BMW 318ci Throttle revving by itself

babel

Hi,

Brought my car for an oil change and coolant top up last friday. Drove it away fine. The next morning when I started the engine, the throttle started revving by itself up to 2,000 rpm. This continued for about a minute and then stopped revving. It hasnt happened since but I have noticed that when I start the engine it revs at around 1,000 for the first few minutes before dropping down to around 500 rpm (which I think is what it normally idles at). Does anybody have any ideas what could have caused this?

Thanks

Mitch Connor

If the oil was changed, they could have used a pressure hose to clean the engine (in case of oil spilling) As a result of this, some water may have got into the angine/spark plugs - something along those lines which could cause the symtoms you are talking about.

Happened to my car a while back after an oil change and the car acted funny for a few days til the water evapourated out.

On the other hand, I could be talking balls (unintentionally)

cantdecide

Is it revving up and down ie hunting?? What year and mileage?

MAF sensor/ lambda maybe??

babel

cantdecide wrote: »

Is it revving up and down ie hunting?? What year and mileage?

MAF sensor/ lambda maybe??

It is a 2002 with 75,000 miles. It probably revved between 1500 and 2200 climbing and dropping between these two limits. It hasnt done it since but I do think the idle revving at 1000 rpm at engine startup only happened since then

hopchop

I had a 1995 BMW 318is and it did that also, it most likely is the throttle sensor, BMW's in general are known for giving throttle sensor problems.

cantdecide

hopchop wrote: »

I had a 1995 BMW 318is and it did that also, it most likely is the throttle sensor, BMW's in general are known for giving throttle sensor problems.

My old '91 E36 325i had a knackered lambda that caused those symptoms

Caveat

Is idle control valve the same thing as throttle sensor?

If not, could also be the ICV - easy to fix. If they are the same thing - I'll get me coat

cantdecide

Caveat wrote: »

could also be the ICV - easy to fix

AFAIK, it's not even a question of repairing it- I think it just has to be cleaned.

Caveat

cantdecide wrote: »

AFAIK, it's not even a question of repairing it- I think it just has to be cleaned.

Yes you are right - badly worded post of mine. I suppose I meant 'easy to fix the problem' ... i.e. by cleaning it

babel

thanks guys, I will have a look into that.

mickdw

yep, maf sensor in line after air filter or split pipe on air intake side most likely

bmw323ci

Mitch Connor wrote: »

If the oil was changed, they could have used a pressure hose to clean the engine (in case of oil spilling) As a result of this, some water may have got into the angine/spark plugs - something along those lines which could cause the symtoms you are talking about.

Happened to my car a while back after an oil change and the car acted funny for a few days til the water evapourated out.

On the other hand, I could be talking balls (unintentionally)

i have a 99 bmw 323ci e46 and for some reason its revs its self in 3rd 4th and 5th to 6000 rpm but is fine in 1st and 2nd iv changed throttle body already and lambda sensors but still not fixed can anyone that might have ever had this problem tell me how it can be fixed thanks

Nissan doctor

bmw323ci wrote: »

i have a 99 bmw 323ci e46 and for some reason its revs its self in 3rd 4th and 5th to 6000 rpm but is fine in 1st and 2nd iv changed throttle body already and lambda sensors but still not fixed can anyone that might have ever had this problem tell me how it can be fixed thanks

This thread is 4 years old.

But if the car is revving while your accelerating in gear then its likely to be a clutch issue.

bmw323ci

car is not reving while im in gear its when i take it out of gear that it starts to rev to 5000rpm some times 6000rpm after a certain speed in 1st and 2nd drives very well and while its stoped is fine as well its just when im in 3rd 4th and 5th and i take it out it revs its self like mad

anthony4335

If you got the coolant topped up, it might be an airlock in the system. You may need to bleed the system. 2 plastic screws one just in front of the expansion tank where you top up the other ,the other 4 inches in front of that. I might take a while to bleed.

Nissan doctor

anthony4335 wrote: »

If you got the coolant topped up, it might be an airlock in the system. You may need to bleed the system. 2 plastic screws one just in front of the expansion tank where you top up the other ,the other 4 inches in front of that. I might take a while to bleed.

This thread won't continue I'm sure once a mod see's it but by the stretch of what imagination could a cooling system air lock cause the engine to rev?

TestTransmission

zombie thread.