[TheBigChill]

Originally Posted by PhaseP

Engine was running so air was flowing through it, hence not zero flow shown. The voltage being shown 0V, who knows. If you look at the first picture you have one of the O2 sensors showing zero ohm resistance. From going memory mine also shows zero ohm resistance when I check these screens, and sometime not zero ohm resistance, but I never got errors from the computer about O2 sensors.
My point these besides being in German, even in English not easy to interpret correctly.
What is apparent is your fuel trim is high, apparent from some of those % numbers displayed.
Between the two screens where it shows different air flow values, what I assume ambient temperature value is different too. Which will cause different value reported. But the values is backwards to me because hot air expanding would have less mass then cold air. I am not expert on these, and as I said it is not easy to interpret them correctly.

You're not understanding me. I know that it should flow (kg/h) while running. I'm saying that the one screenshot shows 0v at MAF. I'm not talking about Ohms of resistance.

All of these screenshots were taken at the same time, just different INPA menus.

Regarding the RPM, it's shown in the 3rd image.

Yes- fuel trims are very negative, as shown in the OBD screenshot. This is mentioned in my very first post.

[PhaseP]

I will repeat myself, but just one more time. 0 V MAF output, is it significant or just some wrong value displayed at INPA? I think it is later, because that is not the only value that is zero and doesn't make sense. I gave the example from your first screen "idestand Lambdasonde hinder Katalysator Bankd 1" is 0 Ohms, where as all the other Lambda jumbo values are not 0 Ohms.

The INPA screen are not at the same time, unless you were running 3 INPAs at the same time in your computer. So there must have been at least a few seconds when you moved between the INPA screens.
And I gave example, the temperature values changed between your screens
steuergrert Innertemperatur 50 C 1st screen
Umgebungstemperatur 42 C 2nd screen, which I believe they are the same ambient temperature sensor value. Why 8 C difference between the two?
If you waited some time between screens that can be the reason.
One other possibility other your MAF sensor pins are not contacting good, which the ambient temperature sensor is part of the MAF sensor and has pins going to the connector.

At least I can't know looking at the screen shots if the two had same RPM at the moment INPA read the values from ECU. In my experience ECU varies the idle RPM when warming up. And it also varies the idle RPM for a few seconds just after hitting and releasing the gas pedal. It takes a few seconds, may be 5 seconds with a fully warmed up engine after giving gas and engine RPM finally sitting at 650RPM. Unless you knew your RPM at the first screen you can't conclude much from the reported MAF output displayed there not matching the one on your 3rd screen.

And coming back to the 0V MAF output reported, if MAF had no output, why it reports MAF read air mass flow values in other values? If it had decided MAF is not working and going to other calculation, then it wouldn't just do it, it would in addition throw a code (may be not SES light but readable via INPA) saying MAF output is incorrect, or MAF is not connected. If you read the codes with INPA and not seeing those, it indicates MAF is not putting out 0V's.

Just my two cents...

[hassmaschine]

Ambient temp does not come from the MAF - that comes from the Kombi (TAMB). The MAF has an intake temp (TIA), they are related but functionally different and the sensors are in different locations.

That reminds me though - it turns out TAMB is also used for fuel trim adjustments, is your ambient temp working?

[PhaseP]

"steuergerät Innentemperatur" translates as "Indoor temparture" via google translate. It was reported 50Celcius in that screen, maybe if it was waiting hot under the sun with windows closed, otherwise too hot if it is what it says it is.

That reminds me though - it turns out TAMB is also used for fuel trim adjustments, is your ambient temp working?

Are you saying this because it is displayed on the INPA screen together with the trim values, or you saw in the ECU code that it is used for fuel trim?

[PhaseP]

To the OP, I found one of my screen shots when I was trying to troubleshoot my issue. My INPA is different version and has English translation.
Check the picture below, if mine is more correct as what those values are supposed to be, then your intake air temperature is very hot at 70 degree celcius. Unless you are at a very hot but a very very hot place.

And the 50 degree celcius is CPU internal temperature according to my INPA.
That is what I mean it is difficult to interpret these, somebody put the screens together with the caption texts. Not sure they are accurate.

[PhaseP]

"ansaugluft temperature" from OP's first INPA screen (Measurement Block 4) and last one (OBD SAE 1979) shows 71 and 77 Celcius.

Google translate says "ansaugluft temperature" is "inlet air temperature".

So this indicates problem with the temperature sensor on the MAF, but then I also realized around 70 degrees is a nice temperature in Fahrenheit.
So there is also possibility the version OP using may have these actually displaying in Fahrenheit, even though it says Celcius on the screen, maybe???

