in tank pump

[Mike Noc]

Originally Posted by HarryM1BYT

Complex it certainly is, but I don't think the system fails as frequently as you suggest. You only get the failures reported in a forum, never the pumps which just keep plodding along for years as mine has done.

Yes there isn't anything wrong with the system itself, they just got the ITP commutator/commutator brush set up wrong.

Either the brushes are too hard or the commutator material too soft as the brushes don't wear but the commutator itself does.

[3disco]

Originally Posted by Mike Noc

You aren't getting the fuel burning heater supply hose mixed up with the outlet pipe to the UBP?

The return pipe and fuel burning heater supply pipe are both situated in the offside tank module top and the outlet pipe to the UBP is on the nearside module top.

If you unplug the UBP then disconnect the outlet pipe on the nearside tank module and stick a smaller pipe in the connection and the other end in a jar, with key to position 2 you should get fuel flowing out if the ITP is working.

All is explained,thanks Mike ,I wrongly assumed the outlet pipe was on the o/s and not the n/s.

[HarryM1BYT]

Originally Posted by bobthethird

Out of general interest has anyone had a UBP fail when the ITP is still working, or have people just changed the UBP without checking the other pump.
I am thinking more about garage repairs, it is easy to diagnose the UBP, change it, and just ignore the other one. This of course is just storing up trouble for the future, and giving out cries of "That new pump didn't last long."

A rough check that the ITP is running, is to simply turn the ignition on and listen at the fuel filler with the cap removed. The pump will run for a few seconds without the engine being started. The noise of the pump doesn't guarantee it is pumping, but it is a fair indication that all is well and only takes seconds to carry out as a regular task.

[jim lee]

Post from Mike Noc very interesting. The vent valve on the top of the ITP appears to be the 'cause' of the UBP not being able to draw fuel from the tank when less than quarter full. I do not know the details of the ITK but would it be possible to fit a pipe to the outlet of this vent vale and lead it to a low point in the tank where it would be immersed in fuel even when the tank is nearly empty? Such a pipe should allow the ITK pump to vent, while priming, but allow the UBP to draw fuel from the tank even if he level is below the top of the ITP and its vent valve.

I do not know if fitting such a connection is possible but the idea may be worth a try. Or am I missing something?

[bubs]

i think the problem would be the amount of crud you would end up sucking up along with the fuel

[HarryM1BYT]

Originally Posted by bubs

i think the problem would be the amount of crud you would end up sucking up along with the fuel

I doubt you would find any crud in a modern cars tank which uses injection. There is too much circulation of fuel and it all flows constantly through a filter which removes any crud.

[Mike Noc]

Originally Posted by jim lee

Post from Mike Noc very interesting. The vent valve on the top of the ITP appears to be the 'cause' of the UBP not being able to draw fuel from the tank when less than quarter full. I do not know the details of the ITK but would it be possible to fit a pipe to the outlet of this vent vale and lead it to a low point in the tank where it would be immersed in fuel even when the tank is nearly empty? Such a pipe should allow the ITK pump to vent, while priming, but allow the UBP to draw fuel from the tank even if he level is below the top of the ITP and its vent valve.

I do not know if fitting such a connection is possible but the idea may be worth a try. Or am I missing something?

Funnily enough I had to do a similar thing to my daughter's Freelander TD4 when the ITP failed.

Car wouldn't run even with plenty of fuel in the tank (the ITP module is a different design to ours) so ended up removing the outlet pipe from the ITP and cable tying it to the base of the module to keep the car on the road until the replacement arrived.

[vince75]

Originally Posted by 3disco

I have just replaced the intank fuel pump on my 75 cdti tourer as its not been working for several years and wondered that if the intank pump is just for transferring fuel from one side of the tank to the other and the underbonnet pump sucks fuel from the tank for delivery to the hp pump what feeds the hp pump when the underbonnet pump was deleted on the later models,what am I missing? thanks in advance.

Been following this thread with interest.Its been mentioned that later models did away with this underbonnet pump does anyone know when this change happened

[T-Cut]

Originally Posted by 3disco

Does nobody know the answer?

It may be in here somewhere:

Click: http://www.the75andztclub.co.uk/foru...d.php?t=108535

TC

[DMGRS]

I tend to sell many more under bonnet pumps than in tank pumps, by a ratio of about 3:1.