440 Idle Problem

Problem with my 95 440 1.8 Si... again.

Lack of power when first accelerating (both from standstill and when already
moving). It's almost as if something is sticking or restricting the fuel
flow. Suddenly it pulls forward swiftly, back to normal power and quite
quick.

Then, when I depress the clutch, one of two things usually happens: (1) revs
drop quickly to about 600 and the car feels like it's about to stall before
recovering to about 1000 revs again. (2) Revs stay put for a few seconds at
about 2000 (or whatever speed the engine was at) before slowly dropping to
1000.

Any ideas? Suspect it could be one of a number of things: stepper motor,
catalytic converter, exhaust problem? Had the stepper replaced last summer
so would be annoyed if it were that. Would appreciate any advice.

Regards etc,
Richard Carter

========================
richard at rjcarter dot net

 

Or might I just be lucky enough to fix the problem by getting a fuel
additive to clean the fuel injectors? The STP website seems to think it's
products would do the trick.

Regards etc,
Richard Carter

========================
richard at rjcarter dot net

 

Hi Richard
i'm not a mechanic but will describe the best i can
in layman terms what cost me £350 to find out and
nought to fix,
At the rear of the engine is two thin pipes which are
vacum pipes,the lower of the two leads to a vacum senser
which is fixed in the engine campartment as near the driver
as practically possible,clean this pipe at the engine end
and maybe this will fix you problem.

Hope this helps
Mark

 

Mark, thanks. Had a look yesterday evening but couldn't locate the two
pipes - I presume they're visible from the top of the engine bay rather than
crawling underneath the car? Is yours a similar-aged injection model?

Bear in mind that I'm an accountant so don't mix too well with engine
things...!!!

Regards etc,
Richard Carter

========================
richard at rjcarter dot net

 

Hi Richard
I have a 94 440 Li

Looking at the engine if you look in line to the second spark plug
from the left to the rear of the engine are 4 L shaped thin metal
things (two go left two go right)protruding out of the engine,
which connect to thin black plastic pipes,try cleaning the one that
goes to the air pressure sensor which on mine is the bottom left
hand pipe.
hope this helps
Mark

 

Thanks Mark - found the pipe no trouble and gave it a good clean. It seems
to have helped a bit, the revs don't drop suddenly when declutching any
more. Idle is still fluctuating though: suspect stepper motor as well as the
dirty pipes. Already had it replaced once and evidence of the same on my
other 440 so wonder if it's a common problem.

Many thanks for your help,
Richard

========================
richard at rjcarter dot net

 

Hi Richard
i apologize for my ignorance,but what is a stepper motor
and where would i find one.

Mark