FW: Ignition Switch Failure Mode

kneale at knitknacks.com kneale at knitknacks.com
Fri Jun 19 07:24:52 PDT 2009

Do you know that you have no spark or fuel while cranking?  If so, I'd
suspect the ignition and engine speed sensors.  They have to be providing
the ECU a signal in order for it to activate the fuel pump relay and
sparking system.  Those things are twenty years old now.  They fail
commonly much sooner on V8s because they're located near the driver side
exhaust plumbing on V8s.  On 10valve cars they escape that heat issue, but
they're still subject to age.

Bentley has test specs.  Connectors are on the firewall behind the valve

Original Message:
From: Geraint Lloyd geraintlloyd_qc at yahoo.ca
Date: Fri, 19 Jun 2009 09:59:02 -0400
To: quattro at audifans.com, 200q20v at audifans.com
Subject: FW: Ignition Switch Failure Mode


I have an intermittent hard start issue with the 1989 - 200 TQA - MC2
I had a similar issue a couple of years ago and replaced many, many, many,
many parts then and the problem went away. Unfortunately I replaced too many
parts at once and am not 100% sure what the cure was. 

Essentially the car is hard to start if it has been left for a while,
including overnight.
It cranks, but either doesn't fire at all or gives an occasional hint of
As it's Mrs L's car and she can only get it to start 75% of the time, then
the situation is clearly NOT COOL!

As per the title, I was wondering what the failure mode of the electrical
part of the ignition switch was?

Are they known to fail such that the motor will crank but there is no spark
or fuel? 

I would prefer to keep any answers to this issue restricted to the one
question at the moment, if you guys don't mind. I will post again regarding
other crazy theories that i might have later on.....


Some background for this time:
No codes listed
I have been over most of the stuff on SJM's troubleshooting list

New over the last 24 months = ecu temp sensor, fuel pump relay, CSV wiring,
2nd knock sensor, ISV, fuel filter, check valve, throttle pos switch, plugs,
dizzy cap, rotor arm,  HT leads, lambda probe. Reset mixture with my bosch
CO2 meter, 

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