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Discussion Starter #1
Hello ladies and gentlemen.

I have noticed recently that my red oil light has been flickering at idle. As I have posted before, I'm having a rough rpm problem. With the MAF unplugged, it idles at about 600-650 rpm, which is a bit too low (I think its supposed to be at like 750). It only comes on when the car is warmed up. As soon as the rpms go up past 700, the red oil light goes away completely. as soon as the idle drops back down again, the light flickers rapidly again. I'm not too sure if I should be concerned. I did recently do an oil change myself, with an OEM filter. Either way, I have ordered a Foxwell scanner and I will read the MAF live data and see if thats the cause of the low idle.

Thanks for any help!
 

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When you did your oil, did you add the required 7 or 8 qts. or drain and fill to the max line on your dipstick?

I suspect you're low on oil even if your dipstick says your fine. My car had picked up a wrong dipstick somewhere along the way...I was 5/8ths qt. low on oil for a year or two (no harm done).

It's always safest to trust sensors--they're usually right.
 

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When you did your oil, did you add the required 7 or 8 qts. or drain and fill to the max line on your dipstick?

I suspect you're low on oil even if your dipstick says your fine. My car had picked up a wrong dipstick somewhere along the way...I was 5/8ths qt. low on oil for a year or two (no harm done).

It's always safest to trust sensors--they're usually right.
I put 6.6 quarts in it... its not at the maximum line. I don't think this has to do with the level, it may but I don't think so. I should top it off with another half quart or something... I did try to follow the owner's manual (which says 6.6 quarts).
 

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Hello ladies and gentlemen.

I have noticed recently that my red oil light has been flickering at idle. As I have posted before, I'm having a rough rpm problem. With the MAF unplugged, it idles at about 600-650 rpm, which is a bit too low (I think its supposed to be at like 750).
This is normal behavior. Keep the rpm up to have proper pressure, and fix the low rpm issue.
 

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2003 325xi 5spd Manual
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Normal-ish behavior...

Manual tranny car, if I release the clutch too fast without revs, but slow enough that it doesnt outright stall, I can sometimes get the oil light to flicker, but that is when its down to like ~200 RPM. Battery light will flicker too.

You may have a mild issue with oil pressure.
 

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Hello ladies and gentlemen.

I have noticed recently that my red oil light has been flickering at idle. As I have posted before, I'm having a rough rpm problem. With the MAF unplugged, it idles at about 600-650 rpm, which is a bit too low (I think its supposed to be at like 750). It only comes on when the car is warmed up. As soon as the rpms go up past 700, the red oil light goes away completely. as soon as the idle drops back down again, the light flickers rapidly again. I'm not too sure if I should be concerned. I did recently do an oil change myself, with an OEM filter. Either way, I have ordered a Foxwell scanner and I will read the MAF live data and see if thats the cause of the low idle.

Thanks for any help!
Normal idle is about 750. Maybe you should spend some time lookinig at your engines overall health to see why it is idling badly eg: fuel trims, vacuum leaks that sort of thing. Use the scan tool to find out what your long and short term fuel trims are and post them on here for discussion.
 

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I put 6.6 quarts in it... its not at the maximum line. I don't think this has to do with the level, it may but I don't think so. I should top it off with another half quart or something... I did try to follow the owner's manual (which says 6.6 quarts).
You should probably mention what model you have. I know most e46s take 6.9 qts/ 6.5L or the Xi's take 8 qts.

...as far as it being normal...I believe that Sapote meant that when your engine is nearly stalling and things aren't working as they should, oil pressure will drop. Your light flickering is doing what it should be doing because something else isn't.

Not sure of the state of your maintenance, but if you have a low idle, start with maintenance and do the things your car needs--plugs, filters (including fuel), and clean your idle control valve and throttle body. (Low idle is often icv...and replace the lower intake boot as I can feel it needs a replacement. :) )

When you get your Foxwell, read your codes
 

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Discussion Starter #9
You should probably mention what model you have. I know most e46s take 6.9 qts/ 6.5L or the Xi's take 8 qts.

