Ideas and suggestions to my X5 issue
 

I was cruising home with family from NC after the weekend trip. The SAV suddenly downshifted and lost power. I also heard some poping sound underneath. I thought it was transmission related. I pulled over, walked out and check. When I looked under, the cats were glowing red at the rear section. The X5 could barely keep the idle. I shut it off, called a relative to pick us up and a tow truck to get the X5 home.

This is my initial diagnostic: excessive un-burn fuel get burn in the cat. It might have melted the inside and block exhaust flow. No CEL and no symptom before it happend.

Transportador suggests that I also look for blockage or damage after cats section, that would cause exhaust flow constriction.

What do you think?

I'll find out the cause first and fix it before having the cats replaced.

Sounds plausible. As for the cause... stuck injector or failed FPR? Sorry can't offer anything other than that as I've don't recall seeing a vehicle come in with those symptoms at the shop.

Why u replace cat? Here we usually take them out...and sound is great...plus u get hp :)

In the US it a Federal offense to remove a catalytic converter, and no shop will ever do it. The car will fail every inspection, and even if you bring the car for tire change, and the mechanic will see no cats, he must report it. with annual State inspections, and emissions, you are bound to present your car to a stranger at least once a year...

I am surprised that in Latvia, which is part of EU, they will allow uncontrolled removal of the cats, unless leaded fuel is common there (which i doubt).

TMV, in my line of work, we would usually check for a "potato" in the exhaust - some smart a$$hole shoving a blocking device down the exhaust to cause that specific effect that you experienced and stop the car.

How many miles do you have on your x5?

^Almost 122K miles

Did the catalyst material get knocked loose and dislodged further down the exhaust section somewhere?

Sorry to hear about your SAV.

Are both cats shot?

O2 sensors....are they intact?

Maybe you have an injector thats dumping too much fuel thus causing the cat to get excessively hot and glow. Its highly unlikely that both cats would be clogged at the same time. If both are glowing then like I said you could have some failed injectors. In any case you got to hookup the scanner and see what codes come to life and begin the diagnosis from there.

No code from OBDII reader, except a pending "P0111" which is Intake Air Temperature code, that I think is unrelated.
INPA stop working after I select E53 -> Engine -> N62. So I have no code from INPA
GT1/DIS shows no code related to engine, only pending/stored codes from PDC, and LCM.

I'm at a dead-end now. I did start it this morning. It was struggling the first try but started on 2nd try and every time after that. It drives around the block just fine.

You can take a compression gauge and remove the pre-cat 02 sensor and screw in the gauge and see what type of back pressure therre is.

Here's a video on on testing the cat with a pressure gauge, go to 4:00 into the video.

https://www.youtube.com/watch?v=9TlygJMxTps

You was probably burning rich for the CAT to overheat and glow red. Take a look at the long term term fuel trim and the short term fuel trim. Could be a bad MAF, check what the airflow through the maf is. Flow should be in Grams per second.

Very helpful upallnight. Thank you. I'll check them and report back.

Have you tried giving it a solid rip. Make it move, get the flow going. Maybe someone did stuff some shit in your exhaust.

It seems to run just fine now. I gave it a few good revs.
http://vid300.photobucket.com/albums...pslzixvsok.mp4

MAF seems to have no affect on engine. It must be bad. Engine idle perfectly 695-715 rpm with or without the MAF plugged in.

upallnight, I read the Mass air flow with GT1/DIS. It's 27.2 kg/h or 7.556 g/sec

http://i300.photobucket.com/albums/n...psduperjzk.jpghttp://i300.photobucket.com/albums/n...pseswfxn8h.jpg

Well a shot maf will mess with your fuel. Which will mess with the cats.

How is the fuel mileage by the way?

And I still suggest you get it moving, and give it a few pulls to red line. Get it warmed up and see what happens after to those cats.

I also had a similar problem with my Lexus GS430 when I had a piggy back ECU for my intake. My maf died, but no check engine. The software that was in that piggy back ECU was hiding and over riding the maf error. I had a bitch of a time figuring it out. Same issue like you. Cats got stupid hot. Once I removed the ECU and went to factory intake, the maf code came up. Maybe the dinan stuff is doing something similar?

Was the engine in "Closed Loop" when you took this snap shot? By closed loop I mean was the engine warm up?

http://i300.photobucket.com/albums/n...pseswfxn8h.jpg

It appears that the engine is in "Open Loop", so the 02 sensors are not controlling the mixture, in open loop a default set of parameters are controlling the mixture.

I would hook up a scanner and view live stream data for the 02 sensors. You should be able to see voltages that the sensors are generating as inputs to the DME.