I don't know..... Again my point, these screens are not very easy to interpret. In any case, if it is the intake air temperature sensor, then it is either the sensor itself, or the connection that is faulty.

I don't have a saved screen shot of the "DAC" inpa screen to compare. I hadn't paid attention to those when I was troubleshooting because those are raw sensor output values and without knowing the conversion factor that needs to be used not useful.

Edit: If my memory is correct, the hidden onboard computer menu also displays intake air temperature. It could be double checked with it, if INPA is showing Fahrenheit or not.

[hassmaschine]

Originally Posted by PhaseP

"steuergerät Innentemperatur" translates as "Indoor temparture" via google translate. It was reported 50Celcius in that screen, maybe if it was waiting hot under the sun with windows closed, otherwise too hot if it is what it says it is.



Are you saying this because it is displayed on the INPA screen together with the trim values, or you saw in the ECU code that it is used for fuel trim?

Its in the code. I barely looked at the screenshots lol.

[TheBigChill]

Originally Posted by PhaseP

I will repeat myself, but just one more time. 0 V MAF output, is it significant or just some wrong value displayed at INPA? I think it is later, because that is not the only value that is zero and doesn't make sense. I gave the example from your first screen "idestand Lambdasonde hinder Katalysator Bankd 1" is 0 Ohms, where as all the other Lambda jumbo values are not 0 Ohms.

The INPA screen are not at the same time, unless you were running 3 INPAs at the same time in your computer. So there must have been at least a few seconds when you moved between the INPA screens.
And I gave example, the temperature values changed between your screens
steuergrert Innertemperatur 50 C 1st screen
Umgebungstemperatur 42 C 2nd screen, which I believe they are the same ambient temperature sensor value. Why 8 C difference between the two?
If you waited some time between screens that can be the reason.
One other possibility other your MAF sensor pins are not contacting good, which the ambient temperature sensor is part of the MAF sensor and has pins going to the connector.

At least I can't know looking at the screen shots if the two had same RPM at the moment INPA read the values from ECU. In my experience ECU varies the idle RPM when warming up. And it also varies the idle RPM for a few seconds just after hitting and releasing the gas pedal. It takes a few seconds, may be 5 seconds with a fully warmed up engine after giving gas and engine RPM finally sitting at 650RPM. Unless you knew your RPM at the first screen you can't conclude much from the reported MAF output displayed there not matching the one on your 3rd screen.

And coming back to the 0V MAF output reported, if MAF had no output, why it reports MAF read air mass flow values in other values? If it had decided MAF is not working and going to other calculation, then it wouldn't just do it, it would in addition throw a code (may be not SES light but readable via INPA) saying MAF output is incorrect, or MAF is not connected. If you read the codes with INPA and not seeing those, it indicates MAF is not putting out 0V's.

Just my two cents...

1) I don't know if it's significant or not. I'm merely noting that it's odd for a MAF to have 0v output, even at idle. It's possible that that my car doesn't report this parameter, but again, that's odd too, as all others do.

Additionally, my question wasn't related to just MAF voltage; it was also asking "Why do I have two significantly different kg/h results depending on which screen I view. **All screenshots were taken from a car at warm idle, with no changes to environmental conditions between each screenshot. They were all taken within 60 seconds of each other. What the means is that there was NOT actually a 8*c temp swing between screenshots.


2) Ambient temp is not integrated into the MAF. You are thinking of Intake Air Temperature.

3) RPM's were stable in each instance that a screenshot was taken.

4) I understand that a faulty MAF would throw a code if it was so broken that it was reporting 0v. I'm mostly asking someone else to confirm what their MAF reading is on that same screen (also 0v??).

[TheBigChill]

Originally Posted by hassmaschine

Ambient temp does not come from the MAF - that comes from the Kombi (TAMB). The MAF has an intake temp (TIA), they are related but functionally different and the sensors are in different locations.

That reminds me though - it turns out TAMB is also used for fuel trim adjustments, is your ambient temp working?

The temperature sensor that is attached to the windshield cowl was disconnected while these screenshots took place, because I had the cowl off of the car for troubleshooting.

The sensor seems to be fairly accurate though, as I hooked it up today when assembling the cowl.

I'm going to go out with INPA, and disconnect that same sensor and see which parameters go high. I'm also going to use the E90 menu (MSV80 ECU) instead of the one for the 1er, as the E90 one is more translated to English.

PhaseP: Did you happen to notice the differences in the Lambda (before and after cat) Ohms, shown in "Measurement 6" screenshot? Mine are all at 256 Ohms (except for one is 0 ohms), while yours are much much higher. That seems odd, too.

[PhaseP]

The temperature sensor that is attached to the windshield cowl was disconnected while these screenshots took place, because I had the cowl off of the car for troubleshooting.

