Chuggy 18 year old C3

HillStreetBlues

Friend had a C3 that is sometimes chuggy in the morning. Once needed a jump start, was still chuggy but when engine was switched off and straight back on again it was fine ( which seemed odd).
Would a cheap ebay OBD2  scanner show the fault?

Mildly_Miffed

HillStreetBlues said:

Friend had a C3 that is sometimes chuggy in the morning. Once needed a jump start, was still chuggy but when engine was switched off and straight back on again it was fine ( which seemed odd).
Would a cheap ebay OBD2  scanner show the fault?

It'll show the fault codes that are stored.

That might or might not point you straight to the cause of the issue. A good service may well help.

Is it petrol or diesel?

Goudy

A cheap OBD2 scanner will report any generic fault code from the powertrain/engine ECU.

Generic codes are used by all manufacturers and generally mean the same between them all, but not always.

Manufacturers also use their own, specific codes for certain things.
Plus there are other ECUs within the car, like SRS, ABS and body control.
You won't read any of these with a cheap generic reader.

Fault codes are either hard written or pending.
Hard written codes will light up the EML on the dash.

Pending codes are waiting.
It might detect a fault once or twice, then wait to see if it happens again in the same drive cycle.
It it does detect it again, it'll set the hard written code/EML, otherwise it'll pend it for x amount of clear drive cycles.

What a cheap generic reader should be able to do (depending on software used) is read and log what all the engine sensors are doing, which can help detect a problem.
But this relies on you knowing what you are looking at and what to look for.
If you don't know what normal is, how do you know what isn't.


If it's chugging at start up it sounds like it's firing up on three cylinders, but knowing if it's petrol or diesel will help.

HillStreetBlues

It's a petrol.
While it's happening the engine dashboard light stays on, I know the spark plugs have been changed fairly in the last 6 months.

Goudy said:

If it's chugging at start up it sounds like it's firing up on three cylinders, but knowing if it's petrol or diesel will help.

That;'s was my thoughts, but couldn't work out why a quick restart would clear the issue.  I'm very old school with cars and know nothing about computer managed systems. I did wonder if it could be a faulty sensor or fuel control management issue?

Arunmor

When last were the distributor cap and HT leads (and rotor arm) changed or connections cleaned?

If not that you need at the carburettor and/or fuel filter.

Goudy

Some faults will clear when the ignition is switched off and on again.

Others will set the eml until they are cleared with a diagnostic tool.

If it's only firing on three it's probably an ignition issue like that coil pack or a fuel problem, like an injector.

Mildly_Miffed

Arunmor said:

When last were the distributor cap and HT leads (and rotor arm) changed or connections cleaned?

If not that you need at the carburettor and/or fuel filter.

An 18yo car is 2006, not 1976.

It won't have ANY of those components, except for the fuel filter...

Ibrahim5

and the HT leads.

Goudy

This might be relevant.

 C3 misfire issues - French Car Forum

and see post 7 by glenandemm here
Citroen C3 screen washer problems — MoneySavingExpert Forum

Mildly_Miffed

Ibrahim5 said:

and the HT leads.

No, no HT leads fitted.

It has a single coil pack which connects directly to the plugs, like almost everything else built in the last third of a century or so.