speedyto

Hello, I am trying to troubleshoot the after run pump and I can’t find accurate data online or the manual, I don’t know maybe because is 2001 ?? and they changed lots of things after 2001 forgetting about 2001 models 😊.
Maybe somebody can help me and clear the fog
1. The after run pump is tied to fan control module ?
2. Manual shows a relay and a fuse ( in 2001 doesn’t exist )
3. I installed new Bosch pump (ECS tuning) and JHM cooler sensor
Pump is not running ( with the new pump I got new connector and terminals, the Bosch pump has different polarity ?? the OEM plug plugged into the Bosch pump...off course no installation instructions with the pump or online available )
Thank you 😊

cu52

Pump plumbing changed in 2002/03 but the operations remain the same. Have you bench tested the pump to make sure it was not DOA? the V51 and F95 does tie into the fan module. The pump will not turn on unless the coolant sensor at the back of the engine reaches the desired temp. 103c for factory if I recall? Did you replace the coolant sensor with the lower temp on? 96c I think?

Lots of info here, start at page 10 (do read whole thing, lots of good info): SSP198 https://www.amb.org/ti/audi/2.7Biturbo-SelfStudy.pdf

speedyto

Yes, I have the new lower temp sensor and new after run Bosch pump. I did more troubleshooting over the weekend, powering the pump directly from the battery, turns ON but I don’t see any coolant moving in the reservoir also I add a in-line LED to confirm power at the pump after I put everything together. Now after driving the car and shut the engine off the after run fans are ON and the LED is ON confirming that the pump gets power (kind of hard to here the pump with the fans ON) still no coolant moving in the reservoir....I am wondering that I am really that lucky to get a new defective pump ? (far as I remember on my last 2002 Allroad when the after run pump was ON I could see the coolant on the return line in the reservoir). Next step I think will be to remove the line from the reservoir when the pump is ON and if I get nothing probably I will go with new OEM after run pump with relocating kit....or if anybody has any other suggestions I am ready to try 😊....thanks you

cu52

Look at page 10 of the link above as it shows the coolant routing. I have never seen the coolant moving in the expansion tank when mine were on. Also grab a mechanics stethescope from harborfreight: https://www.harborfreight.com/mechan...ope-63691.html put it to the pump through the intake manifold gaps to hear it. They are really quiet when on if brand new! You are probably all set.

speedyto

I will do that today, so if I don’t see coolant moving in the reservoir I shouldn’t worry longest the pump is running and the coolant moving it’s all good ?
Thank you for that manual very useful, I appreciate your help....I will post the results 😊

Confirmation LED for after run pump

speedyto

Using the mechanics stethoscope can confirm that the pump is running and also lots of noise from in/out hoses confirming the coolant flow. Far is the after run pump circuit after reading the the manual (page 10) looks like the after run pump is reversing the cooling circuit....so all good
Thanks' a lot for the help and provided docs, very helpful and valuable manual...cold not find anything in the big repair manual.

speedyto

After run pump circuit

cu52

Glad your all set. I like the after run pump, most of the b5 guys are just deleting them, but I found they worked well at controlling heat soak. Glad you kept it!

speedyto

Yes, I am glad I got to the bottom of it with your help. I never thought to deleted, I was ready to build my own timer 😊Audi spent lots of $$$ in development for a reason they have the pump there, bypassing the pump is the easy way always....cuts significantly the life of the turbos and other components.


Thank you