Technical Any help would be great

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Technical Any help would be great

topgear7

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Mar 10, 2015
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hi everyone I am hoping someone can help me


car : fiat panda


work already done : coil packs , leads , spark plugs, throttle body cleaned , sensors cleaned


problems still with car : rough idle , misfiring , high fuel consumption


rpm go themselves at some points , when fuel is low the rough idle is even worse , pushing accelerator removes the rough idle

No engine management light on and no codes showing the last code was p0351 ignition coil a primary / secondary circuit malfunction

No one can seem to shed any light on it been told so many different things

any help would be great many thanks
 
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Hello and welcome.

Can you give some more information on the car please? Engine size, year and how long you've had it.
 
If you can, with your diagnostic scanner start logging from a cold start.

Check the Fuel System Status.
That it is going from Open Loop to Closed Loop within a few minutes of a cold start (in the morning)

(I suffered with it tripping into Closed Loop - System Fault due to the upstream O2 sensor failing to heat quick enough, all without a code or engine light with similar problems, misfire, bad idle and self reving, bad mpg etc, new O2 sorted that out)

Check the coolant/engine temp.
It should rise in relation to the warming engine.

Check it logs an accurate RPM signal, shows the crank speed sensor is working.

Check the ignition angle/ignition timing %.
This should alter as you increase and decrease the rpm to show the Cam sensor is working.

Once warm (and in Closed Loop fueling)
Log and compare both O2 sensors.
Bank 1 Sensor 1 is the upstream or pre cat
Bank 1 Sensor 2 is the downstream or post cat.

Sensor 1 should switch every second if you hold a steady 1500-2000 rpm.
It should peak at 0.9v and trough at 0.1v with it's average at 0.45v for perfect fueling.
Any other reading may suggest a sensor problem, but do not write off an air leak somewhere.

Sensor 2 reading will depend on the heat in the cat, so it's hard to say what it should read, but it should NOT mirror Sensor 1 (if it does the cat is fecked) It should kind of smooth out what Sensor 1 is doing, so there should be little peaking and troughing.

There should be some reading above 0.1v to show it's working.

An additional thought. does the fuel pump "whine" for a second of two when you switch the ignition on?
The whine should come from under the back seat area.
 
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