OBD2 Conversion just finished... Aux water pump staying on?

[P3rks 11]

Quick question..

 

I've just finished my OBD2 conversion and its running for the first time. Yippie!

 

The aux water pump seems to be staying on for a while after the engines been turned off. Even with the keys out. It'll go off if you remove one of the battery terminals. but as soon as you turn the ignition on again it comes back on and stays on. It did it from cold and warmed up. It does goes off after a while though (went in to clean up, checked the car and it was off). Is this normal? It didn't do it before.

 

Also, I can hear an intermittent electrical buzzing sound coming from the MAF area. It could be either the MAF, the charcoal valve or the ABS connection on the turret. I can't narrow it down. Any thoughts?

Edited April 20, 2013 by P3rks

[vw rule 19]

Hello there,

 

I believe the electric auxiliary water pump does stay on from time to time when the engine has been running for a wile,

as the VR6 engines do tend to run hot,

so there may be a engine bay air temp sensor which tells the pump to stay on, plus you should hear your cooling fan / fans cut in as well.

 

Not sure about your intermittent buzzing noise, I'd have to hear it to be sure.

 

Si

 

---------- Post added at 11:04 PM ---------- Previous post was at 10:53 PM ----------

 

The only other thing is, you haven't got anything unplugged or a earth off somewhere,

as this can some times course a buzzing noise from a control unit or sensor.

 

Remember that when you disconnect your battery you remove the earth terminal first, and then connect it back second after the positive lead,

other wise you could blow something.

 

Si :thumbleft:

[P3rks 11]

Thanks for the input. I have found a few posts saying the aux pump should stay on for 10 minutes, but can't really find anything to confirm that. The concern was that it stayed on from cold. The fans kick in as they should and at variable speeds; so all is good there. It's just the aux water pump which concerns me.

 

I believe I have everything plugged in correctly, the earths are fastened down. The difference with the earths from OBD1 to OBD2 is that on the OBD1 the four earths are on the engine harness block which fastens to the inlet/head. The OBD2 however has two earths on that inlet/head block and two which I placed on the chassis earth point next to the battery. They were cleaned but admittably I could have sanded the joining surfaces better. I'll try that first.

 

I'll get the car on VAGCOM this morning to look for faults.

 

I wonder is that buzzing could be the throttle body aligning? Having a stepper motor and all...

Edited April 21, 2013 by P3rks

[VR6Pete 0]

Think the aux pump runs from yellow temp sensor. Unplug the sensor, does it still run then?

[P3rks 11]

The yellow temp makes no difference.

 

It's associated with the small plug on the fan control module. Strangely enough when the aux pumps has kicked in, if you unplug the small connection on the control module the pump switches off, but plug the connection it back in and the pump comes back on. There has to be a timed relay in the control module. It does this with the ignition off too!

 

Also, the aux pump turns itself off within 10 minutes (I timed it). It's just a concern it automatically comes on with ignition.

 

 

Regarding the buzzing sound, I believe it's the throttle body adapting and moving - the sounds just resonating through the intake pipes. I believe.

[VR6Pete 0]

The yellow temp makes no difference.

 

It's associated with the small plug on the fan control module. Strangely enough when the aux pumps has kicked in, if you unplug the small connection on the control module the pump switches off, but plug the connection it back in and the pump comes back on. There has to be a timed relay in the control module. It does this with the ignition off too!

 

Also, the aux pump turns itself off within 10 minutes (I timed it). It's just a concern it automatically comes on with ignition.

 

 

Regarding the buzzing sound, I believe it's the throttle body adapting and moving - the sounds just resonating through the intake pipes. I believe.

 

If the yellow sensor is unplugged, I wouldn't have expected aux pump to run after ignition is off.

 

The small plug on the FCM is for the aux pump so unplugging it and it stopping is expected behaviour.

 

Can't remember if mine runs on ignition or not. Can't honestly remember, but it running is better than it not running...

 

With regards to the buzzing, my throttle body also does the same.