[SOLVED] Got gas, drove 45 minutes, then increased emissions and limp mode?

[Rat3d ///M]

EDIT: This is an old thread. Someone bumped it up but it's no longer relevant. FWIW, my issue after months of dealing with it trying to figure it out ended up being an exhaust leak before the driver side cat. The donut gasket between the driver cat and the header was completely gone. Replaced it when I installed my test pipes and never had an issue again.

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Today I decided to take the ///M for what will likely be one of the last drives for the season before she goes into storage. It's been about 2 weeks since she has been out of the garage. I was low on gas, so I went to the gas station and filled it up about 3/4 of the way. I drove about 10 miles, then made a couple stops, and suddenly, dashboard lights up like a Christmas tree.

"Increased emissions" warning, "Engine Malfunction: reduced power" warning (i.e. limp mode). Car was running a little rough (though not too bad) and sounded noticeably different. So, I drove a mile or so, pulled over, turned the car off, got out, locked it, got back in, and started it up. Everything was normal again. Drove off, and 2 minutes down the road, same exact thing.

At this point, I was about 2 minutes from where I was headed, so I drove the rest of the way, parked the car and after a little over an hour, I came out and got in it and started it. Car immediately came up with the increased emissions warning (but no limp mode this time). I drove about 15 minutes home, and the warning stayed on the entire time, but never went into limp mode thankfully. When not in limp mode (even with the increased emissions warning on) the car seems to run and idle as normal. Nothing out of the ordinary until it kicks into limp mode, then it has a slightly rough idle and noticeably different exhaust tone (almost sounds deeper and more sputtery?)

The car is in the garage now, haven't tried to start it again since I got home (I suspect nothing will have changed). I have someone coming over in a little bit to check the codes, but in the meantime, I was wanting to get some preliminary advice on what this sounds like. I know it could be one of several things from bad gas to faulty o2 sensors to dirty MAF (or so I have read). Given that I put gas in the car 45 minutes prior to this starting, that is a likely suspect, but I just can't imagine bad gas causing this. I thought that was just something people said as a "gee wizz" thing when something like this happens

Any ideas? I will post codes when I get them.

[dparm]

Until we see the codes, anything will just be a guess. OBD2 is a fickle beast and it might be nothing.

[TomHudson]

No MAF in your car.

Since we are guessing without codes, I'm going with throttle actuator(s) for $100 Alex....

[thekurgan]

This sounds like the fuel tank purge valve thing.

[roastbeef]

Sounds like the time my brake vacuum hose took a dump.

[Bavarian Beast]

How old is your battery?

[Rat3d ///M]

Battery is original, but I keep it on a CTEK when not in use (not that that means much).

Update: had the codes ran, and it had several engine misfire codes, all on cyl 5-7 (one bank). This leads me to believe throttle actuator (FML). However (dot comma), a local guy (not sure if he is on here or not) had the same misfire codes a few weeks ago after filling up with gas. He had his codes cleared, put in 100 octane and fuel injector cleaner, and hasn't had a problem since (been about 3 weeks). I cleared my codes, and took an 8 mile drive to the store to buy some fuel injector cleaner, and then an 8 mile drive back home, and the car ran flawlessly, no codes, no nothing. I even pushed the car a bit on my journey.

So I am leaning toward two things: bad gas (hopefully), or throttle body actuator. I am going to run 100 octane once I get down to half a tank, put in the fuel injector cleaner, and hope all is good. If not, I will look into other things, like throttle body actuator, etc.

I guess my question at this point is, given my scenario where the codes haven't come back yet and I just filled up my tank 30 mins before this started, is it likely that it's bad gas rather than the throttle body actuator, or is the codes taking a little while to come back after clearing them common with the throttle actuator malfunctions people are seeing?

If it is in fact the throttle actuator, I guess I will add that as a winter project along with the Brembo setup I was planning

[Prince_of_Persia]

This is exactly what happened to me when my throttle actuator had to be replaced.

[Rat3d ///M]

I forgot to mention, I've noticed lately that my exhaust sounds different somehow. I think I might have even posted about it lately. I can't really explain how it sounds different, but I attributed it to the changing weather (getting colder out) or thought maybe it was all in my head. I had someone else tell me it sounds as though the exhaust is different than what a regular OEM exhaust modded M3 should sound like (had him say it without me even mentioning it first).

I read that a change in exhaust note can be a telltale sign of a bad CPS. Any input on this or if that might be causing my misfire issue?

Also had an intermittent issue a couple times (thought not lately) where the car would crank over repeatedly and fail to start. Had to press the ignition switch again to stop it after 4-5 seconds, then try again, and which time it started fine. Read somewhere this is also indicative of a bad CPS?

