E46 M3 owners - a little request!

[Pig Skill]

Guys

I am trying to work through a small niggle with the M3. It's a 2002 27k miles car that is in good order.

However there is an annoying hesitation that can be created when driving in a certain way and I want to determine if it's a characteristic or a fault so I am asking if any other E46 M owners with Manual transmission can dot he following and report back

Drive along in either 2nd or 3rd and ensure the rpm is below 2k, ideally 1500ish then floor it by quickly burying the throttle i.e. not progressively but more of a stamp.

What happens with mine and anothers car is this - it hesitates or stutters a little in the same way a conventional automatic car would before dropping a cog. After the hesitation it accelerates hard right to the limiter.

This ONLY happens in 2nd and 3rd.

I have done the usual searching and I think it may be a characteristic rather than a fault but if others could try it and report back I would be very grateful.

Many thanks in advance

Edited by Pig Skill on Sunday 20th November 17:01

[Nedzilla]

I think its just the way they are.I have noticed this in mine,from about 1000rpm to 1750ish it does feel very flat.You do only really notice this if,as you say you stamp on the throttle because all of a sudden at just under 2000rpm it suddenly jumps into life and surges forward.On a progressive throttle you dont really feel it.

You probably only notice it in 2nd and 3rd as in 4th at that rpm there isnt enough pull to notice the difference.

[Pig Skill]

Thanks Nedzilla - good to get some feedback

Must admit, its not something that interrupts the driving and one has to purposely try to get it to do it!

Its just how I am, if its something thats wrong, I want it right as quick as possible but if it's a generic 'fault' or a design flaw then I can accept it.

[nottyash]

Mine does it when its cold. Will try it when its warm and let you know.

[Sidewindow]

Do you know if the MAF sensor has ever been cleaned? I think this is done as part of one or both inspection services, but you can also do it yourself if you're careful. I did this a few months ago and it removed all hesitation in all gears across the rev range.

[Pig Skill]

I have whipped out the sensor and visually it looks clean as a whistle. I'll give it a clean all the same though. What is best to clean it with?

Also what does the maf consist of? I can see the resistive wire is there anything else?

[Sidewindow]

I used electrical contact cleaner which you can get from Halfords. I gave the sensor a good spray all over but would suggest you read around this before cleaning (i.e. don't take my word for it)! Plenty of threads on the subject on other forums.

[slimtater]

Am I reading your first post correctly - 2002 car that has only done 2k miles? If so, what service regime has it followed?

[Pig Skill]

Thanks Ill do a bit of searching

Sorry its a typo, its covered 27k miles - will amend now

[slimtater]

Pig Skill said:

Sorry its a typo, its covered 27k miles - will amend now

Thought my 2002 with 30k miles was low! Have you carried out the air intake mod that everyone raves about?

[Pig Skill]

No not done any mods really.

Its a one owner before me and it was a lady so I guess it could do with a good blasting to clear out the carbon.

[scottri]

slimtater said:

Thought my 2002 with 30k miles was low! Have you carried out the air intake mod that everyone raves about?

Whats this mod then?

Mine also has this hesitation at low revs. Its a bit annoying but i think its just the way they are.

[slimtater]

Lots of info here:
http://forums.m3cutters.co.uk/showthread.php?t=393...
Essentially you buy one of these:
http://www.screwfix.com/p/92-5-offset-bend-black-6...
Which then fits perfectly in to the end of the air intake next to the n/s fog light and feeds air in. Cheap and simple and does actually seem to iron out a few of the flat spots from cold / low speed.

[Sidewindow]

Read about this ghetto mod before, am slightly sceptical how it can improve on M division's design! It does appear to have support from Evolve so there must be something in it. Would have thought it would decrease brake cooling on one side, increase drag and decrease the diameter of that intake, let alone look like a piece of guttering in the bumper...

[slimtater]

A few have reported the n/s brake getting a bit warmer after heavy use but you can remove a section behind the duct to aid flow. Not sure it can increase drag as the air is already going in to that area of the car and is merely being directed upwards. It is probably a ghetto mod because it costs £2.99 - perhaps if someone made a custom piece of pipe in carbon, people would happily pay £50? ;-). Maybe BMW didn't go for it in case it looked like a piece of drainpipe? On mine, it doesn't - you can barely see it and it just looks like a fairly normal intake.

Edited by slimtater on Sunday 20th November 18:55

[Sidewindow]

All fair points!

What difference has it made to yours? Better response? Any change to mpg or sound?

[slimtater]

No difference to sound and not really done enough miles to see any change to mpg. It does feel a little smoother though but that may be a placebo effect! For £3, it is just worth a try.

[The Ferret]

It made a a massive difference to the cold running for me. Car no longer hesitates at all when cold, its like a different car.

One thing I would say, if you are doing this mod MAKE SURE YOU ADD SOME KIND OF MESH TO THE PIPE. Especially important at this time of year with all the leaves falling off trees.