530i significant loss of power, Cylinder 1 burning fail

[nasco]

Hi again, unfortunately, I'm back this time with an Issue on my 530iA. My brother the main driver, has noticed over the last couple of days that the car has slowly but surely been losing power at a rather closer than preferred to an exponential rate. He reported about three weeks ago that the car if it sat in traffic, would smell like it had an exhaust leak which you can smell within the cabin. Fuel and such that you would expect from the tip. He then noticed an abrupt loss in fuel economy to a mere 18mpg, which for Highway Commuting is actually quite abysmal considering how well the car was doing 2~ months ago.
Today my brother experienced an almost complete cutout, upon applying full throttle to the pedal, the RPM stuck where it was and then completely dropped off. As the car gets warmer, it has less and less power. In order for the Car to be even somewhat driveable, you need to use 25% throttle at a max. There is certainly a very rich smell coming from the Exhaust out the back, and I did some research and saw that typically the Source CAN BE due to 1 of 4 issues. The First being that the MAF is completely gone, the second being that there is a huge Vaccum Leak between the Intake and the Throttle Body, and the third but yet unlikely option that both of the O2 Sensors Kicked the Bucket, or there are issues with Fuel Pressure. However no one ever followed up, so the answer remains in the air. Scanned the vehicle today using INPA, the ECU read that there is a Burning Fail on Cylinder 1, and that the o2 Sensors were reading Rich on both banks. There were codes to go with that but no SES light.

I would attach the screenshots of the INPA screens, but it's as simple as the Fuel trims read 0's, the lambdaintegrator figures read in the 14's. The o2 sensors read anywhere from .58v to .7v on both banks before and after the cats. The issue goes away very temporarily if you restart the car, and the Dash Displays no Engine Fail Safe mode of any sort. The TV Probe heating before and after the CAT's read at 99.31%. I've read that this means that they are essentially maxed out and they are trying to adjust the fuel trims and they're still failing to do so. The Rough Screen shows that when the issue shows up, Cylinder 1 is showing 8.1%, and its way in the red, Cylinder 3, appears to be at 3.6%, Cylinder 6 is a little high at 2.3, and everything else is sub 1%. I replaced the Spark Plug on Cylinder 1, and swapped the Coils between Cylinder 1 and 2. The Code hasn't moved. Unplugging the MAF or switching it out with the one in the truck (It might be faulty, I'm not sure it came with the car) made no difference at all. I sprayed Carb Cleaner throughout the intake side of the Engine Bay. I'm stuck as to what the issue actually could be, I don't want to throw money at it like a grenade and hope for the best. My next step is to take apart the Intakes and see if I'm missing any tears or cracks in the Boot.

What Else Should I check? What data do you need from me to better Diagnose the issue? Your responses are greatly appreciated, thank you in advance.

[Poolman]

Sounds to me like the cats are backing up. No where for the exhaust to go. Don't under stand why you don't have any codes though.

[djb2]

The e39 cats are large and close to the engine. Unless the engine has been burning lots of oil for a long time they are unlikely to clog.

I would start by taking off the intake boots back to the throttle body and see if there is something obvious. While you are there, unscrew the ICV bracket, take off the ICV, give it a shot of cleaning spray, and re-seat it. I've seen a vacuum leak where a hack mechanic obviously just bent the bracket to pull off the ICV. It must have initially sealed, but the twisted bracket eventually opened a gap.

If there isn't anything obvious, the next step is a leak-down test. If you have zero compression on a cylinder, try a solvent soak to dissolve carbon that may be holding the valve open. If that's the problem, hopefully you caught it before the valve burnt.

[Aussie528iT]

I recently had a somewhat similar issue regarding the "burning failure" on one cylinder after an INPA scan.
At the time I couldn't work out what it meant as I didn't have a missfire. Technical German to English translations can be a bit cryptic.
The scan also came up with rough running on this cylinder as well as another - cylinders 1 & 5.
I didn't have the engine going into limp mode as yours appears to have done, although it did falter a few times but kept on going.
Turned out to be a failed fuel pump as the engine stopped completely on 2 occasions and I had to have the car flat bed towed home.
Check the fuel pump pressure via the valve on the fuel rail - just depress the valve pin and if you don't get much pressure then its probably the fuel pump or a blocked fuel filter.
It should be 3.5 bar - approx. 50 psi.
I replaced the filter first and found out it was the original dating back to 1999 when the car was built. So much for the BMW lifetime filter but I was pushing my luck a bit after 244K kms.
It was almost completely blocked as I could barely blow through it and this probably caused the demise of the fuel pump having to pump against the blocked filter.

After replacing both, fuel consumption has decreased a little and performance "seems" to have improved.

Hope this helps

[Sleepyhead97]

You should have codes

[djb2]

You can't blow through a new filter once the media is wet, so that's not a good diagnostic.

If you are curious, cut open the filter. You'll see that the media is large, and it's probably pristine. Unless you have atypically dirty fuel, it really is a lifetime filter. A failing fuel pump is far more likely than a clogged filter.

In the old days, everything was worse. Fuel came from the refinery dirty, and was stored in station tanks with open vents. Pumps didn't have filters, and the vehicle tanks were rusty and vented to road dirt. Fuel filters were tiny, and replacing them every year might not be frequent enough.