[duk]

throttle actuator

[Rat3d ///M]

Originally Posted by duk

throttle actuator

Yep, thats what I am leaning toward too. I tried to convince myself otherwise, but I am just lying to myself I think Looking into options for replacing the gears opposed to buying new actuators now.

Here are my fault codes that came up.

[Bavarian Beast]

Good luck. If you want company (or tools) changing something let me know if I can help.

[nick3753]

Your baby is just pissed about having to be put in storage.

[stevelp99]

Same thing happened to me a few weeks ago, got gas in the morning (shell gas), went to my indy mechanic for oil change, (Brand new Engine from BMW so it was the engines first oil change). Afterwards in the parking lot as I was leaving it threw same codes, Misefire 5-8, misfire imparing emissions, misfire with cutout several cylinders., rough idle, reduced power. Actually the car cut fuel to cylinders 5-8 completely. First we checked for anything that might of come loose. Then My indy hooked up an autologic to pull codes and read various readings. We first thought O2 sensor as at one time we pulled an O2 sensor precat code, but only once. so we tried changing the senor which didn't fix anything. We thought that maybe a coil pack might of gone bad, though I don't see how it would of caused an entire bank to go offline, But we tried swapping those too, same result. Lastly we figured it must of been fuel related as when the car first starts we were getting good fuel and ignition readings via the autologic, but after a min or 2 of idling we get codes and limp mode. I left the car for my Indy to sort out, He threw in some fuel system cleaner and let it idle for a a bit, then after a restart problem solved. The best we could assume was that it was either bad batch of fuel or some debris clogged up a fuel like or sensor or something along those lines. We didn't have any other codes to go by as the O2 code only showed once, and we didn't see any other codes that others have had indicating an actuator or other sensors, plus the engine only had about 1500 miles on it so it shouldn't of been the actuator. My Indy and I didn't want to just start throwing money at it unless we had a clue as to where the problem was coming from. Either way the car has been working perfectly for the last 2 weeks since, changed gas stations for a bit and after a fill up today still running strong.

Seeing as you have as little information to go off of I would suggest trying some fuel system cleaner. From there check spark plugs and coil packs. Then you can start playing with actuators and such.

[Rat3d ///M]

Originally Posted by Bavarian Beast

Good luck. If you want company (or tools) changing something let me know if I can help.

Thanks John. I will probably take you up on that. It looks like a pretty easy job, but having an extra set of hands is never a bad thing.

Originally Posted by stevelp99

Seeing as you have as little information to go off of I would suggest trying some fuel system cleaner. From there check spark plugs and coil packs. Then you can start playing with actuators and such.

Your post gives me slight hope. I guess I am just fearing the worst, and trying to bring myself to the idea that I have to spend $1800 fixing it. That was a large chunk of my BBK budget for my winter storage project. I find it so weird that a lot of these reports of this happening lately are after getting gas. Coincidence? I did buy some fuel injector cleaner, so I am still going to run it down to half a tank, and put in 100 octane and the fuel system cleaner and see what happens. The guy local to me that the same thing happened to (almost same exact codes I think) did this 3 weeks ago and hasn't had a problem since. It's my understand that if it's the throttle actuators the codes will eventually come back, and I have read one case where it was less than 50 miles later. Also, my spark plugs have less than 4000 miles on them, so I wouldn't think that would be it, but I won't rule out coil packs either.

So my game plan as of now is:

1. Drive the car down to half a tank, put in fuel system cleaner and 100 octane, and continue to drive the car as much as possible. See if codes come back. If not, all is good I guess?

2. If codes come back, take throttle actuators out and visibly inspect the circuit boards and gears. Switch throttle actuators to see if misfire switches sides. If so, I guess I found my issue.

My only concerns are, from what I understand, the reason they fail, is that the gears tend to slip over time, which causes the electronics to work harder and overheat, which ultimately causes the MOSFETs to fry. They can be replaced if you are handy with a soldering gun, but eventually they will cause the board to fail beyond repair. At this point I am not getting a throttle actuator code, just the misfire code, which leads me to believe if it is the TA, it is just the gears, and they can be replaced for a couple hundred rather than a couple thousand. If I keep driving the car, I am afraid I will do more damage and eventually cause them to be irreparable.

A potential good part of all this, is I live in Germany, and from what I have seen, BMW parts seem to be a little cheaper here from the dealer (possibly because they are made here?). Plus, being US Military, I don't pay their VAT tax, so I get 19% off whatever they cost. I think I will check the dealer for price. I might be able to save a few hundred from what they typically cost. I still have to pay the ///M tax though. No form that I can fill out to save me from that.

