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blodi 01-19-2013 07:07 AM

"Increased Emissions" and running a bit rough.
I've searched as much as I can, but can't find my exact issue. I got the "Increased Emissions" warning about a month and a half ago on my 645ci. I ran a scan on it with my generic scanner and it gave me the "Coolant Below Normal Temp/Thermostat" message.
So I replaced the thermostat and reset the light. Two weeks later it comes back on, same thing, so I try replacing both of the other temp sensors on the return pipe and water pump.
This morning the light came back on.

Addtionally to this, since i got the car ~3 months ago...the car runs a little rough at idle and shakes a bit. I notice some slight surging while cruising at a constant speed too.
So, I'm wondering if I have a coil or other issue instead, but for some reason I'm getting the low coolant temp message on my non-bmw specific scanner?

Any help would be really appreciated! Oh, the car has 88K on it.

HerbP 01-19-2013 05:28 PM

The thermostat is a very common failure on these engines. If your engine is idling rough, you could have a vacuum leak. Check your 2 vent valve lines at the front of the valve covers for leaks. Another problem could be a loose oil filler cap, or the 2 crack case valves. You should be able to find plenty of info in the DIY section. You might want to look into buying some diagnostic tools for a BMW, generic readers are not much help on these cars.

Good Luck!

blodi 01-29-2013 05:30 AM

Thanks. Like I said, I replaced the thermostat. It keeps giving me that thermostat message though. Is it possible I got a bad thermostat? Is there a way to test it? I went ahead and put some techron in the tank last night as well as changed the crankcase valves and checked for leaks but found nothing. I reset the light and we'll see if it comes back on again now. I do have a BMW specific scanner coming for my laptop in a day or two now, so maybe that will tell me something more specific.

HerbP 01-29-2013 12:24 PM

With the BMW software, you can run specific test. The only bad thing about the software, is learning how to use it. One other would be to check the Coolant Temp sensor. It measures all of the coolant temp function's for the computer. It think that it is only around 20.00 or so.

Good Luck!

blodi 01-29-2013 12:28 PM


Originally Posted by HerbP (Post 7346187)
With the BMW software, you can run specific test. The only bad thing about the software, is learning how to use it. One other would be to check the Coolant Temp sensor. It measures all of the coolant temp function's for the computer. It think that it is only around 20.00 or so.

Good Luck!

I did also replace the temp sensor at the lower hose and the one at the water pump for good measure. Still got the same code again. Once the scanner gets here I hope to have a better answer.

HerbP 01-29-2013 01:49 PM

There is a DIY for the CCV valve replacement. You can pull the 2 diaphragm valves & look for cracks in the rubber. These cost around 20.00 a piece. I would also check the 2 hoses coming from the front of the valve covers, that run to the front of the intake. These crack often from dry rotting, allowing a vacuum leak.

Check these 2 items & get back with us.

Good Luck!

blodi 01-29-2013 02:57 PM

I did replace the CCV valves last night. The new ones I got did not have the nipples on the covers for the vent hoses. So I reused the old caps with new springs and diaphragms. I just now went out and started it up. I pulled the hoses off all 3 spots. That had no effect on the engine. Then I capped the nipple on the intake hose and the idle did lower. Now, I'm not sure if it was because of the engine just warming up and the idle lowering or not. I couldn't replicate that effect by pulling the cap back off. I inspected the hoses once I pulled them off and didn't notice any obvious cracks or tears. But you never know. Also didn't notice any cracks in the old diaphragms either.
I now put the new caps on that don't have the nipples on them, but just the little vent hole and have left the cap on the intake nipple. I've read somewhere before that this is supposedly an ok setup. Anyways, going to go test drive it now and see what/if any difference.
I've also read where maybe the IAT sensor could bring up the code I have posssibly. Where is that located?
Thanks for all the help so far!

HerbP 01-29-2013 08:47 PM

The IAC valve would be located on the left side of the intake I think, on the throttle body. It looks like a motor, with a electrical plug going to it. The IAC opens as needed to allow air to pass, to set the idle. I don't think it would be your problem, but the port that it meters could be clogged. I may have some pics somewhere if needed.

Good Luck!

blodi 01-30-2013 07:19 AM

Maybe I'll take a look at the IAC valve when I get a chance.

Driving the car last night the idle still seemed a bit rough. I noticed sometimes its hovering around 500 rpm and other times at around 700 rpm. The whole car really feels shaky at times. You can see the tach needle bouncing too, so I know its not just me.

blodi 03-07-2013 05:11 AM

Just thought I'd update this. I replaced the thermostat again, making sure I got an OEM Wahler brand this time. It's been a couple of weeks and I have not had the error message since. I've also notice my oil temp gauge seems to be reading higher. So I think I might have just have gotten a faulty thermostat the first time I replaced it. Hopefully that was it.

As far as the roughness, I am going to check out the engine/trans mounts as I noticed a slight knocking sound from the trans tunnel if I put the car in manual mode and am on/off the throttle. Anyone ever have a mount go bad?

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