RE: 89 320i Intermittent Missing

[Ciaran Moynihan <ciaran.moynihan@xxxxxxxxxxxxxxxx>]

Fuel Filter is new, Fuel pump wiring and connections seem fine. How do I
know if the
pressure regulator is ok - As far as I can tell it is bu the what do I check
?

As far as things Electrica go - this is a RHD car so I assume you mean the
drivers side in this 
case - At least thats where the ECU is - Under the Steering column ;-) .
Anyway - I have ordered the
Bently manual, All I have been using up to this is the Haynes manual which
is not great. Incidently 
does the manual cover the 89 320i as I dont believe that this car was ever
sold in the US. Its an E30 
with six cylinder 12 valve 2.0L M20 engine and from what I can gather from
various Web sites it wasn't 
available in the US or if it was nobody bought them! In any case I am hoping
that the Motronic system 
on my car should be very similar if not Identicle to the 323 and 325i of th
same vintae and that I should
be able to gt the info I need from this.

I have found a Website that lists fault codes for the Ljetronic and Motronic
ECU along with some tricks for
displaying them via a sequence of pulses from the Check Engine light
(http://www.eskimo.com/~dalus/bmw/repair_faqs/motronic.html). Thse are
accessed by sending an instruction to the ECU by depressing
accelerator pedal a number of times (and presumably operating the TPS) with
the Ignition on but the 
engine stopped. This is all good and well however my car doesnt have a
'check Engine' light as such instead
it as a 'check' light which operates in conjunction with an info panel of
LEDs above the Rear view mirror
which tells me if my stop light are faulty etc. I have been unable to use
this method described at the above site
to gain access to these fault codes I suspect that this is because when I
turn on the ignition in my car the check
light flashes until I depress the brake pedal allowing the system to check
the stop lights. If anyone out there 
has any tips on getting access to these please let me know.

In answer to your question re trying to Isolate the circumstances - I have
tried and failed here  I can happen at 
any time in any situation however it does seem to be more common when
cruising at a constant speed on a motorway 
and it seems also to be more common in hot weather ( engine temperature is
always either normal or just warming 
up - It never goes above normal ) BTW hot weather in Ireland is cool by many
other standards at 24-27 degrees 
C Max ;-).

I dont know if I have a TDC sensor on the flywheel - I will have a look -
the car has manual Transmission though. 
I do have a  sensor on the crankshaft pulley although I believe that this is
not used by the ECU and is only used for diagnostic purposes as the wiring
from this sensor seems to go as far as the engine diagnostic socket and no
further.

I am also going to check the wiring to the Ignition coil as per Paul de
Jong's suggestion on the digest as well 
as trying to fugure out why my posting had those annoying =20 instead of
newline characters - sorry about that!

Suggestions greatly appreciatd though keep them coming if there are any more
available

many thanks

Ciaran

- -----Original Message-----
From: Sammy A. Haroon [mailto:sah@domain.elided]
Sent: 20 August 1999 14:39
To: bmw-digest@domain.elided; ciaran.moynihan@domain.elided
Subject: Re: 89 320i Intermittent Missing


Hi,

First of, per Michel Potheau, back to the basics:  Check the fuel filter,
fuel
pump, fuel pressure regulator, rotted line, loose or corroded electrical
connection, etc.  Then on to the electrical things.  You can basically sit
in
the passenger seat and check currents and resistences on just about
everything
in the car by unplugging the computer terminal and using the correct pins. 
Ofcorse you will need a good tech/info source like a Bentley, shop manual or
Helms, etc.  Also, I dont have the site handy which contains all the error
codes from the computer but I do have a copy at home.  I will scan it in and
send it to you.

I had a similar problem on a car I was working on.  It was a 87 325is.
After
just about testing everything, the problem ended up being the ETA fuel
injectors.  The last shop installed the incorrect injectors in the car.  The
easiest way you can find that out is by measuring the resistence across FI
terminals and checking them against the correct ones you ought to be using.

Other tricks are for fuel related testing, per Brett Anderson, which works
very well too, if you have tested just about everything else:
Install a pressure gauge in line with the fuel supply to the FI rail and tie
the gauge to the wiper.  Make sure you disconnect the wiper fuse.  That will
tell you if there is a pressure related problem when the car cuts off.

Another interesting one, per Mike Miller, is where couple of teeth on the
fly
wheel can get chewed off by an old started.  Then, if you have the TDC pick
up
sensor on the tran bell housing, it can give incorrect info to the computer.

I would recommend pin pointing some exact circumstances to the "lurch".  For
example, does it only happens when below 3500 RPM?  For that try driving the
car on a highway at a consistent speed w/o changing gears.  Does it happens
when its really hot?  (Some fuel line heating up causing vapor)  Once you
can
do that, I would be able to help out more.

Good luck.

> I'm new to the list and was wondering if any of you have come across a
very
> strange very intermittent problem that I've been having with my 1989 320i.
> 
> Occasionally while cruising or accelerating the engine will die for a
second
> and then pick up again. This results in a very annoying 'lurch' in the
car.
> There is no spluttering or fading power loss associated with this, the
> engine just seems to shut of for a second and then pick up again. This may
> happen 4 or five times during one long trip and then might not happen
again
> for weeks.0
> 
> Once or twice the engine has just died for no reason at a steady tick over
> and started easily again. The car can also take a long time to start very
> occasionally and sometimes I have had to leave it for a few minutes before
> it would start. There is however no strong smell of fuel which I would
> associate with 'flooding' when the engine is hot. The Tick over is
normally
> a little rough but steady.
> 
> I have checked all Wiring to the ECU, Engine sensors, Fuel Pump and Relay
> and all seem OK. Otherwise everything else is fine with the Car.
> 
> Has anyone come across a problem like this. I am considering paying a
Bosch
> Engine Management specialist lots of 3=A3=A3 to run a full set of =
> tests on the
> car but as it is an intermittent problem they will not guarantee me that
> they will find it.
> 
> The Motronic ECU is supposed to store fault codes. Is there any way to
> download and analyse these without specialist equipment or is there any
> other way to diagnose this problem.
> 
> I would appreciate any suggestions anyone might have on this either via
the
> digest or direct email.

- -- 
Sammy A. Haroon,  Taxila, Inc.,  770.234.9087
mailto:SAH@domain.elided
http://sah.home.mindspring.com/
- --
"Once spirit was God, then it became man, and now it is even becoming mob."
Thus Spoke Zarathustra, part 1, "Of Reading and Writing" (1883)

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