General Fast Idling Uno 1.1iES

[Leon1.1]

My 93 L reg 1.1iES has recently had a new vacuum advance unit fitted...and tube connecting the unit to the injection unit. However the problem of it idling too fast has not been cured sometimes the idle will drop, but mostly it is around the 1100rpm. If I remove the large block connector from the right hand side (looking from front of car) of the injection unit which controls the stepper motor, the idle falls to a much more reaonable speed. I haven't tested it on a run too see if perfomance is affected removing that connector.

I have already as stated replaced the vacuum advance and vacuum tube, I will check the tube again to ensure it isn't fracturde anywhere.

I have also reset the ECU by removing battery for 30 mins and then reconnecting......this sometimes seems to rectify the problem for a short time then idle speed increases once more.

The connector and contacts apeear clean enough and the stepper motor does engage when the connection is remade.

Performance also seems to be reduced from when I had first put the car back on the road.

Is there any possibility that the timing could have this effect as I had adjusted it and it seems to run smoothly enough. However, the last person to do the timing had it 180 degrees out yet it still ran quite well.

Any ideas would be very much appreciated.

Thanks In Advance,
Leon.

 

[Morty Mort]

Look on the rear of the injection module (SPi). On the rear left where the accelerator cable "thing" is, there should be a little plunger supposed to be depressed when you put your foot of the gas. If it isn´t depressed, the engine will get too much fuel (twice amount) when idling. This can be caused by a too tight accelerator cable. If your is, loosen it, to make it hit the plunger.

I know what a stepper motor is , but where is it and what does it do to the engine?

And the ECU is reset by disconnecting the battery which you have done for some time. Then reconnect, start the engine and let it idle until fan cuts in. Shut off engine. ECU is now reset.

Morten.

 

[Leon1.1]

The stepper motor is located on the lower part of injection unit...the plug is the big 4 pin black one on the right-hand side (from in front of car) of the injection unit. When this is unplugged, the idle drops right down however as soon as this is reattached, the idle increase.
Also if I disconnect the vacuum hose to the vacuum advance unit the idle falls to a more normal speed.

I plan to shorten the hose to vacuum unit as replacement was a bit too long and so may be compressed by the vacuum passing through it..then I'll reset ECU and see if that helps at all.


The related problem is now that on gear changes, the engine is revving when clutch is dipped and foot off accelerator..ie revs not dropping fast enough.

Any other suggestions much appreciated!
Thanks in advance,
Leon.

 

[Louie Bee]

Fixed Fast Idling Uno 1.0iE

Hi Leon,




My 93 L reg 1.0 iE had the same problem til 2 days ago (engine was racing at lights worse with no throttle and the clutch in).



[Before I found fiatforum I recently fixed the air cleaner thermostat in position which had been flapping around since I bought her. I did this by wrapping a piece of electrical tape around the fixing bolt under the notched plastic spacer. Looks like someone forgot to fit another piece some time ago. The air flap thingy it controls also snapped off (just my luck). I managed to hold it together with a small screw, and the flap lowers when boiling water is pored over the thermostat, and lowers again when with contact with ice. - Not much if any noticeable change].

I Cleaned the SPi and put a new air filter in and gained a lot of power! But at the lights, the engine still was racing.


I found fiatforum and looked into similar problems.



The idol switch plunger was being struck on the throttle (good accelerator cable adjustment) thanks Morten.



The Vacuum advance and pipe were good order – looks like it has been renewed about 4 years ago and can only suck on the throttle body’s end for a bit till it holds a vacuum on the tongue.



Morten, thanks for the ECU reset info – that is a real gem.



During ECU reset while idling till the engine until fan cut in, I nudged the stepper motor plug lead and the revs suddenly dropped to how it used to idol (thanks for the guidance Leon). As I let go, the idol speed became intermittent. This lead also goes to the lambada sensor, and after giving this part of the loom some slack the problem has been rectified.



I think that there was a bad connection to the lambada sensor or the stepper motor as these are the only connections on the part of the loom I moved. Not sure if there was a short circuit somewhere (bad cable shield inside loom), or an open circuit (bad connection or snapped wire).



Leon if you have not got to the bottom of it, it may be worth checking the connection to the lambada sensor, and its operation. I am no expert but it is working for me.



Good luck!

Louie Bee.