'91 200 20V TQ Dies on Freeway - Now Won't Start

[Ben Swann]

I second Claus's recommendation - too many errors, yet ECU still reading codes, so not
completely dead.  Some of the errors may be old/uncleared errors.  Could even be the
main ground connection to the engine mount just below the IM and two ground that claus
suggested - that is a single point of failure.  Ben

[Date: Sun, 14 Dec 2008 09:41:15 +0100
From: "Claus Vegener" <vegener at post7.tele.dk>
Subject: Re: '91 200 20V TQ Dies on Freeway - Now Won't Start
To: "Michael Palatas" <mpalat at gmail.com>,	<200q20v at audifans.com>
Message-ID: <8E62263E2D504558A6968A15D0021497 at cvz60m>
Content-Type: text/plain; format=flowed; charset="iso-8859-1";
	reply-type=original

So many errors at the same time - guess a ground connection.
Check the 2 ones at the IM
Claus]

[Date: Sat, 13 Dec 2008 16:49:30 -0800
From: "Michael Palatas" <mpalat at gmail.com>
Subject: '91 200 20V TQ Dies on Freeway - Now Won't Start
To: 200q20v at audifans.com
Message-ID:
	<aa916e720812131649s1cc05c4cmce373ff141f7350c at mail.gmail.com>
Content-Type: text/plain; charset=ISO-8859-1

It was a dark and stormy night....  My "4 month owned", IA Stage III chipped, '91 200
20V TQ was running fine on the freeway at 70mph yesterday when it started to shudder a
bit and lose speed.  Pressed harder on the accelerator - no response.  Had some slight,
unusual vibration you could feel in the steering wheel - almost like the engine
misfiring - as it coasted down to a stop.  Electrical indications normal.  Wouldn't
restart.
Checked the fuel pump fuse - OK - so flatbed towed it home ($130).

Tried to restart.  Strong crank, but rough/unusual vibration as the engine turned.
Checked the following:

Fuel Pump Relay OK
12V at fuel pump connector
Fuel pump running during crank.
Pressure/fuel at fuel filter outlet
Distributor turns when cranked (but did find the wide tipped rotor - will replace
soonest).
Good spark on high tension wire.

Hooked up VAGCOM, cranked for about 5 seconds, and had the following code readouts (and
only these):

"00519 - IM Pressure Sensor (G71)
            06-00  :  Signal too high
___________________________________
00523 - Intake Air Temperature Sensor (G42)
           30-10  :  Open or Short to Plus / Intermittent
___________________________________
65535 - Internal Control Module Memory Error
            00-00
___________________________________
00537 - Lambda (Oxygen Sensor) Regulation
            08-10  :  Control Limit Surpassed / Intermittent
___________________________________
00525 - Oxygen Sensor (G39)
            29-00  :  Short to ground
___________________________________
00513 - Engine Speed Sensor (G28)
            27-10  :  Implausible Signal / Intermittent

Readiness:  N/A"

Any ideas/suggestions?  None of the codes sound too ominous to me, but I am not a code
expert.  Not sure why I would have the Oxygen Sensor faults - just put in a new one
about 2 months ago - car ran fine after that replacement till now.

Mike in North Hollywood, CA]