bmw idiling probs
- Thread starter dangttdi
- Start date
How old is the car? If it has an ECU, it could have developed a fault.
You can normally reset the ECU but disconnecting your battery for a period of time.. (Some people say 30mins, some people say over night).. Once you start it up again, leave the car to idle for 5minutes, and then drive the car around for 15mins at various rev-ranges to let the little clever box do all of it's mystical tricks! It should adjust itself to how it thinks it runs best, given what information it recievs from your engine sensors.. [CHECK YOUR OWNERS MANUAL FIRST IF YOU ARE UNSURE OF THIS PROCEDURE!!]
Here is where the fault MAY lie.. If you have faulty sensors, then the ECY is getting incorrect signals, and this may be why your engine is idling incorrectly.. It could be your idle control sensor (or stepper motor), or it might be your trottle postition sensor.. I'm sure there are alot of other sensors which could be responsible, but these are the two which spring to mind!
The problem could also be due to a build up of dirt in your throttle inlet. If you have some mechanical knowledge, you could remove your airbox, and use a cloth (best to use something like nail varnish remover on it aswell!) and wipe around the inlet, whilst holding the butterfly open. If you put the cloth on the end of a screwdriver you can get a bit further down and give that a good clean too!
It's best to start the engine after this (hopefully it's warm) and give it a good revving! If it's not warm, let it idle and get the oil temp up before you give it too many rev's! You could also use some carb and injector cleaner to help clear it out. You spray this stuff into the inlet while the car is idling, and it help removes the build up of dirt in your throttle plenum, as well as on the sensors, and in your injectors. Just spray short bursts in while you idle the car, and occasionally give it a blast of the throttle. Best to do both of these jobs at once, while the air box is off.
A bit fo reading there! Hope something helps! I've had idling problems with my car, and I know it can be a bugger! Can't say mine have gone away 100%, but I don't notice them now, so at the moment it's not an issue for me!
Freddie
You can normally reset the ECU but disconnecting your battery for a period of time.. (Some people say 30mins, some people say over night).. Once you start it up again, leave the car to idle for 5minutes, and then drive the car around for 15mins at various rev-ranges to let the little clever box do all of it's mystical tricks! It should adjust itself to how it thinks it runs best, given what information it recievs from your engine sensors.. [CHECK YOUR OWNERS MANUAL FIRST IF YOU ARE UNSURE OF THIS PROCEDURE!!]
Here is where the fault MAY lie.. If you have faulty sensors, then the ECY is getting incorrect signals, and this may be why your engine is idling incorrectly.. It could be your idle control sensor (or stepper motor), or it might be your trottle postition sensor.. I'm sure there are alot of other sensors which could be responsible, but these are the two which spring to mind!
The problem could also be due to a build up of dirt in your throttle inlet. If you have some mechanical knowledge, you could remove your airbox, and use a cloth (best to use something like nail varnish remover on it aswell!) and wipe around the inlet, whilst holding the butterfly open. If you put the cloth on the end of a screwdriver you can get a bit further down and give that a good clean too!
It's best to start the engine after this (hopefully it's warm) and give it a good revving! If it's not warm, let it idle and get the oil temp up before you give it too many rev's! You could also use some carb and injector cleaner to help clear it out. You spray this stuff into the inlet while the car is idling, and it help removes the build up of dirt in your throttle plenum, as well as on the sensors, and in your injectors. Just spray short bursts in while you idle the car, and occasionally give it a blast of the throttle. Best to do both of these jobs at once, while the air box is off.
A bit fo reading there! Hope something helps! I've had idling problems with my car, and I know it can be a bugger! Can't say mine have gone away 100%, but I don't notice them now, so at the moment it's not an issue for me!
Freddie
thanks its a e46 1999 t reg if that help ive stcuk redex in it gonna wait for it to run through first.
when you sed spray something in the inlet valve what did you mean to spray in? also do i spray it in after the MAF while the airbox is off.
I should really take it to bmw but they charge and arm a leg to even look at it.
thanks
when you sed spray something in the inlet valve what did you mean to spray in? also do i spray it in after the MAF while the airbox is off.
I should really take it to bmw but they charge and arm a leg to even look at it.
thanks
You spray it directly into your throttle inlet, after the you've taken off the airbox, so after the MAF..
I use WYNN's carburetor and injector cleaner, but a similar product would do. I've heard some people even use WD40, although this doesn't sound like a good idea to me!!
Taking it to a dealer will cost you, so you might aswell try to fix it yourself.. As long as you are quite confident you know what you are doing, and by the sounds of it you know a bit about cars. I've done this on my car without any problems, but if you are at all worried, at least ring the garage up first.
I use WYNN's carburetor and injector cleaner, but a similar product would do. I've heard some people even use WD40, although this doesn't sound like a good idea to me!!
Taking it to a dealer will cost you, so you might aswell try to fix it yourself.. As long as you are quite confident you know what you are doing, and by the sounds of it you know a bit about cars. I've done this on my car without any problems, but if you are at all worried, at least ring the garage up first.
the_names_james
Torque Junkie
- Points
- 70
- Location
- Surrey, UK
I'm not sure the car will even idle without the MAF present.
the_names_james
Torque Junkie
- Points
- 70
- Location
- Surrey, UK
I don't know, usually it goes Airbox > MAF > Throttle. Surely the ecu will need to know how much air is entering the engine..
Does the BM have a MAP sensor?
Is there an idle adjustment screw?
Does the BM have a MAP sensor?
Is there an idle adjustment screw?
You are getting a bit past my knowledge now! If you are correct, and the sensor is after the airbox, I would imagine that the car would run without the MAF sensor, as people would not be able to replace the air box with an aftermarket air filter without some sort of bypass system..
As for your other questions I can't really help.. You could try looking for a e46 forum, such as http://forum.e46fanatics.com/
Sorry I can't be of more help to you! If you get any further towards the source of your problem, please come back and let us know!.. And if you fix it, tell us how you or the mechanics did it!
As for your other questions I can't really help.. You could try looking for a e46 forum, such as http://forum.e46fanatics.com/
Sorry I can't be of more help to you! If you get any further towards the source of your problem, please come back and let us know!.. And if you fix it, tell us how you or the mechanics did it!
the_names_james
Torque Junkie
- Points
- 70
- Location
- Surrey, UK
No no, look at my username, it's not me with the BMW 
Basically, when I used 10k boost on my Swift, the car really didn't like the MAF being removed, it wouldn't idle properly, and trying to give it some throttle would stall the engine.
As for aftermarket filters and MAF bypassing (?!) why not just bolt the filter to the MAF like:
dangttdi - does the car have an idle adjustment screw?
Basically, when I used 10k boost on my Swift, the car really didn't like the MAF being removed, it wouldn't idle properly, and trying to give it some throttle would stall the engine.
As for aftermarket filters and MAF bypassing (?!) why not just bolt the filter to the MAF like:
dangttdi - does the car have an idle adjustment screw?
You can spray past the MAF using a simple extension tube - make sure it doesn't snap though. That way the MAF stays in place and the spray goes to where it's needed. Ecoteck power boost spray is pretty good at cleaning out emulsion from engines.
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