With the key in position 2 and the engine off, can you hear the ICV humming? It may need cleaning or replacement.

I suspect the Cat's are struggling with the high gas flows at high rev's.

This leaves the MAF. Have you introduced a vacuum leak? Has cleaning the MAF broken it?

 

With the key in position 2 and the engine off, can you hear the ICV humming? It may need cleaning or replacement.

I suspect the Cat's are struggling with the high gas flows at high rev's.

This leaves the MAF. Have you introduced a vacuum leak? Has cleaning the MAF broken it?

Yes, clearly hear the ICV.

Pulled the MAF to clean again and put some dielectric grease on the some harness connectors. initial start up is not as stable as I'd like to hear (maybe IAC) and see with fuel trims, but once warmed up my idle LTFT are pretty solid at 7.0% and STFT are about 0%. holds steady with an increase in revs. For now i think I'm comfortable with the MAF until I check for vac leaks. MAF flow rate is 3.7g/s and rock solid. Most of the potential areas for leaks have been replaced when I had the intake off or the starter replacement, but maybe things like valve cover gasket have leaks that show themselves when cold and not as apparent when hot.

Going to smoke test and move on from there.

Still interested in seeing your absolute throttle position numbers through the MAF test execution. The calculated load % is still the same and still wondering if the TPS is a problem.

 

Add the new PID's to your normal OBD Fusion log. That way I have sort of "frame of reference". I'm happy to look at the results. I'm curious too about the calculated load% and absolute throttle position% issues.

 

I added them, but after changing the wide bands I didn't notice any changes other than more stability in output signal. i then proceeded to take off the MAF and clean it (not usually a big proponent of cleaning with MAF solvent) and wouldn't you know it all changed. As a matter of fact it almost went the opposite and was at like +14% LTFT (while driving highway) in each bank. Did notice though that at idle it is now around +4% in each bank. No more pending codes for rich conditions in 1st and 2nd bank. This behavior is making me think more and more that the MAF might be the issue, but I think I'm going to swap out the post-cat O2s because the signal seems to jump too much and I'm wondering if they are sending improper signals to the DME for A/F calcs.

I did perform the MAF test again and the link to the data is here CSVLog_20210320_225414 (MAS test - post t-stat, post MAF cleaning, post wide band replacement).csv

- Calculated load still indicates that wonky behavior of 0% on cruise with no throttle. At idle it's like 4%.

- Not sure why my throttle position just does not really change when increasing RPMs slowly through 2k (starts and stays at 10.6%), but does change when more rapid depression of gas pedal occurs. I know that's a factor in the DME using reference maps, but still seems off.

-observed again that slowly increasing RPMs up to about 1200k it is virtually impossible to slowly and linearly climb up in revs. The rpms will increase and then slowly drop down a 100 or so rpms. No way I can climb to say 900 rpms and hold steady without a slight drop. In my G this is not an issue at all and doing the test is far easier. Going to try it in my GF 2018 X3 just to see the behavior. Not sure if this is normal, indicative of a foot pedal issue or a TPS issue.

-Started to manually monitor my gas mileage to see what I am getting in relation to what is expected on avg from this car. Going to check the pressure in the fuel rail and make sure the FPR is working properly.

 

NZ00Z3...I've noticed what seems like a little wonky behavior with my throttle position % in OBD Fusion. Since this car doesn't have a MAP sensor i've decided to log the following variables and run the MAF test we ran:

Intake manifold absolute pressure (under calculated PIDs)
MAF rate
Absolute throttle position sensor
Calculated load value

I'm starting to wonder if the TPS is sending out improper values or if the throttle body itself is problematic. I thought when I had to replace the starter I had to take off the TB. If so I'm sure I would have cleaned it, but don't recall since it was a few years ago.

Would you be willing to run an identical MAF test and log the variables that I have identified above? If there is anything else you can think of just let me know. Running this tonight after I change out the wide bands.

Thanks,
Jon

 

Remember how your absolute throttle position always looks off. At Idle its running around 10%. Throttle control is how the DME overcomes the impacts of air density. Air Temp, pressure and elevation all impact air density and the amount of oxygen in the Air. The Engine uses a Mass Air Flow sensor to get a standard amount of oxygen measurement. In hot temps, the throttle is open more to get that amount of oxygen than on colder days.

