[s-cars] taking my turn - resolved
Philip Mische
pmische at comcast.net
Fri Feb 21 15:49:52 EST 2003
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Yes, it was helpful - once again jabbing something with sharp sticks brings=
results- getting the terminals out of the connectors was a bit of a trial.=
And yes the problem was with the POS.
I don't agree with the cut & splice operation however, that should not be n=
ot necessary.
After the offending POS channel is identified you end up with one 3-channel=
POS and one 2-channel POS. The 3- channel one goes on the right (looking =
at the firewall) for cylinders 1, 2, & 3, with the top & bottom harnesses p=
lugged in normally. The 2-channel one goes on the left for cylinders 4 & 5=
. Swap the wires/terminals (if necessary) in the top & bottom harnesses fo=
r the left one to make sure the good 2 channels are now used; the dead one =
will be blank.
http://www.sjmautotechnik.com/S4_Ignition.htm goes through the process step=
by step.
----- Original Message -----
From: Robert Myers
To: Philip Mische
Sent: Friday, February 21, 2003 2:00 PM
Subject: Re: [s-cars] taking my turn
See below. I think the attached write-up will likely answer your questio=
ns.
At 01:57 PM 2/21/2003 -0500, you wrote:
Yes, I've done the sleuthing, found the culprit, swapped the POSes, BUT=
I CAN'T GET THE DARN CONNECTORS APART TO CHANGE THE PINS!
Any ideas?
Tnx,
Phil Mische
----- Original Message -----
From: Robert Myers
To: Philip Mische
Sent: Friday, February 21, 2003 12:05 PM
Subject: Re: [s-cars] taking my turn
At 06:00 PM 2/20/2003 -0500, you wrote:
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Gents,
95.5 S6. Chipped, runs fine. Turn off the car. One hour later I =
fire it up and not everyone fires up - it acts like it's got a fouled plug.=
It's very unhappy, and so am I. We limp home, grateful I don't have to d=
eal with this out on the road with my 4-yr-old in the back seat.
Pulled the sparking plugs out, they all look fine (!). I have 2 qu=
estions (for now):
1) Is this how a bad POS behaves?
It can be. A bad POS channel produces a permanent miss in the effect=
ed channel. You can do some sleuthing and then some rewiring to bypass the=
bad POS channel virtually for free.
2) What's the correct spark plug torque? After all the discussions=
about plugs tearing out of their mounts and denting the hood, after all th=
e discourse RE the importance of torquing them correctly (w/o anti-seize) -=
I can't find the damn torque spec in Bentley. If you want just tell me th=
e page #...
21 ft-lb, IIRC.
TIA
Phil Mische
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Bob
*****
Robert L. Myers 304-574-2372
Rt. 4, Box 57, Fayetteville, WV 25840 USA WV tag Q SHIP
'95 urS6 Cashmere Grey - der Wunderwagen ICQ 22170244
http://www.cob-net.org/church/pvcob.htm
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I've been wondering... Who would Jesus bomb?
Bob
*****
Robert L. Myers 304-574-2372
Rt. 4, Box 57, Fayetteville, WV 25840 USA WV tag Q SHIP
'95 urS6 Cashmere Grey - der Wunderwagen ICQ 22170244
http://www.cob-net.org/church/pvcob.htm
*****
---------------------------------------------------------------------------=
---
urS-car PSO "repair"
Bob Myers <robert at s-cars.org>
Diagnosis: One cylinder missing. Plugs, ignition boot, etc., are all OK=
. The miss happens at all times, idle through WOT. If the miss happens on=
ly when some boost is being developed then the problem is likely to be one =
of the individual cylinder coils rather than the PSO.
This basic technique was suggested by Jeff Hemmerlin.
The Power Stage Output for the urS4/S6 is a three channel device which fe=
eds a signal to the individual coils for each spark plug. Two PSO units ar=
e required. This provides 6 (2x3) channels, of which only 5 are used. Whe=
n one channel goes bad it is possible to disconnect the wires from the faul=
ty channel and move them to the unused channel. Of course, this can be don=
e only once. The second time it happens you are forced to buy a new PSO. =
Perhaps that should be spelled P$O.
Determine which cylinder is not firing properly. Remove the cover over t=
he fuel rail. Let the engine idle. Unplug each injector, one at a time,=
until no difference in idle character is made with the injector either plu=
gged in or unplugged. You will be converting the idle of a five cylinder e=
ngine hitting on only 4 cylinders to a five cylinder engine hitting on only=
three cylinders. This is a quite noticeable difference.
The two PSO units are mounted on the firewall behind and slightly toward =
the passenger side of the car (left hand drive) under the black plastic shi=
eld. They are oriented such that they are upside down with respect to each=
other. Remove the shield and unplug the smaller connectors (three pins ea=
ch). One will have three internal connections and the other will have two =
and an empty spot. That empty spot marks the unused "spare" channel. That=
spare channel is for "cylinder #6". The other two connections of that plu=
g are for #4 & #5. Audi is nice and orderly, they are in numerical order. =
The connector having three connection positions is for cylinders #1 thru #=
3 and they are also in numerical order. The black wires going to the coils=
are numbered clearly with Arabic numerals.
After determining which of these black coil wires is to be moved pull the=
plug containing that wire and peel back the rubber boot covering the wire =
end of the plug. Using a sharp knife blade, gently pry the retaining clip =
holding the inner parts of the plug away from the retaining pin and slip th=
e innards out of the plug. It will come out easily as a smaller (probably =
hot pink color) plug piece. You will see small snap levers which hold the =
individual connectors inside the main unit. Use the "special tool" (consis=
ting of a couple of ~1mm by 10mm flat steel pins which slip into the connec=
tor piece just like it was the mating half of the PSO). This frees the pin=
up so that it will slide out by pulling the wire. The tool is available a=
t fairly reasonable price from Snap-On but could probably be Jerry-rigged f=
rom a thin piece of metal. I borrowed one from a helpful mechanic friend.
Now this operation becomes a cut and splice operation. Cut the wire goin=
g to the "missing" cylinder and crimp on a butt connector. Then crimp in a=
second piece of wire (to lengthen the wire by perhaps 5 inches or so - do =
a trial fit before crimping anything) so that it will reach the spare conne=
ctor to which it will be attached. (You will likely need to slit one of th=
e plastic weather shield cable covers to extract the wire far enough to wor=
k on it. When the job is complete cover the slit with a wrapping of electr=
ician's tape to restore the weather resistance.) I was able to do this so =
that the entire crimped connector is covered by the rubber boot. If you ar=
e lucky and either #4 or #5 is not firing then the cut/splice is not necess=
ary, simply move the wire from one slot to "#6".
Now disconnect the larger 4 pin connectors and examine where "#6" is in r=
elation to the other three pins of that connector. The closest is #5 the n=
ext is #4 and the far one is (I'm assuming) the power lead. It may be some=
thing else but it doesn't matter for our purposes. The other 4 pin connect=
or is numbered similarly. "Power" through #3. Remove the small connector =
for the "missing cylinder" and cut/splice as needed so that it may connect =
with the "#6" space.
Details:
Keep leads reasonably short
Use heat shrink insulation over splices
Where necessary, slip leads through the rubber boots in such a way that e=
verything remains dry.
"Repair" any needed slits in insulating weather covers with electrician's=
tape (or the like).
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