E30 low rpm poor throttle response

I'm beginning to suspect all is not quite what it should be with my newly aquired E30 M3.

I had reserved judgement until I got the awful Scorpion exhaust system and Green cone air filter off in case that was clouding things, but now I have put the original BMW airbox back on and a nice quiet new Supersprint exhaust system (with the crucial x-pipe).

The throttle response is very tardy at low rpm, approx the first 2000 rpm. If you blip the throttle in neautral at those engine speeds it bogs before it revs.  At higher rpm it's fine.

I cleaned off all the crud (and there was a lot of it) from the distributor cap and rotor contacts yesterday but no difference. I have a new distributor cap and rotor arm coming this week anyway, and replacement Magnecor HT leads are also on their way.

Any theories what might be causing this issue?  I've not noticed it missing at all, just being very tardy to rev at low rpm.

I had the plugs out last weekend and they looked ok.  If thats how they all are then fair enough, I was just expecting to be able to blip the throttle and the engine respond immediately.
I guess the masters in Zuffenhausen have spoiled me...

_Tim_ wrote: I guess the masters in Zuffenhausen have spoiled me...

Please read the forum guidelines about posting offensive remarks.


Seriously though, without driving your car it is hard to diagnose the fault.. if it is more than just being 'off cam' then you need it sorting. These cars will never have the grunt of a porker but will outshine them in all of the other driving disciplines.

Air flow meters (AFM) can be problematic, but lets get those leads and dizzy bits changed first and then report back.

Zuffenhausen indeed!

Tim.
Bogs down or slow to react.If its slow to react I`m affraid it is a trait of these cars,due to the afm setup.The barn door is very slow to react and that`s the main reason people dump them,a custom remap works wonders and is well worth considering.

Jon

I thinbk if the AFM is a bit tired you may get this. In addition if it's running a tad rich it will also do it. The most noticeable thing after a remap is that they are much brighter at low rpm especially just after start up, where they normally really chug until warmed up. They are by default very rich at start up hencr the chugging and ease with which the plugs can be fouled. A remap will sort all that, but that's once you know all the other bits are healthy.

Might be worth trying swopping over the afm/ airbox
with a know working example. Otherwise it could be
that it needs setting up properly. i.e. setting base
idle, synching the throttle bodies, setting the CO, etc

Also worth checking for air leaks around the seal on
the afm if you have just re-fitted it + the usual
suspects.

worth a read:
(u will have to paste manually as 'LINK' dosent work
for me, sorry)
http://member.rivernet.com.au/btaylor/BMWText/techn
ical/AirflowMeterCalibrat.html

Edited by 215DMX

Mine used to chug before it was remapped, now it's much better.

Roops

If the spring becomes a bit worn some people fiddle around with the pre-tension of the spring(under the black plastic cover) but I've been told to keep hands away if you don't know for sure what you'r doing.

Best option is still to delete the AFM. I have spend a fortune for a new 2.5 engine with hot cams and still drive around with an 17 year old AFM. That can't be the best solution.....

Edited by UweM3

Well if it is the AFM mine is coming off my car as we speak so i am sure you could persuade me to part with it for a small donation...

Speak to Bexleys in Kent if I were you, get the car remapped and if it is the AFM they can shove mine on there and then

Tom H