If the Table in the DME that calculates load uses the throttle position to compensate for air density, then your problematic absolute throttle position value will have a direct impact.

 

Good point. Now this is going to f'ing bug me and I already see myself going down a rabbit hole Hopefully this is one of the fun holes that ends up with big smiles and not 5 figures in the pockets!

Still waiting to hear back from the techs, but I will change the widebands and do my other maintenance stuff I had lined up. These ECU/DME problems have always ended up becoming like second jobs. I will probably start out by seeing if someone is around that can swap their MAF so i can see if that changes the behavior.

Will keep you updated.

 

With regards to the load. You are getting expected values at idle, when coasting and at WOT. The drop from idle to 2-5% at park and slowly raising the rev's is a curiosity. I'm interested to hear what you find out.

Yes -7% is a little rich. Fit the new wide band pre-cat O2's and see what difference it makes.

I'm about to go down and do a cold start log on the M52TUB20 with TestO to get sub-second snapshot data for the narrow band pre-Cat O2's. Using 5 second data to diagnose something that cycles 8 to 10 times a second, does not add up to me. TestO may be too slow too, but its the best I have at the moment. The LTFT's for this car are in the -6.5% range.

 

Tuner is bringing up the issue with the techs and see if they think of anything. Probably won't get an answer until tomorrow.

On a side note I was driving my G today and monitoring calculated load. Couldn't get mine lower than 13% on coasting decel and at idle was like 14%. No way could I get below 13% in any scenario.

Would you happen to know what monitoring variables are used to calculate load % on OBD Fusion? I've seen the theoretical calculation online, but I'm wondering is the app uses other PIDs to calculate for the PID. If that can be determined then maybe I can independently monitor them and see which value is pulling the % so low.

 

While search for negative fuel trim problems, I came across this thread Another failed story about troubleshooting a cold start...

Edit. The above link is useful for narrow band pre-cat O2's. The OP has wide band O2's, so this post has been edited back.

 

While search for negative fuel trim problems, I came across this thread Another failed story about troubleshooting a cold start...

Edit. The above link is useful for narrow band pre-cat O2's. The OP has wide band O2's, so this post has been edited back.

NZ00Z3...FYI, I was driving the car this afternoon and at idle calculated load % was around 13% and changed with throttle manipulation. I could consistently make it hit 0% when coasting at speed and no depression of pedal. Inversely I could make it hit 100% with WOT depression. At idle and Park I slowly ramped up revs at a light and load % was pretty consistently around 2%.

Reached out to the programmers of the DME currently in the car (stock program) to see if they had seen any such behavior in their experiences.

With regards to LTFT, car is still high'ish at like -7%+,but saw it jump to-10% during some driving. I have a set of new Bosch widebands that were just delivered so I'm thinking of just changing them out even though the old ones are still operating. I assume maybe some degradation in response (like the posts you initially put up) might make a difference and the car does have over 100k miles on it now.

Thoughts?

 

..

 

NZ00Z3,

About the negative fuel trims, I recall jfoj making a comment a few years ago that these were more common for euro cars but not for North American tuned cars. I don't recall the particulars of why that might be the case. Don't know if that applies to you in New Zealand though, but you reminded me of that.

 

It could be. Two are Euro spec and one is a Japanese import, so don't know what spec that is. The 2 M52TUB's bot have M54B25 inlet manifolds fitted. I remember reading something a long time ago that this will cause negative fuel trims. Don't know if its correct or not?

 

Here is the last MAS log after the t-stat replacement. Upper range got quick, but hopefully enough data points to see what is needed. CSVLog_20210315_195030 (MAS airflow test post t-stat replacement).csv

 

LOL, I had the same problem with lost logs in OBD Fusion yesterday.

Tip, Go to Settings, Vehicle Editor. Top right is a "Menu" button. Click on it and it will let you "Select Vehicle". You'll find the other car in there and the associated logs.

