88 5KTQ Fuel supply issues

[SJ]

----- Original Message ----- 
From: "jesper moreau" <jesper5ktqm.audi at gmail.com>
Subject: Fwd: 88 5KTQ Fuel supply issues

Problem summary.
ENGINE WILL NOT RUN
Solved problems:
1. spark.... resolved by using proper window on bell housing
2. intake air leak... resolved.... found the throttle body to
intercooler hose aka michilin man lipped out.

Outstanding problems
3. Fuel problem - engine wont start, but will kick over when using ether.

diagnosis to date:
- fuel line disconnected at dist, got flow, but low and with bubbles
**** which fuel line?

I do get tons of pressure coming from the fuel supply line going into the
fuel dist.
**** Fuel line right after the fuel filter? Or before? What is "tons" of
pressure? Got a pressure gauge?

I don't seem to get what looks like any substantial pressure on the top side
of the dist.
**** Top?  The lines going to injectors? Cold start injector? You wont get
any pressure at the injector lines unless you lift up the sensor plate. That
lifts the valve to let fuel flow.
But you always get Pressure at the cold start valve because its connected
directly to system pressure(90 PSI).

I believe the problem is the fuel distributer!!!
**** Maybe. You need to troubleshoot and not shotgun.

I got fuel seeping from around the gasket between the fuel
distributer plate and the airbox...... not normal
**** Thats just a gasket to keep outside air out. If you see a wet spot
there, the fuel is getting there either from the injector lines on top, or
from some internal source.

****Things to Do:
1. Do you have the Bentley manual?
2. Check for fuel output
This is done at the line going back to fuel tank. There is a fuel line
connection for this test just behind the fuel filter.
So much fuel volume, in 30 seconds, when voltage at the pump is 12 volts.
Check the Bentley.
If this fails:
3. Test for fuel pressure from fuel pump before the fuel filter. Should be
over 100 PSI.
4. Test for fuel flow from fuel pump . . .you should get a whole lotta fuel
pouring out.
5. Test for system pressure at the cold start injector. Should be 90 PSI

The fuel system works like this.
Tank--->Pump--->accumulator--->fuel filter---->fuel distributor-->fuel
pressure regulator--->return line to tank

The key item that determines system pressure of 90 PSI is that fuel pressure
regulator at the tail end of the system. Its a mechanical device, spring
operated. When pressure is greater than 90, valve opens and dumps fuel. When
pressure goes under 90, valve shuts and fuel pump builds up pressure.
For the fuel pressure regulator to work right, it needs more than 90 PSI
coming in. The fuel pump has to  provide more than 90 PSI.

A blocked fuel line or filter will prevent fuel flow and you  wont get  the
pressure you need at the fuel Pressure regulator for it to work right.

If you have system pressure of 90PSI, and still no fuel getting to the
injectors, then the problem is confined to the fuel distributor, including
the DPR - differential pressure regulator.

As you can see, we need to test for and check out fuel pressures.
Get a guage or make one up. Denis has kluged something up that seems to
work. If someone can translate and flesh out what he is saying, we will know
how he did it.
I think he just used an air pressure guage(150 PSI), connected to fuel lines
via various combinations of rubber hoses and clamps. Nothing fancy, but it
worked.

SJ
85 Dodge PU, D-250, 318, auto
85 Audi 4k - - sold but still on the road
88 Audi 5kq
90 Audi 100q