[stevelp99]

The only thing with coil packs is that its unlikely that all bank 2 coil packs would go at the same time causing that many misfires. I think it looks like based on you codes your engine may be cutting fuel to those cylinders. Hopefully your issue is something easy and cheap. Best of luck.

[MachinesWithSouls]

I hope this does not sound like bullshit, but here goes.

On my car, I will get this "Increased emissions" warning, followed by my idle getting wobbly for a bit. But the car runs fine. Long story short, I traced mine back to the battery.

I'm still on my original battery, which I do charge, but still. Anyway, since the car sits a lot, if I drove it on short trips or would sit in the car with the engine off and listen to the stereo, this short little drains on the electrical system would trip that SES light. Every time it happened, I put the car on the charger for a night and it went away the next day.

Long story short, try charging it for an overnight and take it on a longer trip, without turning it off to use any of the electrical systems. Best advice I could offer.

[Wyattearp]

Originally Posted by stevelp99

Same thing happened to me a few weeks ago, got gas in the morning (shell gas), went to my indy mechanic for oil change, (Brand new Engine from BMW so it was the engines first oil change). Afterwards in the parking lot as I was leaving it threw same codes, Misefire 5-8, misfire imparing emissions, misfire with cutout several cylinders., rough idle, reduced power. Actually the car cut fuel to cylinders 5-8 completely. First we checked for anything that might of come loose. Then My indy hooked up an autologic to pull codes and read various readings. We first thought O2 sensor as at one time we pulled an O2 sensor precat code, but only once. so we tried changing the senor which didn't fix anything. We thought that maybe a coil pack might of gone bad, though I don't see how it would of caused an entire bank to go offline, But we tried swapping those too, same result. Lastly we figured it must of been fuel related as when the car first starts we were getting good fuel and ignition readings via the autologic, but after a min or 2 of idling we get codes and limp mode. I left the car for my Indy to sort out, He threw in some fuel system cleaner and let it idle for a a bit, then after a restart problem solved. The best we could assume was that it was either bad batch of fuel or some debris clogged up a fuel like or sensor or something along those lines. We didn't have any other codes to go by as the O2 code only showed once, and we didn't see any other codes that others have had indicating an actuator or other sensors, plus the engine only had about 1500 miles on it so it shouldn't of been the actuator. My Indy and I didn't want to just start throwing money at it unless we had a clue as to where the problem was coming from. Either way the car has been working perfectly for the last 2 weeks since, changed gas stations for a bit and after a fill up today still running strong.

Seeing as you have as little information to go off of I would suggest trying some fuel system cleaner. From there check spark plugs and coil packs. Then you can start playing with actuators and such.

I have a feeling that my Engine Malfunction warning with reduced power, is likely from bad gas.

One week ago I filled up and within 2-3mi the car started revving itself when I stopped at a light. This happened a few times until it finally shut off. It came back on no problem and no further issues until today. I let the car rest for 10 minutes after the malfunction warning came on and it has not came back yet. I still have to drive home and then the shop on Thursday.

If it is bad gas, could filling up the last 1/4 tank with better quality improve the situation at all or does it need to be fully drained? Also, what is the overall consensus on using fuel system cleaner? I have always thought those were bad for an engine if overused, however, with my current situation I was thinking about using it. Trying to focus on best options before getting my car into the shop to see what is really the issue.

Cheers,

[Mvy]

If its TAs, dont forget you can use the less expensive M5 TAs and just switch out a couple parts to make it work on your S65. I think the difference is 500 bucks a TA vs 1000.

[Iyzmi]

Originally Posted by Rat3d ///M

Yep, thats what I am leaning toward too. I tried to convince myself otherwise, but I am just lying to myself I think Looking into options for replacing the gears opposed to buying new actuators now.

Here are my fault codes that came up.

I'd be surprised if it turned out to be bad gas. Once you conclude that it is in fact the throttle actuator(s), don't waste your time replacing the gears. That solution has been shown to work less than half the time based on many posts here by people who have tried that fix. Also don't rely on a visual inspection of the gears and circuit board. I had a brand new throttle actuator (replaced by the dealer) fail after only ~1yr/5k miles; both the circuit board and gears looked brand new.

[Kamen]

Originally Posted by Mvy

If its TAs, dont forget you can use the less expensive M5 TAs and just switch out a couple parts to make it work on your S65. I think the difference is 500 bucks a TA vs 1000.

Where do you find S85 TA for ~$500? I've been searching the web, but cheapest I found is around 750

[Tracyis300]

It could be the fuel pressure sensor going bad? I had the same symptoms and same codes pop up. After i cleared them and drove the car for a bit, the emissions warning showed up again but only one code showed up and it was for the fuel pressure sensor.
It's a $80 part, and very simple to install