bang:.
01. With the help of your valuable guide I have test the Lambda. It seems to be OK.
02. I have remove the injector housing and with the help of contact cleaner cleaned it. There were some deposits on it. I was unable to remove the injector from the housing (cylindrical one).
03. Still idling is high. Evevn when driving on 3rd or 2nd gear once the accelerator pedal release engine is knocking.
04. There were no any slacks on the accelerator cable.
05. Vaccume advance unit connecting tube got blocked near the manifold and it cleaned.
Still the problem there.
any suggestions please?
05.

Well, the last thought would be for you to test the static advance (the vacuum advance unit is responsible for the dynamic). This is done with a timing light or strobe light. And I'm afraid this is the end of my scarce wisdom. I hope you get this sorted!

Hi Alfonso,
Thank you very much for your valuable advices. Those really help me to come to and end. Will see some one can help me on this timing issue.Thanks again alfonso

Back from the dead, but here is my addition.

I have the same problem, what i do is this:
First of all i have the problem, IF the ecu is reset.
E.x. removing the battery, for seconds, then i have 1500-2000rpms idle.
And it doesnt let me push the throtle plate down.
What i do next, is this:
I tune my ignition advance very low, the ECU calibrates after 1-2 days
Then i crank the ignition advance in normal, and then its ok.

I have another side effect, whatever sparkplug i put, it breaks my NO1 spark plug positive porcelain.

NGT said:

Back from the dead, but here is my addition.

I have the same problem, what i do is this:
First of all i have the problem, IF the ecu is reset.
E.x. removing the battery, for seconds, then i have 1500-2000rpms idle.
And it doesnt let me push the throtle plate down.
What i do next, is this:
I tune my ignition advance very low, the ECU calibrates after 1-2 days
Then i crank the ignition advance in normal, and then its ok.

I have another side effect, whatever sparkplug i put, it breaks my NO1 spark plug positive porcelain.

Click to expand...

Hi,
Thank you very much for reply even for a old thread.
My high idling issue is due to worn butterfly valve sensor. Still the problem is there and no spares to find out. I'll use it as far as I can and then try to find out carburator( In my country UNO spares are very very rare. Now only three persons are selling some spares)
However I have tried your suggestion also. Unfortunately it didn't work.
UNO is a really pretty car and I like it very much. But so much of difficulties to keep her updated.
Thanks again mate.