Great to hear that the thermostat has had a good effect on running temps.

We talk about the LTFT spec being +/-4% for a good vehicle and if its more than +/-8% then you have a problem. I agree with on the cars having negative fuel trims when in good condition. I have 3 BMW's. Two with M52TUBXX engines and a very low km's M54B30. All run negative long term fuel trims in the -4% to -7% range. My crusade since the middle of January has been to find out why. After extensive testing, I can't find anything wrong, so they must be all good.

 

F@$#?ing shit, I should have looked in this thread before I emailed tech support. They told me exactly what you did. LOL

Yeah. I learned with my Z years back from a guy who was working on maps for upgrade EPROMS that car manufacturers always error to rich for obvious engine durability reasons. Also why you can always squeeze extra juice with advancing the timing and tweaking the A/F/. It's I've always seen since then, but I'm no professional and only an enthusiast.

Thanks for the feedback

 

Question NZ00Z3 (or anyone)...I use OBD fusion on the E46, but also on my G37. I ran the MAS test again after I changed the T-stat. I then switched it to my G and ran it on there a few times. Now when I go to look for the log to send you it only shows me a history of logs for my G and not the E46.

Is there a way to see logs for both cars in OBD Fusion? If not I will perform again later today after I get back home.

Also, temp is rock solid with the new t-stat. Idling is around 92C and around town is 94C. After driving for a while and idling in garage it was 95C.

Long fuel trim was pretty solid around -7% never moving more than +/- .5%. From my shade tree mechanic experience it still seems high. I expect it to error on the side of caution with the OEM being slightly rich, but I think that % is too high, right? For loose comparisons my G runs about -.3% long fuel trims.

 

In your logs, the Absolute Throttle Position (%) numbers hardly move. They are stuck at 10.58823 for far too much of the time. Is your idle control valve stuck?

Quick test. Can do it with the thermostat out as you are not starting the engine.

Key in position 2, Can your hear a humming under the inlet manifold? You should be able to.

Take the idle control valve out, a couple of screws then a twist tug to get it out of the rubber grommet. It should rattle freely when you shake it. Clean it with carb cleaner or brake cleaner. Lots of black carbon crap will come out.

Is your car a manual or automatic transmission?

 

In your logs, the Absolute Throttle Position (%) numbers hardly move. They are stuck at 10.58823 for far too much of the time.

Unfortunately, I have noticed the same thing in many of my data logs ... and I'm not sure if it's my old phone that can't keep up, if the app itself can't process that data pid correctly or what the issue is. Just something to keep in mind.

 

It's better being done after the thermostat. Removes one possible cause of the problem.

You are doing well. Keep up the good work.

 

Thanks for running the data points Murray. I did start to take some things apart today since I should have my fan removal tool tomorrow and will throw the t-stat in. Outside of obvious better fuel combustion (if the t-stat really does fix the temp issue) is there any issue with me doing this test after the t-stat is replaced? If so I will throw it back together and perform before I swap it.

 

..

 

Huge props to @NZ00Z3 and @LeverThis for digging in and helping OP troubleshoot this.
You guys are taking diagnosing these issues to a whole new level. Amazing!

 

Kudos also from me too!

Forums like this (repository for technical information and guidance) are critical for enthusiasts who want to do their own work. I embarked on my own mechanical path long ago coming to the realization that NO ONE will put the time and care into you car like you will. Especially as you climb the performance ladder.

As I become more familiar with this car and platform in general, hopefully I will be able to reciprocate and contribute to the knowledge base around here.

 

No need to re-do the OBD Fusion logs. I have loaded all the data into my spreadsheet.

My BMW's run about 96 C on the open road.

 

Here is the MAF data you requested. Disclaimer: it was extremely difficult to linearly ramp up rpm's at such a slow increment. I had to use my hand and I believe it spanned only over 3 min. Hopefully this is good enough. If not i will try again.

Dropbox

www.dropbox.com

 

I'd also like to add some further info:

Replacing my thermostat today, but will run the MAF test prior and after so as to minimize the amount of variables when assessing.

Last night driving into the city my temps were anywhere from 75C to 90C. On the highway it was usually between 75-85 and when in the city it was around upper 80's and 90.

