Stumbling at high boost

[SIMON HOLTBY]

I was driving in my car today and pulled out to overtake a car in a manner
which other Ur owners will be familiar with ie you are passed and fadeing
into the horizon before the other driver can blink. Anyway this time as I
was along side  with my foot to the floor and at full boost  my car
hesitated and I had to back off.
The last time this happened I traced the problem to the spark plugs which
I had not checked for some time and the gap was too large. The high boost
was putting the spark out. I checked the plugs and they were OK so for
some reason I decided to check the air intake temp sensor and found the
connecting wires had crimps on them and looked in a bad way. I
disconnected them and out of interest went for a test drive and found at
low boost the car was backfireing/pinking etc. 
After cutting about half an inch of cable off I tried to solder the wires
on but old copper cable does not solder well. I decided to try using
Jenolite rust eater which is a type of acid normally used on bodywork and
I found that the copper became quite shiney and it was the best fluxing
agent I have ever used. The temperature sensor is an item which Audi have
thought of a daft price and quattro'd it, about 120 gbp so I did not want
to get it too hot. But not much heat was required to get the solder to
run.
The resistance of this sensor is low, around 25 ohms so good connections
are critical for accurate ignition timeing.
Anyway went for a drive again and the problem was solved.
Sorry for going on but this may help someone with a similar problem.

Simon Holtby
'84 Urq




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