jackwhoo said:

Certainly on carb engines a blocked air filter can cause excess fuel to air ratio.
On fuel injection engine the air intake is measured(or calculated) and ecu calculates how much fuel to add . So a blocked air filter can reduce the air flow but the ecu is still "told" the actual air flow so does not add excess fuel.

I looked for ops other posts and couldn't find any ?

Best wishes
Jack

Click to expand...

Sorry I was getting confused with another poster from

11-01-2020 2004 Panda 1.1 active - Whining issue?

Ricardogalpini said:

OK I will do tomorrow morning

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jackwhoo said:

It definitely is not entering closed loop at idle,
The constant voltage signal from the o2 sensor is confirmation.

Off idle it can enter closed loop as o2 signal goes high and low. Plus passes emissions test at fast idle

The hydro carb count in the emission test report are not so high as to suggest a really bad misfire.

excess fuel at lidle

Interesting

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ahh missed that post. Thats the reason for the High CO


just need to find out why. Surly it got to be a sensor. Surprised an error code doesn't pop up.

most things to check have already been changed. Things like the CAT or air filter should be worse the higher the revs. Wouldn't do any harm to temporary remove and rescan the o2 sensor but I don't hold much luck

something on the back of my mind thinks this has turned up before. 90% sure open loop and CO turned before. Got an feeling maybe 75% it was throttle position sensor or throttle peddle sensor.


try and search a bit later on if nobody's found it first.

Throttle position sensor seems to work as at idle reads 0 and increases as put foot down. Air filter is clean and car was serviced 6 months ago with only 1000 miles since service.
I will post full scan pictures in morning

Ricardogalpini said:

Throttle position sensor seems to work as at idle reads 0 and increases as put foot down. Air filter is clean and car was serviced 6 months ago with only 1000 miles since service.
I will post full scan pictures in morning

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I'm still thinking possible leaking/dripping injector. My thinking being
At idle ecu has trimmed the fuel down to its lower limit and can go no leaner.
Off idle the drip /leak has less effect as there is more air flow .

But things are usually more complicated than this!

If it was possible to read the long term fuel trim at idle and result was feasible (sometimes getting reliable info from ecus isn't easy) that may help.

Anyone know what maximum long term fuel trim adjustment is For this fiat ecu?

Please see obd2 images with car cold (black car facing into the sun)
Looking for plug removal socket now.

Don't have small plug socket, it's daughter's car and my plugs are bigger.
I will post live running diagnostic pics soon

15C
59F

seems about right. Thats read from the MAP which has already been changed


Can you check the coolest level ?


put your hand over the exhaust. See if pressure builds up.

Obd2 live data readings when first start car.
As can be seen TP(throttle position) =0% and 1st stage lambda (02) =9v non fluctuating

Sorry 0.9v

After a few mins and TP at 8.6% & fast idle the 02 sensor is fluctuating between 0.04 and 0.8v.
However as soon as I remove pressure on the accelerator back to steady 0.94v

koalar said:

15C
59F

seems about right. Thats read from the MAP which has already been changed


Can you check the coolest level ?

Click to expand...

Etc is engine coolant temperature
Read from coolant temperature sensor

Iat is intake air temperature read from intake air temp sensor(often part of map sensor)

This one shows ECT (engine coolant temp) 5mins in at 188 at fast idle.

Short term fuel trim reading at idle mainly at -100% and every 40secs or so increasing to -60-70 for a couple of secs and back to -100 at idle at fast idle goes up to 0% and slowly levels out if held steady at a % relevant to throttle position
Long term fuel trim is -100 at idle and does not change at all. Then at fast idle will change for a fraction of a second but returns to -100 immediately and stays there no matter what throttle position is.

koalar said:

ahh missed that post. Thats the reason for the High CO


just need to find out why. Surly it got to be a sensor. Surprised an error code doesn't pop up.

most things to check have already been changed. Things like the CAT or air filter should be worse the higher the revs. Wouldn't do any harm to temporary remove and rescan the o2 sensor but I don't hold much luck

something on the back of my mind thinks this has turned up before. 90% sure open loop and CO turned before. Got an feeling maybe 75% it was throttle position sensor or throttle peddle sensor.


try and search a bit later on if nobody's found it first.

Click to expand...

Any luck finding the other post?

should have looked at the First Post correctly. Its probably running okay.

it has also failed at fast idle

lambda is correct so fuel mixture is correct.