...as far as it being normal...I believe that Sapote meant that when your engine is nearly stalling and things aren't working as they should, oil pressure will drop. Your light flickering is doing what it should be doing because something else isn't.

Not sure of the state of your maintenance, but if you have a low idle, start with maintenance and do the things your car needs--plugs, filters (including fuel), and clean your idle control valve and throttle body. (Low idle is often icv...and replace the lower intake boot as I can feel it needs a replacement. :) )

When you get your Foxwell, read your codes
Hmm I didn't know they took 8 quarts. Anyway, yes I believe it is just the rough idle causing the light.

As far as the rough idle, I've changed my spark plugs (not coils),my oil and oil filter, cleaned the idle air control valve and literally had to replace the DISA valve because the motor shaft was completely snapped off.There is no blowing or sucking from the oil fill cap, the ccv seems normal. I also checked the intake boots, and they are all clean (they almost look brand new lol). I did try to replace the MAF but it didn't help at all (I bought and aftermarket one.) I'm going to get my scanner and read the maf live data to see if both old and new maf sensors are dead. My car is also very old, 224,000 miles (still shifts and generally does great at rpms higher than 750 rpm). When I did the oil change, I put 6.6 quarts in. The dipstick shows halfway, no oil consumption. I am thinking of putting another quart in to get rid of the YELLOW oil light, which sometimes comes on if I'm sitting on an incline.

EDIT: also, my car is a 2003 BMW 325xi.
 

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Yep, you sound like you're low on oil...Xi's take a qt. more oil than other e46s...I'm almost positive...though haven't confirmed myself. My 328i went 386K miles...and it was still young when bmw squashed it. Sigh.

Anyway, your oil light is flickering because you're low on oil...and red because it's seriously low. The yellow light on an incline also tells me you're low.

Your idle being low is something else, though, I'm pretty sure.
 

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E30M3 Race F10 535 R1150Rt M Coupe
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A couple of thoughts:

Yellow oil light is a level issue. No biggie, just top off. A red light is not seriously low, rather it's a dynamic issue and the oil pressure measured at the sensor is below threshold.
The oil pressure light performs two functions. Just to be clear for the uninitiated, red is not the next stage of yellow, rather a pressure issue.

There is no blowing or sucking from the oil fill cap, the ccv seems normal

Incorrect. The engine when operating normally should have vacuum under the oil cap. In fact is should be 13 mBar on a fully warmed up engine @ idle. It's what makes the CCV system work.
 

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Discussion Starter #13
A couple of thoughts:

Yellow oil light is a level issue. No biggie, just top off. A red light is not seriously low, rather it's a dynamic issue and the oil pressure measured at the sensor is below threshold.
The oil pressure light performs two functions. Just to be clear for the uninitiated, red is not the next stage of yellow, rather a pressure issue.

There is no blowing or sucking from the oil fill cap, the ccv seems normal

Incorrect. The engine when operating normally should have vacuum under the oil cap. In fact is should be 13 mBar on a fully warmed up engine @ idle. It's what makes the CCV system work.
what I mean is there is no excessive sucking. It has vacuum, but its not excessive. The rpms go down when I detach the oil fill cap.
 

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Discussion Starter #14
Thank you, Don! OP...I do think you need both oil and to bring your rpms up at idle and hope you figure it out soon!
Looks like I'll be topping it off. Still looking forward to getting my scanner and scanning the MAF. Thanks for the replies everybody!
 

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Looks like I'll be topping it off. Still looking forward to getting my scanner and scanning the MAF. Thanks for the replies everybody!
Your first job is to clean the idle control valve. That will probably sort it out. This guy says you don't have to remove teh cabin filter which is true on some cars. On others, like mine, I do have to remove it because I need to remove the cover in the corner so I can pull my DISA out. Anyway watch this. Other vids are avaialble for this DIY.

