Club 80-90 Forums

Can anybody explain how to test the fuel pump 24v... have 22v going to it ...
On 200 on the ohms I get 33 but have no idea what that means ?? Thanks in advance

Depends upon which Airtop model, Airtop32/24 or Airtop 2000/3500/5000/evo models.
2000 should be around 20Ω others may be 33Ω. 33Ω can be used to slow down the pump rate slightly when 20Ω gives too high a heat output.
Pulse 24v across the terminals to test - only with the pump disconnected from the heater. What do you mean 'have 22v going to it'? There shouldn't be a constant voltage at the pump only a pulsed one sent by the ecu.

Thanks for your reply Mr Goddie, if I switch it on and put the meter across the connector I get the 22v.... if I put a24v supply to the pump it does nothing but spark as the connection is made ..... guess that shows the pump has quit ????

Are you pulsing the 24v supply? - you will get a spark as the contact is made as it draws current. 33Ω says that there isn't anything wrong to me.

Thanks .... do they stick if not often used ??

If you just apply 24v to the pump it will just click once and then again when you remove the supply
( make sure you have removed the heaters connection to the pump first )
It's a electromagnetic pulse pump , appply power , remove power , apply power , remove power to make it pump

I'm elevated to the godhead now!

Could be worse, suppose he spelt the first bit it incorrectly