Honda Prelude problems F.Y.I

[Woodd, Michael]

Hi all,

Thanks to all (bar two, you know who you are)
for the astounding number of replies to my last post,
not too many Honda drivers out there eh?!!   ;-)

Anyhoo, found a major cause of some of my problems -
in trying to locate the window washer hose which has
fallen off (DAMN those honda engineers) I had my
wife in the hot seat - I tell her to pull the washer lever, and
she turns the key and starts the thing.... I yell turn it off!!
and she does so, and I hear a sucking noise which
lingers for a second after the engine stops turning.
Frustration forgotten, I get her to repeat, and follow the
noise to........

A largish brass screw with an O-Ring on it, sitting
completely wound out of its hole in the throttle body.
Ah ha!! I say.  Whats that, my wife says, and I flick the
screw up and over the intake clamp, which is *just*
stopping the screw from falling out and away into
oblivion, and into my hand, and show it to her. I've had this
problem for about 6 weeks!!!

Tried to screw it back in, but it wouldn't go, I inspect closer
and see that it has been clogged up with CARBON of all
things, not something I'd expect to find on this side of
the works....  Any ideas anyone?

I have discovered that it must be the idle air bypass screw,
when it is turned in, the idle drops (god i'm good)
It was sucking tons of air in, upsetting god knows what.
 Also, I think it must
be a MAP F.I. system, no evidence of what I
imagine a FLAP AFM looks like, but heaps of important
looking little hoses.  Where does a FLAP AFM
usually live? (i.e. manifold side or before T.B.?)

Took it for an Italian tuneup this w/end, 190 km/h with
much more ease.  Still that speed limiter, come through
for me guys....

Any ideas why virtually all power and torque is found
during the first 1/3 accelerator travel?  Will a new
or reprogammed chip improve things?

Enough for now, stay tuned for the next episode,
where I delve further into the labyrinthine depths
of the Honda Prelude PGM-FI engine bay insearch of
the holy grail (the computer)...

Mike Woodd
(wooddm at akcity.govt.nz)