OXYGEN SENSOR DIAGNOSIS

O2 sensors are amazingly rugged considering the operating environment they live in. But O2 sensors do wear out and eventually have to be replaced.

The performance of the O2 sensor tends to diminish with age as contaminants accumulate on the sensor tip and gradually reduce its ability to produce voltage. This kind of deterioration can be caused by a variety of substances that find their way into the exhaust such as lead, silicone, sulfur, oil ash and even some fuel additives. The sensor can also be damaged by environmental factors such as water, splash from road salt, oil and dirt.

As the sensor ages and becomes sluggish, the time it takes to react to changes in the air/fuel mixture slows down which causes emissions to go up. This happens because the flip-flopping of the fuel mixture is slowed down which reduces converter efficiency. The effect is more noticeable on engines with multiport fuel injection (MFI) than electronic carburetion or throttle body injection because the fuel ratio changes much more rapidly on MFI applications.

If the sensor dies altogether, the result can be a fixed, rich fuel mixture. Default on most fuel injected applications is mid-range after three minutes. This causes a big jump in fuel consumption as well as emissions. And if the converter overheats because of the rich mixture, it may suffer damage.

Here is a screen shot from a video last night. Both pre-cat O2 sensor heater is jumping back and forth from "not active" to "Active". The pre-cat O2 sensor readiness is ready.

http://i300.photobucket.com/albums/n...psdxbx3jdg.png

Since the 02 sensor appears to be working I would look at the long term and short term fuel trim.

Did I look at the right place?
http://i300.photobucket.com/albums/n...pssxobr1lo.jpg

I normally don't use any of the BMW specific software to see live data. Instead I use an app called Torque with either my Android tablets or Android phones.

I keep an OBD II bluetooth reader in the car at all time and if I want to check something out, I always have my phone on hand.

IAT has a big impact on the MAF accuracy and the engine fuel control.

Some engines have a 3 wire MAF with the IAT in the intake between #3 & #4 intake runner. Not sure if the E53 was like some of the other cars with later versions having a 5 wire MAF with the IAT as part of the MAF.

MAF reading also sounds very high, over reporting, which will cause more fuel to be added to the engine. Most 3.0l will have a MAF reading of 3.6 g/s in park/neutral @ 700 RPM.

If your MAF reading is really in the 7+ g/s range, you have a problem, but also make sure the IAT problem is not impacting the MAF reading/conversion. IAT readings also impact ignition timing as well. I would bet your LTFT are in the negative range, which they should not be.

Suggest you consider the OBDFusion App, $1 cheaper than Torque and not at buggy. OBDFusion along with the VeePeak BT interface from Amazon is less than $20. OBDFusion is also available for iProducts, the App and interface for an iProduct platform is typically under $30. iProducts typically require a Wifi interface rather than a BT interface.

You can also use the App to Log the O2 sensors and this will show you what kind of health the catalytic converters are in, you may have already done damage and caused them to melt down. Typically you need an exhaust back pressure tester, although a compression tester may work, it usually does not do a very good job at low pressure reading. You can get a proper tester for around $37 - Amazon.com: Tool Aid 33600 Exhaust Back Pressure Tester: Home Improvement

There's a free version for Torque, but I found the app to be very helpful that I brought the Pro Version of Torque to support the developer. I have used it on all of my cars with OBD II and never had a problem with it or found it to be buggy. You can check out the reviews by other users before downloading the app.

I know Torque far too well, I have it because it was around before OBDFusion came out. I have found that Torque has problems Logging O2 sensors and it DOES NOT properly support Wideband O2 sensors. I have attempted many times to get these issues corrected and the Torque developer is basically NON RESPONSIVE. The developer does not communicate directly with the end user, they only work via the Torque Forums.

I have been using and working with the developer of OBDFusion on many of his products. I have had many exchanges with the OBDFusion developer on bugs, issues and enhancements and OCTech has been very responsive. OBDFusion is also one of the few lower cost, higher performing Apps that has BOTH an Android and iProduct products.

One of the few Apps that will actually Log Fuel System Status and properly supports Wideband O2 sensors.

https://www.obdsoftware.net/

This is not my first rodeo with OBDII tools, I have more money wrapped up in OBDII tools and manufacturer specific software than many people have in their vehicles. OBDFusion is my first go too App/Tool for driveability and Logging.

While many people have Torque Pro and use it, I do not promote or regularly use it due to the bugs and missing features.

I do however promote products that I use and that the vendors properly support. I am in in regular contact with many OBDII tool (consumer and Pro level) and software providers and point out bugs and requesting features and changes to their product lines. I tend to support suppliers that LISTEN to their end users and fix problems with their products.