Re: ur-quattro misfire?

[harrison <harrison@indigo.ie>]

Phil Payne wrote:
> 
> I can afford to take the quattro off the road for a week or two - I
> think I'll try my hand at renovating the metering head myself.
> 

Phil,
A word of caution here....
Very little ever goes wrong with the metering head itself. Very simple
in operation. There are really only two things you can check and they
are a) the pressure regulating plunger and b) The pressures to the
injectors are equal and the right spec.

To check the plunger.....
Make sure there is pressure in the fuel system i.e. not more than 30 or
so mins. since the engine was running. Lift off the 'dome' on the air
filter housing, and grip the bolt in the centre of the air flow sensor
disc with a pliers (gently). Try raising the disc......there should be
some resistance through it's full lift but almost no resistance letting
it back down. The movement should be smooth throughout. If there is any
roughness or if it doesn't move at all, the plunger is dodgy.

The pressure to the injectors.....
Unscrew injector line from metering head and fit pressure gauge.
Energise fuel pump by bridging terminals at relay (with ign. switched
on, engine not running) and while pump runs take reading from gauge.
Compare all five pressures and if any need adjustment, under the small
screw cap beside each injector port there is an adj. screw.

Two things to remember.....First, this is CIS, fuel flows thru all five
injectors once the pump is running, so while your checking the pressure
on one, fuel will flow from the other four. Second, you will need to
replace ALL the little brass washers you remove. I tried to re-use but
not very successful.

When I had a fuel prob. with my ur-q I tried a repair on the metering
head myself. I could not get any spares, and when I opened it, surprise
surprise, theres bugger all in there except two large, very delicate
metal washers same shape and size as the head itself,  with a pin-hole
for each injector port. I'm told these vibrate rapidly and pump the fuel
out to the injectors. Sod all else in there so I can't really reccommend
opening it up. In my view, surgery on these is a non-runner. Once
opened, it's shagged! No way will it seal again properly. I ended up
buying a factory (whatever that means) reconditioned one from Dialynx.
Fully guaranteed and worked perfectly for me. 240 pounds exchange.


Just my twopence worth.

George Harrison,
County Kildare,
Ireland.

'85 ur-q
'86 80 Sport