 

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I'm really curious about the whole idle valve thingy.
I've been working on these cars since they were new. I can only recall 5 or less times we've had any issues with them. Be it soft or hard fail.

If we have it off, we clean it. But that's all. Just not had any issues in 20 years.
 

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I'm really curious about the whole idle valve thingy.
I've been working on these cars since they were new. I can only recall 5 or less times we've had any issues with them. Be it soft or hard fail.

If we have it off, we clean it. But that's all. Just not had any issues in 20 years.
Think of it like a choke. In the old days a choke would be a flap in the intake between the carburettor and the inlet manifold. It would be cable adjusted originally. You would pull the cable from inside the car to adjust air flow and therefore air/fuel mixture. This would normaly be required for cold starts where fuel mist would condense on the cold manifold instead of entering the pistons. You would close the choke to compensate and open it up when you were at normal operating temperature. If you forgot to do so you could flood the engine. ie: wet the plugs with fuel. Eventually the cable disappeared and was repaced by a bimetal coil that would be heated by the coolant closing and opening automatcally as the engine reached normal temperature. The ICV does the same thing but is controlled continuously be the DME which responds to various signals from sensors including the intake air temperature sensor. If the valve is gunged up and unable to move then you can have idle problems. So you clean it to make sure it can move freely as indicated by the clicking sound when you waggle it from side to side. If you live in an environment where the air temperature and pressure hardly varies throughout teh year it is possible your ICV would have little to do and the fact that it isn't working properly might go unnoticed.
 

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Thanks, albeit I fully understand the operation. Furthermore did you know that on extended periods of WOT it goes full open to allow more air. Also if your accelerator pedal/throttle potentiometers go bad the DME lets you lump home on the ICV.

I was speaking to the number of times guys remove them and clean it to solve an issue. I stated beforehand that I've seen VERY little issues with such.
 

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Discussion Starter #19
Think of it like a choke. In the old days a choke would be a flap in the intake between the carburettor and the inlet manifold. It would be cable adjusted originally. You would pull the cable from inside the car to adjust air flow and therefore air/fuel mixture. This would normaly be required for cold starts where fuel mist would condense on the cold manifold instead of entering the pistons. You would close the choke to compensate and open it up when you were at normal operating temperature. If you forgot to do so you could flood the engine. ie: wet the plugs with fuel. Eventually the cable disappeared and was repaced by a bimetal coil that would be heated by the coolant closing and opening automatcally as the engine reached normal temperature. The ICV does the same thing but is controlled continuously be the DME which responds to various signals from sensors including the intake air temperature sensor. If the valve is gunged up and unable to move then you can have idle problems. So you clean it to make sure it can move freely as indicated by the clicking sound when you waggle it from side to side. If you live in an environment where the air temperature and pressure hardly varies throughout teh year it is possible your ICV would have little to do and the fact that it isn't working properly might go unnoticed.
I already did clean the ICV valve, thats how I discovered the DISA valve was broken- I removed the DISA valve to get to the ICV.. It was pretty caked with carbon and stuff. that went back in and that operates good.

Good news is, today I am finally going to get my scanner. Only problem is, my ignition switch decided to die on me just yesterday. I'll be buying a new one shortly.
 

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I already did clean the ICV valve, thats how I discovered the DISA valve was broken- I removed the DISA valve to get to the ICV.. It was pretty caked with carbon and stuff. that went back in and that operates good.

Good news is, today I am finally going to get my scanner. Only problem is, my ignition switch decided to die on me just yesterday. I'll be buying a new one shortly.
So, I finally got my scanner. Plugged it into the OBD port (the car won't start because bad ignition switch), and got 9 codes. the first 7 were 'misfire detected on [insert number here] cylinder' and the other 2 were 'too lean' codes. Since I can't start it, I can't look at my live data. That'll have to wait for 2 days.

I will report back here then once I can start it up.

Cheers!
 
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