I would take it for a run and keep the revs High. You don't have to drive mad. Just leave it in a higher gear than normal for about 15 minuets. clear the rubbish out of the system and evac


this car passed without any work being done


GARAGE 1
Fast idle CO - 0.06 (0.20) PASS
Fast idle HC - 20 (200) PASS
Fast idle Lambda - 1.014 (0.970 - 1.030) PASS
Natural idle - 1.36 (0.30) FAIL

GARAGE 2
Fast idle CO - 0.063 (0.200) PASS
Fast idle HC - 50 (200) PASS
Fast idle Lambda - 1.004 (0.970 - 1.030) PASS
Natural idle - 5.430 (0.300) FAIL

Ricardogalpini said:

Short term fuel trim reading at idle mainly at -100% and every 40secs or so increasing to -60-70 for a couple of secs and back to -100 at idle at fast idle goes up to 0% and slowly levels out if held steady at a % relevant to throttle position
Long term fuel trim is -100 at idle and does not change at all. Then at fast idle will change for a fraction of a second but returns to -100 immediately and stays there no matter what throttle position is.

Click to expand...

Everything you have posted
Points too excessive fuel is going into cylinders at idle, so much the ecu has reduced the amount of fuel to the lowest limit programmed and the o2 sensor is still reporting fuel rich mixture( 0.9v )


Can you remove the fuel rail with the injectors still attached and the fuel feed pipe still attached?

Does the car have a fuel pressure regulator attached to the fuel rail? Or is the fuel pressure regulator part of the fuel pump?

This is the Haynes manual paragraph

Ricardogalpini said:

Any luck finding the other post?

Click to expand...

yes there loads. But its not what happening here. I thought you only had a problem at idle. Just Google idle, throttle position sensor, mot and emissions. But to me is a red herring as its also failed at fast idle and the lambda is bang on where it should be.


So you have the correct fuel to air but still High CO but HC are okay. The normal "fix" is to get the CAT red hot before the test.

jackwhoo said:

Everything you have posted
Points too excessive fuel is going into cylinders at idle, so much the ecu has reduced the amount of fuel to the lowest limit programmed and the o2 sensor is still reporting fuel rich mixture( 0.9v )


Can you remove the fuel rail with the injectors still attached and the fuel feed pipe still attached?

Does the car have a fuel pressure regulator attached to the fuel rail? Or is the fuel pressure regulator part of the fuel pump?

Click to expand...

you done the same as me


the fast idle has also failed just doesn't have a circle around it


lambda is Bob on. mixture is correct. So CAT isn't doing its job. Clogged or not hot enough

Do you have an IR thermometer? The catalyst burns excess HCs. The outlet should be hotter than the inlet. If it's the same, the cat isn't working.

Wikipedia says -
Damage
Catalyst poisoning occurs when the catalytic converter is exposed to exhaust containing substances that coat the working surfaces, so that they cannot contact and react with the exhaust. The most notable contaminant is lead, so vehicles equipped with catalytic converters can run only on unleaded fuel. Other common catalyst poisons include sulfur, manganese (originating primarily from the gasoline additive MMT), and silicon, which can enter the exhaust stream if the engine has a leak that allows coolant into the combustion chamber. Phosphorus is another catalyst contaminant. Although phosphorus is no longer used in gasoline, it (and zinc, another low-level catalyst contaminant) was until recently widely used in engine oil antiwear additives such as zinc dithiophosphate (ZDDP). Beginning in 2004, a limit of phosphorus concentration in engine oils was adopted in the API SM and ILSAC GF-4 specifications.
Depending on the contaminant, catalyst poisoning can sometimes be reversed by running the engine under a very heavy load for an extended period of time. The increased exhaust temperature can sometimes vaporize or sublime the contaminant, removing it from the catalytic surface. However, removal of lead deposits in this manner is usually not possible because of lead's high boiling point.
Any condition that causes abnormally high levels of unburned hydrocarbons—raw or partially burnt fuel—to reach the converter will tend to significantly elevate its temperature, bringing the risk of a meltdown of the substrate and resultant catalytic deactivation and severe exhaust restriction. Usually the upstream components of the exhaust system (manifold/header assembly and associated clamps susceptible to rust/corrosion and/or fatigue e.g. the exhaust manifold splintering after repeated heat cycling), ignition system e.g. coil packs and/or primary ignition components (e.g. distributor cap, wires, ignition coil and spark plugs) and/or damaged fuel system components (fuel injectors, fuel pressure regulator, and associated sensors) - since 2006 ethanol has been used frequently with fuel blends where fuel system components which are not ethanol compatible can damage a catalytic converter - this also includes using a thicker oil viscosity not recommended by the manufacturer (especially with ZDDP content - this includes "high mileage" blends regardless if its conventional or synthetic oil), oil and/or coolant leaks (e.g. blown head gasket inclusive of engine overheating). Vehicles equipped with OBD-II diagnostic systems are designed to alert the driver to a misfire condition by means of illuminating the "check engine" light on the dashboard, or flashing it if the current misfire conditions are severe enough to potentially damage the catalytic converter.