Fw: cold start weirdness

[Huw Powell]

> Three of us have similar problem - temp no start when cold, or after 10 min
> warmup.
> What do you think of the [CSV] switch idea?

Sounds like a waste of energy to me.  It is as much trouble as 
diagnosing the CSV system and fixing it if it is not working right, and 
of course, it doesn't fix anything, it's just a hack, really.

I don't mind having a manual choke on my '73 F250 beast.  I wouldn't 
want one on a fuel injected Audi.

Troubleshooting the CSV system is pretty simple, really, since there are 
only one or two parts.

To find out if it is being fired, put a meter on it before a cold start 
and watch the meter.  Or low wattage light bulb.

If it is, check its function.  One cheesy, easy way is with the engine 
warm and running, give it voltage (via a spare connector and some jumper 
wires, use a fuse to be safe).  This should make the engine run richer, 
which will be compensated for by the ECU.  You might be able to hear the 
difference, or you could probably observe it by measuring OXS voltage, 
or easily observe it by measuring control pressure actuator current 
while turning it on and off.

On my 90 I am also highly suspicious of air leaks, say around the ISV 
hose ends.  I just replaced a flaky IM top half bolt in case there was a 
small leak there.

When it's very cold, a small air leak could make the engine too lean to 
start.  Especially if it is a bigger leak when very cold.

-- 
Huw Powell

http://www.humanspeakers.com/audi

http://www.humanthoughts.org/