2788Re: [bmw e28] "Stutter"___528i,_Manual,__1985, £126k
- Aug 31, 2004If you find that repairing your transfer pump doesn't solve the problem take
another look at your Air Flow Meter, these are a dreadfully unreliable part
and movement of the internal flap doesn't always indacate that its working
properly. The movement of the flap caused by manifold vacuum in tern moves a
wiper arm housed in the black platic casing on top of the AFM, this arm wipes
over a copper track to then give a reading to the ECU of how much air is
coming in. If this copper track is coroded or dirty then incorrect readings
are sent. And if you are getting your stuttering symptoms at roughly the same
depression of the throttle each time then a certain part of the track could be
worn / dirty.
Many people are of the opinion that the track can be cleaned to improve things
but I wouldn't recommend it, many an AFM have been killed off completely when
Ideally you would put a known good AFM in your car and see if that solves your
If you don't have acess to one then you could buy a new or reconditioned one.
www.gsfcarparts.com specialise in these to some extent but they don't come
cheap. I would bet you won't see any change out of £125 for a recon.
"Steve Austin" <steveaustin1@...> wrote:
> Ron, Thanks once again. I live in England, we don't get 120F
> temeperatures: -120F maybe! The "Vega trick" - I take it is a reference to
> a cheaper part. I'll see if there are any distributors over here, but do
> you have any more details. Eg Make, Model, etc.. Cheers. --Paul. (PS.
> Ordered the diff oil from redline you recommended by the way. Will get that
> changed tomorrow)
> >From: Ron Kall <ronjkall@...>
> >Reply-To: bmwe28@...
> >To: bmwe28@...
> >Subject: Re: [bmw e28] "Stutter"___528i,_Manual,__1985,__£126k_
> >Date: Mon, 30 Aug 2004 16:28:29 -0700 (PDT)
> >It's the transfer pump. Try running up a 4,000 foot
> >mountain at 6% grade and outside temperature at 120F.
> >If it vapor locks before you get all the way to the
> >top, then it's the transfer pump. Do the vega pump
> >trick. It's only $30.00, USD of course. There are
> >instructions online to see the fix. Search yahoo for
> >the pix and detailed instructions.
> >--- bty821185 <steveaustin1@...> wrote:
> > > For the last two years I've had a problem that
> > > doesn't cause me too
> > > many headaches, because of the way I drive and the
> > > relatively few
> > > miles per year I do, but I'd sure like to cure it.
> > > When travelling
> > > at a CONSTANT speed (eg 35mph in 4th, 20mph in 3rd,
> > > etc... but does
> > > not seem to happen after, say, 55/60mph in 5th)I get
> > > what can only be
> > > described as a "stutter" or part surge. The RPM
> > > gauge doesn't move
> > > and I have no hesitation when accelerating or
> > > decelerating. But I get
> > > the feeling that fuel is not getting through
> > > properly. Last week
> > > changed fuel filter again. 6k miles ago: New
> > > fuses, cleaned main
> > > grounds with Detoxit contact cleaner, New Main Fuel
> > > Pump, Fuel Pump
> > > relay, Fuel Filter, Fuel Pressure Regulator, and ran
> > > a bottle of
> > > redlne SI 1 injector and valve cleaner through fuel.
> > > Also, at same
> > > time: new Cap, rotor, leads, plugs, air filter, oil
> > > filter and oil
> > > change. Recently run another bottle of SI-1
> > > injector cleaner
> > > through, and New Oil/filter change, Valve
> > > Adjustment, Air filter,
> > > plugs checked (perfect), Air flow sensor flap
> > > checked for binding
> > > (OK), Wynn's Injector/Carburettor Cleaner sprayed
> > > into
> > > intake/throttle body as per instructions on can.
> > > Can anyone suggest
> > > solution or a list, in priority order, of things
> > > to check. Could
> > > it be Transfer Pump? Partially restricted fuel
> > > lines? Throttle
> > > position switch? ECU? FIO> This car uses the L
> > > Jetronic system, there
> > > is no Oxygen Sensor and no EVAP (charcoal cannister)
> > > control. --
> > > cheers. Paul
> > >
> > >
> >Ron Kall
> >Rancho Cucamonga, CA 91730
> >1986 528e
> >1985 535i
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