Intake Air Quantity

[Majkl]

Hi,
I have Fiat Marea 1.9 JTD 110, ECU Bosch EDC15C7. I methings that unit read value "Intake Air Quantity" is in kg/hour but value "Desired Intake Air Quantity" is in mg/i.
For example: engine idle - Intake A.Q. is c. 45 and Desired Intake A. Q. is 300.
Engine is going good, debimeter is new, errors ECU unlisted.
This topis solved forum at program UnidiagKWP2000.
http://www.forum.alfaholicy.org/147_156 ... te-17.html

"Converting mg/stroke to kg/hour

When reading data from the ECU, the mass air flow is not reported in kg per hour but in mg per stroke. Converting one value to the other is quite simple:

At 900 RPM a 4 cilinder 4 stroke engine makes 900 RPM * 2 strokes/revolution * 60 minutes in one hour = 108,000 strokes. So if the ECU reads 480 mg/stroke at idle, it equals to 108,000 * 480e-6 = 52 kg/hour air flow.

480 mg/stroke is the value you should read with a 1.9L engine during idle when the EGR is closed. One full cilinder filling is 0.48 liter. Air is about 1290 mg per liter. So one could calculate 0.48 * 1290 = 619 mg/stroke. However, the cilinder is not fully filled as it has to suck in the air in a limited amount of time. Therefore the value is a little lower. (If the turbo would be really working at idle, the air flow could be higher than 619 mg/stroke.)".

Is right my idea?.......

Majkl

[tomsa]

YES, you are right.

tomsa

[heinjan]

Hi,

i have a alfa 156 1.9JTD 2001 model, exact same ECU, very likely exact same engine as well. EcuScan reports a desired intake of 285-300 mg/stroke but my LMM reports more, usually about 480 at idle (850 rpm).
Now i am a bit confused, as per your calculation, the 480 mg/stroke is far more likely to be correct than the desired indication of 285-300 mg/stroke.

I also understood that defective LMM's (air mass meter) usually report too low values, instead of too much(mine usually report about 2x the parameter 'desired air intake').
so let's assume the LMM is OK. That would mean that the ECU calculates
the amount of air intake faulty. The only thing i can think of, is the lambda sensor reporting a flawed value, but i was unable to find that parameter in the software. Not
sure if it is in there. Do you have any clue how much lambda sensors the 1.9 JTD has ? and if they are in the parameters, what parameter represents which lambda sensor?

The EGR got stuck (stored error in the ECU) , i thought that would be the issue, but after intensely cleaning the EGR and manually testing it, that didn't change any reading. (btw the actuator test
on the ECUSCAN failed for the EGR, but when running the engine, it does report the valve open when running at non-idle)

Hope anyone has an idea about this, as i cannot verify the fuel-air mixture if i cannot find the lambda data...

[alfa156sarajevo]

As far as i know JTD engines do not have lambda sensors!?!
I have seen so many Alfas JTD from the bottom but haven't seen any lambda sensors on the exhaust system!!!

[yani]

From the info that I have from other EDC15 JTD engines:
- The intake air mass is ~420 mg/i at idle when the EGR is closed
- The inteake air mass is ~300 mg/i at idle when the EGR is open (this is the normal condition)

[Gianremo]

From the info that I have from other EDC15 JTD engines:
- The intake air mass is ~420 mg/i at idle when the EGR is closed
- The inteake air mass is ~300 mg/i at idle when the EGR is open (this is the normal condition)

Sorry Yani, do you know the same parameters for Grande Punto 6F3EOBD MJT engines?

Thanks