2000 Audi S4 HFS-3 not spraying ::CORRODED PUMP::

[RusS4!]

Just as title says im having problems with my HFS-3 system not spraying. It was spraying before but for some reason has stopped working. I am pretty sure its wired correctly because as I stated it was working correctly before. When I turn the ignition key to on position the yellow water light comes on for a few seconds then the red w.injection light comes on and the gauge fully lights up. When I start the car the flashing light in the controller box flashes like it should. I have also tried re-priming the system. Any help is greatly appreciated.

[Richard L]

Can you check the following:

1. Remove the 6mm hose from the FAV. Manual trigger the system. Tell me if water is gushing out at a good rate.

2. Reconnect the 6mm hose to the FAV.

3. Remove the 4mm hose from the FAV. Manual trigger the system. Tell me if water is gushing out at a good rate.

[RusS4!]

Removed the 6mm hose and manual triggered the system and water is not coming out like it did before.

[Richard L]

Good find.

Next step check:

4. The pump is running under manual test linked.
5. If there is no pump activation
6. Check the fuse between the 15A relay and pump.
7. Check if there is 12V across the thin red and blue wire under the relay.
8. If there is 12V present and the pump is not running, bridge the two thick red wires.
9. If the pump comes on, you have a faulty relay
10 If the pump still does not come on after bridge the two thick red wires
11. Check if there is 12V across the two-pin connector to the pump.
12. Check the black wire is grounded properly.

That is all for now.

[RusS4!]

I am not getting 12V across the thin red and blue wire under the relay. That was assuming i needed to put one lead on the red and one lead on the blue?

[Richard L]

Yes, one probe on each colour.

You need to link the TST to see the 12V

Richard

[RusS4!]

What do I need to link to TST to see the 12V?

[RusS4!]

I dont see anything that says TST on the control board

[RusS4!]

Ok, in the manual trigger/test mode i am getting just under 12V(11.64). The battery has over 12V

[Richard L]

It is OK to see 11.64.

Please continue with the following tests:

8. If there is 12V present and the pump is not running, bridge the two thick red wires.
9. If the pump comes on, you have a faulty relay
10 If the pump still does not come on after bridge the two thick red wires
11. Check if there is 12V across the two-pin connector to the pump.
12. Check the black wire is grounded properly.

[RusS4!]

Ok I tried bridgeing the two wires and nothing happens and I have 12V going to the pump. It is also grounded correctly.

[Richard L]

It appears the pump is not working. Can you tell me where the pump is mounted?

[RusS4!]

Yes, the pump is mounted to the crossbar where the stock sidemount intercooler use to be.

[RusS4!]

Is there anything I can do? I haven't had this system but a year? Or am I going to have to spend another $210 every year for a new pump?

[Richard L]

It appears the problem is pointing towards the water pump. The pump is not water proof.

The HFS-3 pump is designed to be trunk mounted. It is possible to mount it in the engine bay if the following precaution is taken:

1. The main source of water ingress is the cable gland at the back of the pump. Depending on how the cable is routed, water will run along the cable and end up inside the pump. A generous smudge of silicon sealant will minimize this from happening.

2. Put the pump head on top so water can only trickle downwards, away from the pump internals.

3. Water proof the pump relay assembly by put the entire assembly into a seal box. None of this assembly is designed to withstand the harsh external environment.

Was there any reason why you did not install the pump in the truck as illustrated in the user manual?

Before we jump to any conclusion, can you remove the pump from the car, disassemble it and post a few pictures here.

I have seen pumps failed in less than two weeks when installed externally.

[RusS4!]

Your right Richard, I mounted the pump in the engine bay not realizing the water pump is not water proof. I have also seen others mount their pumps of other brands in the engine bay without problems. I dont know how to take the pump apart. Do you have any instructions? Is there any way to get the pump rebuilt or do I have to buy a new pump?

[Richard L]

You need to undo five screws on the pump head and pull. That is all.

If the motor bearing is corroded, you need a new pump. I have listed all the preventative measure above to minimize this from happening in the future.

[RusS4!]

Hey Richard, Which 5 screws are you refering to? I unscrewd the 7 screws and all I see is a rubber shield that does not want to come off.
Thanks for listing the preventative measures for minimizing water problems but I am now just try to decide if it would be better to buy a new pump for $210.00+shipping or buy a different type of pump.

[Richard L]

Pull harder. It will come off. You need to cut back part of the label to expose the seam.

Until you disassembled it, don't buy a pump yet.