[sleuth255]

Do you have CEL? What OBD codes are stored?

[geargrinder]

Sounds to me like the cats are backing up. No where for the exhaust to go. Don't under stand why you don't have any codes though.

Lets not perpetuate the myth (especially for BMW's) that "no light means no codes"...

You should have codes

Do you have CEL? What OBD codes are stored?

Granted PO gave a big data dump so easy to lose things in it but I read...

the ECU read that there is a Burning Fail on Cylinder 1, .... Dash Displays no Engine Fail Safe mode of any sort.

I read this as "has a code, but no SES or FAILSAFE on the cluster".

Nasco the specific code or codes you got would be helpful. I'm a bit confused about the mixture stuff but perhaps if you post the actual codes and screens it might help a little.

Does seem like its a Cyl 1 issue. Plug and coil swap tends to rule out a couple things so good on you for that.

Aussie's tip is interesting. DJ is 100% right about the filters (add to your list of reasons the filter can't get clogged "the fuel pump already has a screen on it"... although you nailed the main reason filters don't clog anymore I think - plastic gas tanks don't rust & mega-fine filters built right into every gas pump...), I could see 1. it may be freak-situation possible for them to fail in some other way, like an internal collapse or seal failure, and... 2. the filter includes the fuel pressure regulator on the later cars, so on some cars "replacing the fuel filter fixed it" really probably was "replacing the FPR fixed it".

Nonetheless Aussie's experience w/ "Burning Fail on #1" and low rail supply might be worth exploring.

Beyond that, maybe bad injector (like coils - could swap pretty easily), then a couple worst case like an M54 stuck ring, or burnt valve (buddy just killed an M52B25 by burning a valve, but I want to say that was #6?).

[nasco]

Cleaned the ICV, and played with the Nipple on top of the Fuel Rail and the car at first was still doing the issue, but wasn't as bad. Then after some Italian Tuneups, the car was running like it never had before, will be looking to see if the issue comes back this weekend.

[geargrinder]

played with the Nipple on top

Can't generally go wrong there.

I mean a rare few ladies aren't into it, but overall odds are that's a winner.

[nasco]

The issue came back momentarily today, Pulled over and restarted the car. The issue immediately went away. I'm certain that this is an electrical issue at this point. Will be back with more codes and info tomorrow morning.

[capebmw]

GG, you beat me to it!!

Can't generally go wrong there.

I mean a rare few ladies aren't into it, but overall odds are that's a winner.

[nasco]

Well I have let a little bit of time pass, life caught up to me very quickly these last couple of days and in the mean time I've let the car sit for a bit. I've driven it a couple of times and every single time I've seen the exact same thing happens. Car struggles a little to start, then after starting it Idles funny, as the car warms up you feel a very noticeable misfire. Once the car is past 1/4 temp, the idle is a lot smoother. I'll drive the car around in Sport, and take the car all the way to redline, only after the 3rd or 4th 15-60 pull or after 2 or 3 WOT's will the issue show up. After one of my pulls the car completely died on me at a light, after restarting it, limping it to the side of the road and letting it idle for a minute or so the car was able to drive normally. I uploaded a Gallery of what I'm seeing on INPA as the issue appears.
There is no check engine light and my Rough Screen shows the Cylinder running within spec.
https://imgur.com/a/VMAU0 Your Responses are greatly appreciated.

[geargrinder]

I'm not an expert on M54 'normal ranges' but that looks like huge multiplicative trims to me. Which would be... (duh) vac leaks as the first item to chase.

[nasco]

I looked pretty thoroughly into the engine bay and took apart every hose I could find between the Intake Horn at the front and the Throttle Body. I'll just show up to the next nearest wrx meet and have them do their vaping business into the driver side of my Engine Bay and hopefully I can find the vacuum leak where ever it is.

[geargrinder]

I'll just show up to the next nearest wrx meet and have them do their vaping business into the driver side of my Engine Bay and hopefully I can find the vacuum leak where ever it is.

ROFL, as we used to say in the olden days.

[nasco]

I figured I should update what has happened since then.

I replaced every single portion of the Intake from the Horn in the Air Filter Housing to the Throttle Body, I have swapped ICV's and replaced all of the fuses next to the DME under the air filter. I finally got a code for an O2 Sensor Heater for Bank 1 Sensor 2. The Car was at 118k with original O2's so I'll be replacing all four of them as preventative maintenance. In addition to those services, I will be replacing the Fuel Pump, Fuel Filter, and possibly the MAF sensor. I also upgraded to the elbow connecting after the MAF from the 3-Series and also have removed the horn in the Air Box, the car sounds 20 million times better than before. Thank all of you for your responses and being so helpful.

[nasco]

Several Months later I feel I must give an update.

Turned out to be a dying Fuel Pump that would put out inconsistent fuel pressure readings. I have since run into an issue in which the Bank 2 Cat has died and as a result I now have a check engine light. I'm currently looking for a healthy cat to swap in. In addition I now have the infamous flickering oil pressure light at idle after running the car for a while on hot days and after replacing the sensor and wiring still get that error. I will be doing the OFHG soon and I hope that will fix the issue, as I have done every other gasket known to to man. Including the oil pan gasket.

This car at only 120k miles has been a really big issue and I'm looking to get rid of it soon, so it will be for sale on this forum shortly.