There is no temperature sensor attached to windshield cowl. That is an "air quality sensor", which I think is just a humidity sensor. According to realoem only comes with automatic air condition cars:

https://www.ecstuning.com/b-genuine-...l/64119240180/

This below is the outside temperature sensor, and where it is exactly it is is a mystery, could be behind the bumper somewhere, don't know:

http://www.realoem.com/bmw/enUS/show...68#65816905133

About the 02 sensor resistance, I had already answered what you are asking
in a few posts before:

"From going memory mine also shows zero ohm resistance when I check these screens, and sometime not zero ohm resistance, but I never got errors from the computer about O2 sensors."

[TheBigChill]

Originally Posted by PhaseP

There is no temperature sensor attached to windshield cowl. That is an "air quality sensor", which I think is just a humidity sensor. According to realoem only comes with automatic air condition cars:

https://www.ecstuning.com/b-genuine-...l/64119240180/

This below is the outside temperature sensor, and where it is exactly it is is a mystery, could be behind the bumper somewhere, don't know:

http://www.realoem.com/bmw/enUS/show...68#65816905133

About the 02 sensor resistance, I had already answered what you are asking
in a few posts before:

"From going memory mine also shows zero ohm resistance when I check these screens, and sometime not zero ohm resistance, but I never got errors from the computer about O2 sensors."

Ah, that makes sense. I was wondering why they would put it in a spot that will always be warm...

Anyhow, I let the car warm up last night, and then looked at INPA again. Instead of Intake Air Temp being 72*c, it was 39*c. This makes much more sense. I'm not sure if there's an intermittent problem with the IAT sensor in the MAF or what...

Typically, when an IAT sensor sees a higher temp, the result is actually less fuel because the ECU assumes that higher temperature air is less dense. Lower air density requires less fuel. This is the opposite of the fuel trim readings I currently have. Regardless, I'm going to swap MAF and connector once my DryFlow filter arrives.

[Binaryguy]

TheBigChill Have you got further update on the issue you were having? I think we are on the same boat and i'm still doing diagnosis. I've swap the fuel injector thinking might be a leaking one. Somehow i'm getting -10% LTFT on bank 1 and 0% on bank 2. I'm thinking it might be my MAF too.

[TheBigChill]

Originally Posted by Binaryguy

TheBigChill Have you got further update on the issue you were having? I think we are on the same boat and i'm still doing diagnosis. I've swap the fuel injector thinking might be a leaking one. Somehow i'm getting -10% LTFT on bank 1 and 0% on bank 2. I'm thinking it might be my MAF too.

I swapped my MAF with a new unit and the SES never came back.

Given that you have a pretty different Fuel Trim for each bank, I'd start looking at things that can affect only a single bank; such as injectors, like you said. Before buying new parts, you could always try swapping fuel injectors from Bank 1 to Bank 2, and see if the issue follows the injectors. Also, I'd consider a primary O2 sensor.

[Binaryguy]

Originally Posted by TheBigChill

I swapped my MAF with a new unit and the SES never came back.

Given that you have a pretty different Fuel Trim for each bank, I'd start looking at things that can affect only a single bank; such as injectors, like you said. Before buying new parts, you could always try swapping fuel injectors from Bank 1 to Bank 2, and see if the issue follows the injectors. Also, I'd consider a primary O2 sensor.

I doubt it is the o2 sensor. Both are idling @ the same voltage (~0.7v).

Throw in the new MAF and no improvement. Will swap injector and see how we go.

[Binaryguy]

See below parameter

[TheBigChill]

Originally Posted by Binaryguy

See below parameter

If you have one or more cylinders that are running too rich on that particular Bank, you could pull the plugs and inspect them too. That could help you narrow down which of the 3 cylinders is running rich, and as a result tell you which injectors to give attention to.

Just for the hell of it, I would smoke test the car, too. Things like cracked valve covers and malfunctioning PCV systems can have weird effects like this.

I made a simple smoke tester using a plumbing pipe cap, rubber adapter, 1/4" hose barb, vac line, and...cigar. You just need to safely hold open the throttle body plate so you can pass smoke into the head. I have photos if it helps.

[hassmaschine]

That's awesome. Do you get to smoke the cigar?

[Xencer]

You could also check the coolant temp sensor value, if it is open it should read -40* F which would cause an increase in fuel injection

[TheBigChill]

Originally Posted by hassmaschine

That's awesome. Do you get to smoke the cigar?

I did, but you wouldn't want to. It was a "corner store special", and if I recall correctly, it was Alize' flavored.... Not quite a Cuban.

They tricky part is holding the throttle plate open without dropping whatever you use to hold it into the intake manifold. Watch that.