Intermittent misfiring in Fiat Siena

vignaraj · New Member Joined: 18 Sep 2007 Posts: 3

Hi,
I have Fiat Siena fitted with LPG (open loop system). There is misfiring in the vehicle, however on board diagnostic light doesn't light up. Engine analyser also is unable to detect the error.
Mechanics opine that it is "ECU" failure which I personally doubt.

Please advice..
Vignaraj

Arun Sivanand · Posted: Tue Sep 18, 2007 12:50 pm Post subject:

Dear Vignaraj,

Please service the LPG Kit and also try to check on the Coils and the primary signals,

If you have a diagnostic equipment can also check the data stream for further information,

Preliminary checks like spark plug condition, confirmation on your timing and the condition of your valve guides etc and the feeling of power when there is no misfire needs to be checked too,

Regards,
Arun
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vignaraj · New Member Joined: 18 Sep 2007 Posts: 3

HI, Thanks for the quick reply...
this is how the story goes.. Travelling at 40kmph. vehilce dies down totally..sudden stalling. restarted the engine.. misfiring started..
checked all possible visible things.. drove down to residence....parked for one week due to lack of techinicians. started today morning.. heavy misfiring..clanking sound from engine.. total engine die down. restarted after 2 hours.. engine starts... slight misfiring.. engine raised.. suddenly the engine seems to be normal and perfect for driving.. vehicle taken to workshop around 15km.. engine analyser test shows all negative.. and mechanics opine "ECU" problem. Sparkplugs, cords, coils etc all normal... however, I personally feel 2nd cylinder is getting less current than required.

Please help..
Vignaraj

Arun Sivanand · Posted: Tue Sep 18, 2007 1:27 pm Post subject:

Dear Vignaraj,

Issues with ECM's are usually not inermittent, however there are rare chances,

There could be a possibility of a blockage or a bad earthing which could be inspected. Also please check the cam and crank sensors.

The recommendation is to get it checked by a Diagnostic Scanner as some intermittent faults may not be highlighted by the MIL (check engine lamp).

Also, do update your profile in the forum with more details and do mention more details of the car, including the VIN no:, yearof make, and if possible the ECU make as well.

This can help people understand better about the car;

Regards,
Arun
_________________
Should you need any assitance in Operation and Use of the X431 Please feel free to clarify them with us as per convenience

vignaraj · New Member Joined: 18 Sep 2007 Posts: 3

Hi Arun,
will surely update the details..
The test was done on Diagnostic Scanner and the test was unclear.
Will have to check the sensors as mentioned by you.
Is there any quick way to check that?

Regards,
Vignaraj

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