 

I'd also like to add some further info:

Replacing my thermostat today, but will run the MAF test prior and after so as to minimize the amount of variables when assessing.

Last night driving into the city my temps were anywhere from 75C to 90C. On the highway it was usually between 75-85 and when in the city it was around upper 80's and 90.

That sounds like a soft failing thermostat (temp drops on the highway), hopefully the new one does better. One point of order, the temp sensor in the lower rad hose is the radiator outlet temp sensor/switch, which the dme uses to run the electric radiator fan. The engine coolant temp sensor that the tstat is controlled off of (and is the reading you see in obdfusion & powers the temp gauge on the instrument cluster) is at the back of the head near the firewall, under the intake manifold at cylinder 6.

As for inpa cable look for one on amazon or ebay that has the little switch for connecting & disconnecting pins 7 & 8.

How to Install BMW Standard Tools

This thread describes how I install and configure BMW Standard Tools, the suite of BMW software that includes INPA, NCS Expert, WinKFP, Tool32. I have my own custom way of doing this that is the shortest and simplest steps I could figure out. This set up is for E46 only. What is needed...

www.e46fanatics.com

 

Hi

Welcome to the forum. Well done on getting set up with OBD Fusion and running the fault reports and 3 logs. Most people don't get this far in there first 3 posts, so my hat is off to you.

Tips for OBD Fusion:

• You have used 100 ms snapshots. This is way too fast. Look at your data and you'll see that it changes around every 4 seconds (40 odd rows of the same data). Set your snapshot rate to 5 seconds. Better data and saves us from wading through 1,000's of lines of repeat data.
• The car has wide band O2 pre-cat sensors. Thank you for seeing this and logging the Lambda data. It would be helpful to also log the pre-cat O2 values in milli Amps (mA).

I've been through your logs. There are some crazy numbers in there. Did a comparison with my M54B30 doing the same logs.

• Your engine temp is low. The new Thermostat will likely take care of that. A low engine temp will give you rich fuel trims, but I think there is something else going on with your car.
• Your hot idle MAF reading is high, this could be due to the low engine temp?. Lambda are about right, they are cycling between rich and lean, but you have crazy -25% rich total bank fuel trims.
• In the highway log, It starts out with the calculated engine load at about 3 times high, the MAF flow is about 3 times high and the Lambda are 2 times high. It then settles down with the MAF and Calculated load about right. The Lambda's cycle rich to lean as they should the the total fuel trims per bank max out super rich, as in -30%

There are 2 things that come to mind for your car's rich condition:
1) You have an over reporting MAF. The start of your highway log with the 3 x MAF value has me worried. We had better do a quick MAF test. See below for instructions.
2) You have blocked or partially blocked cats. This is less likely as your post-cat numbers are about right. The quick MAF test will help here too.

Quick MAF Test
As you already have OBD Fusion set up with all the right PID's, set the snapshot time to 5 seconds.

With a hot engine at idle and car parked up. Start the logger. Slowly raise the rev's. I mean slowly. All the way to 4,000 rpm. Stop the log. As a guide, I take about 3 minutes to do this test.

Load the log in Dropbox and I'll run the results through my spreadsheet that is set up for MAF testing.

Regards

Murray

 

Thanks for the quick response Murray

Sorry about the data timing as I thought I switched it to 1 sec, but I will check and change to 5 s. I will also add the other pre-cat o2 pid, but can you confirm the exact PID I should be checking off in OBD Fusion as there are many O2 sensor PIDs and I don't have the knowledge base to discern what's appropriate? Still learning the obd fusion interface.

Would you prefer I run the logging tests again with the changed data timing and o2 inputs?

Also, not directly related, but do you know of a good US cable source for INPA and BMW Scanner? I'd like to be prepared seeing as I could be dealing with one of those issues that take intensive investigating and trial and error.

Fyi, when we got this car a few years ago the DME failed and I had to get another one reflashed from a reputable place in Canada. Not saying that's the issue but just making it known the brain was replaced. Also, no rich exhaust showing even with such absurd rich Conditions.