tools for 4ks fuel sys work

[quk@isham-research.demon.co.uk (Phil Payne)]

In message <9710311553.AA28472@mostro.sps.mot.com> roger@mostro.sps.mot.com (Roger Albert) writes:

> Ok, so, I'm getting ready to really dig into my 86 4ks' fuel sys problems,
> which I've previously babbled about on this list.  In the spirit of hating
> to get into a job and have things all torn down only to find out I don't
> have the correct tools, what's a good basic list of tools to work on this
> sys.

(Heh, heh.)
 
First off - a fuel pressure gauge.  I got a 'Star Hoffman' gauge from JC 
Whitney (stock # 12NR3617U) for $54.95.  Second - a portable CO meter.  Third - 
a DMM with 5-cylinder RPM and duty cycle readouts.  A second meter is useful 
for things like idle stabiliser setting - looking for 800 rpm at 430ma, for 
instance.

The fittings on Audi fuel injection are mostly flare nuts, but I found that 
special flare nut wrenches aren't all that useful.  I have 12mm, 14mm and 17mm 
deep 12-point Crowfoot flare nut sockets, which are to die for if you do a lot 
of this work.  Get Stahlwille rather than Snap-On, because Stahlwille are 
1/4" drive and _MUCH_ more manoeuverable in the tight confines of the top 
of a metering head.  Most of the nuts are brass rather than steel, so getting a 
good purchase before applying torque is essential. I've found that most of the 
'in-line' connections are best tackled with high-quality (I use Bahco) 
adjustable wrenches. Something with thick jaws.
 
Don't forget a cloth (an old towel is best) to wrap around the first joint you 
open - you'll have to catch an ounce or two of fuel.  Pre-order some 
replacement copper washers (Audi calls them gaskets) and expect to have to 
replace every one - two on most fittings.  There are three different sizes on 
most Audi systems.
 
Some of the head fittings are banto/banjo bolts with 6mm and 10mm Allen heads.  
I recommend _against_ the 'ball end' type of Allen driver, as they tend to cut 
into the relatively soft metal and can wind up captive in the damn bolt when 
you finally get it off.  BTDT - NDIA.  Depending on the geography of your 
engine compartment, you may have to shorten Allen wrenches. You may find 
'undoing torque' _VERY_ high on some components, and a robust pair of grips 
with soft jaws can be handy for applying opposing torque so you don't just rip 
the whole thing out.

If you start _serious_ messing about, you'll need a linear caliper (needn't be 
amazingly high quality - 0.05mm precision is fine, and accuracy unimportant) 
and a depth gauge with a fairly wide base - 60mm is terrific.  The caliper is 
for measuring the protrusion of the plunger from the bottom of the metering 
head, and transfering the value to any replacement head or the same one after 
you've R&Red the plunger.  The depth gauge is for measuring the depth below the 
metering head base of the roller moved around by the air mass sensor paddle, 
and for measuring the position of the paddle itself.  Accuracy is important, 
because you have to match Audi's settings.  You should really have a feeler 
gauge to check that the paddle isn't fouling the funnel, but a piece of paper 
will do as well.

Coathanger wire is useful here, too.  I have a set of hooks made up with some 
small diameter rubber hose slipped on one end - you can hook them into the 
underside of the bonnet (hood) and use them to hold fuel lines, etc., out of 
the way.

Most important item of all - Charles Probst's book on Bosch Fuel Injection, 
published by Robert Bentley.

-- 
 Phil Payne
 Committee Member, UK Audi [ur-]quattro Owners Club