Citroen C3 1.1 hard to start

[omglol]

Hi!

I've got problem with Citroen C3, make year 2002, engine 1.1, code HFX. The engine usually (8 out of 10 times) starts very very hard, taking a lot of cranking to fire. When it finally starts, it runs completely normal and has full power.

Here's what we've done so far:

- changed air temperature sensor (the old one showed -30C or something)
- changed coolant temperature sensor (similar problem as above)
- changed spark plugs
- changed fuel pump
- changed crankshaft/engine speed sensor

Everything on the list above is new, but the problem is still here ... does anyone have an idea where to look next?

[Meat-Head]

lift back seat, put direct battery power to the fuel pump see what happens.

change fuel filter first

[omglol]

Already tried direct +12V to fuel pump, same problem. Fuel filter was changed.

Also forgot to mention - car has only 60,000km (real, not IN-corrected) - owner bought new car.

[oldford]

How are the readings for the intake and coolant temperature now? Because I have seen ecu's that set the temperature at -30 or -40 when the engine is off.
One would not expect the engine to run fine and with full power with those kind of readings.
What are the readings of he map-sensor? With ignition on and engine off, during cranking and when idling?

Can you do a 4-gas test at the cold start?
What are the numbers?
What's the fuel pressure at the cold start? Just before and during cranking and when the engine runs?

[omglol]

Air/coolant temperatures are OK now.

MAP readings:

engine off: around 750 mbar
cranking: 810-840 mbar, in rare case up to 900 mbar
idle speed (@750rpm): 420 mbar

There is no fuel pressure sensor on this car, but fuel pressure is 100% OK ... fuel pump and fuel filter are new, also car has full power when it runs.

[oldford]

Map is way, way off.
With engine off you would need around 1000 mbar depending on the weather and the elevation you are.
Check the weather reports on internet for an exact reading.
However, the signal is very erratic. It should not go higher when you start cranking compared to engine off.
I seriously doubt if you have full power. For that you need a map value of around a 1000 mbar at sea level.
Check map sensor voltage supply (5 volt) and wiring.
What is the rare case where the map sensor goes to 900 mbar? When you press the accelerator or just during idling?

Even with a fuel pressure sensor, you could still measure it the old fashioned way with a gauge.
If a fuel pressure gauge is not available you can even do it with an oil pressure gauge, preferably a mechanical one, but it is possible with electrical ones if you have a matching gauge.

[omglol]

MAP is OK. I found out that reading at engine off is actually last stored value of MAP before you turn off the engine, so it changes everytime you start/stop the car.

Fuel pressure is also OK.

[Turbo5GT]

i would also check if the O2 sensors are working right, they can make the car run rich, unplug and start without them.

[Meat-Head]

Hang on,

OFF TOPIC - BUT RELEVENT:-

There a rumor going around that states Honda's have a SIMULAR problem, the cat 'blocks' when cold, but when given boot full ok.

Just with oldford saying map readings way off.

can you

1) Remove cat repreat experiment with map
2) damm, remove cat anyway

[Ashraf6119]

Hi

Have you checked the Cam Timing if its not out..........Also do a Cylinder Compression Test............

Also have you tried start it with booster pack connected to the battery..........it could be your starter motor is poor and causing a voltage drop to other sensors..........worth trying

The fuel pressure regulator is in tank build in fuel pump

[autoelectric]

Sometimes happens the plug of engine speed sensor go faulty.
Try moving the plug while car is cranking.

[ninja123]

you need to find what is missing when cranking and not starting.

Check all live readings, engine speed, coolant temp, air flow/map, monior both O2 sensors in graph form and compare with a good reading.

Faulty bank 1 sensor can cause under or over fueling, you can see this with fuel trim (short term) on cranking.

Pull out spark plugs and check condition of tip.

I would also suspect a melted cat convertor, due to the fact that you had a faulty coolant temp sensor, engine would have been running very very rich which if not caught early, almost always end up melting the cat.

remove bank 1 o2 sensor and try starting then.

ninja

[electrones]

hi friend

I agree with ninja123, you need to find what is missing to get the engine running, but disagree that O2 sensor makes it difficult to start the engine, knowing that at startup the mixture tends to be rich and this time the loop is open and the sign of O2 sensor is ignored by the ECU. So I think it should concentrate on the air intake system (map sensor), vacuum system leaks, ignition system, fuel system and measure the resistance of the player keys,some of these systems may be failing, good luck. ;)

[PierreTheron]

Wait a minute .

Is this not the engine that sucks up some water in the wiring harness all the way to the ecu plug .

Have you checked for some green stuff at he ecu connectors??

[omglol]

No, I did not. I will when I get the customer back.

[omglol]

Today I took used ECU and copied 29F400 from original ECU to the used one ... nil poi. Same shit.

[Meat-Head]

ok, swap the 29f data from the used ecu & keep your eeprom.

if in the flash, you just copied it across

[omglol]

Sorry, what do you mean? The ECU does not have EEPROM, only flash memory.

[electrones]

Hi friend

Check capacitor to ignition coil, mounting bolt
Good luck, -_-

[omglol]

Tried disconnecting oxygen sensors - no luck.
Tried changing relay module in engine compartment - no luck.

However ... strange thing is that I hear relays (in relay module under hood) clicking during cranking. I am starting to think the ECU does not get steady power supply during cranking.

Can someone provide me ECU pinout for this car? I have Autodata, but it does not have full ECU pinout, only wiring diagram.

[omglol]

Hi friend

Check capacitor to ignition coil, mounting bolt
Good luck, -_-


Does not have it and never had one.

[Meat-Head]

noo eeprom, weird.

batrery to body earth?

[omglol]

Fitted different (used) starter with 4 brushes instead of two (more rpm) - fires every time like hell. ;)

[PierreTheron]

Hi
So what you saying to us .
You need to be next to the vehicle to have a feeling on what the fault might be . So no need to check on dk and connect the car to the trouble shooter diagnostic cable . You might have a wrong direction off trouble shooting it DK way ..???
:egg:

[omglol]

Say what? Years of experience, never came across such a malfunction.

To the "ears", the starter was turning engine completely normal ... completely! That's why I checked for 300 other probable causes ... I would never think the starter was causing problems ... I had one similar (used) and I tried fitting it as a pure guess ... I did not know what to do anymore ... and bingo!

[jnoroeste]

Hi M8,

Make sure your car starts always when you are using second battery, seems engine ecu locks by low voltage when cranking.

Regards.