re: hyperactive Idle Control Valves _And E36 spark plugs

[jkerouac@xxxxxxxxxxxxx]

re: hyperactive Idle Control Valves _And E36 spark plugs
This is another nonstandard innovative simple ways to take care of
common nagging mechanical problems on our BMWs.  So if you're a purist
who doesn't believe it if the ETK doesn't list an overpriced part to
unnecessarily replace, please skip on to the next article.

For the rest of us,
Here's how I've regulated hyperactive Idle Control Valves since BMW
introduced them,
_and how a spark plug change led me to discover that it even fakes out
the adaptive systems in OBDII.

     I've had a quick fix for ICVs since they first came out in the
eighties.  The problem is that they let through too much air when they
get hyper.  So what if you could restrict the amount of air they pass to
the engine so that it still gets enough air to run at normal idle for a
warm engine, but not so much that when the valve opens full the idle
speed get out of control when the engine is cold?
A further danger of this cold engine idle speed lungeing, is that on
first ignition of the engine, there is no oil pressure yet.  So if the
cold engine lunges up to 1400 as my //M3 did, or others get 2500 rpm
which usually means a fully open ICV, you also can get a split second of
very unhappy sounding bearing clatter until the oil pressure comes up.
     The answer to my previous rhetorical question is, of course, yes,
or I wouldn't be making this posting.  And its fairly simple to do.
     To restrict the maximum amount of air that can pass through the
ICV, simply plug the hose with a washer.  Either a 1/2 inch or 3/8 will
be the size, depending on model.
     On the E30 4 and 6 cyls. I wrapped the wather in electrical tape
before either pressing it into the hose or taping it onto the inlet of
the valve.  This of course will cause the engine to stall since _no air
will get through.  So poke a bunch of holes in the tape with a thick
sewing needle.  This will let you calibrate the valve to just the amount
of air the engine needs for the cold idle speed you desire.
     On E36 OBD I and II, likely no need to tape the washer, the smaller
hole in the middle of the washer will likely be small enough.  When I
first put the washer in my //M3, the engine stalled on first start.
Second try it almost caught an idle before also stalling.  After a few
attempted starts it grabbed a very low idle, then the miracle of
adaptive motronics took over.  The ECU got with the program, literally.
It brough the engine up to a stable cold idle of about 800rpm rather
than the hyperactive bearing clattering instant lunge to 1400rpm or the
pre-hyperactivity cold idle gradual buildup of about 1000rpm.
     Then with the engine warm it idles at 6-700rpm.

How did spark plugs fit into this?
     On the E36 //M3 with factory plugs, the cold idle built gradually
over a few seconds after starting up to about 1000rpm.  A few tuning
changes had a side effect of the cold idle sometimes exceeding 1100rpm
though the warm idle still held 5-600, a firm 650-700 with the AC
switched on.
     The big change was switching to the Bosch Platinum plugs, the four
contact style.  Superior to the OEM plug, and I found the car did run a
tick faster 60 to 80mph on the stopwatch too.  Beside being 2/3 the cost
of the OEM plug.
     With the platinums, they seem to have a superior cold running
performance.  So on first ignition, the engine lunged to that 1400 on
first ignition before the oil pressure could circulate.
Also, they settle in at a warm idle of about 100rpm faster than the OEM
plug.
     Why is the OEM spark plug what it is rather than BMW using the
superior performing platinum plug?
Marketing, and Durability.  BMW specs a 30k mile replacement cycle for
the OEM spark plug.  Hogwash.  Efficiency actually drops off by 15 k
miles, and some 30k mile plugs I've seen are just plain butt ugly.  But
the OEM plug will keep a car passing emissions for 30k miles, and the
Platinum plug probably would not.  Also, with free service included in
the warranty, BMW will get away with not paying the costs of changing
spark plugs in a lot of cars that don't reach the Inspection I or II
service indicator light before the free service period is exceeded.
The Bosch Platinum plug in my experience with four sets of them now is
that by 10k miles they show obvious wear, and 12k miles a decrease in
economy is noticeable..
     So its Bosch Platinum 4417 Spark Plugs and a washer in the inlet
side of a hyperactive ICV to regulate the idle.  If its a choice between
a five cent washer and a $100. valve, I would at least try the washer
first.
Good Luck,
'jk

------------------------------