Audi 5000 Diesel conversion

Charlie Smith charlie at
Fri Sep 23 02:50:50 EDT 2005

Earlier, harchris wrote:
> Hi Listers:
> I have 3 '85-'87 Audi 5000 CD TQ's. I would like to put a diesel in one of
> them. There is an '86 Audi 5000 S  Turbo Diesel in a local yard. The engine is
> complete and cheap. I know it won't win any 1/4 mile drags, but we all drive
> too fast anyway.
> Can anyone confirm the following: ?
> 1) I have been told that you don't need a computer for the diesel.
> 2) Motor mounts etc. are the same, simply bolt in.
> 3) The manual transmission from the gas TQ bolts to the diesel.

Right, no computer.
Motor mounts are the same.
The transmission will bolt to the engine.  
  You need to make sure flywheel and clutch parts fit.  Not a big deal.

The diesel engine comes with an injection pump, that as someone else said 
is belt driven off the back of the engine.  The injection pump sucks
fuel from the tank through a diesel fuel filter, and has a return line
that runs back to the tank.  Get rid of the gas fuel pump in the tank.

You will have to rig up a glow plug circuit, VW/Bosch has a timer relay
and you want to use the later fast glow plugs.  Make sure you put a VW
type 50A fusible link in the glow plug circuit.

The hot wire from the ignition just activates a fuel shutoff solenoid
on the injection pump.  This web page has information on the injection

The Audi uses a 5 cylinder version of the 4 cylinder pump used by
VW diesels.  This web page covers how to adjust the pump to increase
power.  Which won't hurt economy if you keep your foot out of it.

I'd thought of doing this conversion when the 5kCSTQ engine wore out,
but I finally sold the car with 200K+ miles on the odo and it was still
working fine.  And then bought a later S6  :-)

I think gear ratios will be fine, since the diesel will rev to 4000 rpm
and more.

    - Charlie

  Charlie Smith  charlie {at}  614-421-1418          Columbus Ohio   USA         photos & technical info

  95 S6 Quattro  -  24 PSI, RS2 6 speed, and other features  
  97 Dodge Ram   -  40 PSI, 4x4 w/Cummins turbo diesel

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