MG ZT Diesel Fuel pressure issue - Page 3

mostin6556 · 5th May 2015, 20:39

Okay I'm struggling to find any in g o on the plastic bit with the hook that's in my picture should be attached to. Any ideas or a name of it to search. Clearly it has a hook for a reason and shouldn't just be lobbed in the tank.

Avulon · 5th May 2015, 20:40

Quote:

Originally Posted by mostin6556

see now I thought that and i could clearly see i wasn't the first person to remove the pump. But i couldn't see how to hook it or where.

its this bit

Take a read of paragraph 3 here : http://www.the75andztclub.co.uk/foru...ead.php?t=4512

(I found the 'how to'

)

PS:: Just read on to step 7 which describes how to fit it back into the tank.

mostin6556 · 5th May 2015, 20:47

Thank you very much. Here is a virtual beer 🍻

I will have a rummage in the tank. Not liking the the "remember where it came from as it's a pain to go back in" as it's already just splashing about (it was like that when I got here) part 7 does give a bit of info like you say so shall give it a whirl.

I will report back my findings findings.

Avulon · 5th May 2015, 20:52

Quote:

Originally Posted by mostin6556

Thank you very much. Here is a virtual beer 🍻

I will have a rummage in the tank. Not liking the the "remember where it came from as it's a pain to go back in" as it's already just splashing about (it was like that when I got here)

I will report back my findings findings.

Keeping my fingers crossed for you, I'll have the beer when you've managed to get it in place. Hope it helps things when it is in correctly.

mostin6556 · 8th May 2015, 19:54

Just a quick update

Having been back in the tank i struggled to get this arm back in place so removed pipe from the new pump to make life easier. (broke new pump connection off) managed to get the arm thing in place and have a good look at pipe work and from what i can see and correct me if i'm wrong the only function of the intank pump is to is to pull fuel from the other side to be picked up by the UBP. So as long as there's fuel in the this half the in tank pump is un required and therefore not the cause of the problem. Think it is either LP sensor (replacement filter housing and sensor will be here tomorrow) or a blocked pipe. will update progress over weekend.

Avulon · 9th May 2015, 00:18

Well done on getting it in place - having not removed it yourself in the first place.

On the subject of the intank pump-it lifts the fuel providing a low pressure supply to the UBP. With enough fuel in the tank the 'head' of fuel is enough to supply the UBP on it's own (but does still stress the UBP as it's under more strain now). You should note that it was the ITP that was uprated and the UBP deleted on the later models (if I've read previous posts on the subject correctly) - not the other way around. You can test the low pressure sensor by disconnecting it - if faulty then symptoms should improve, there's also a simple voltage test for the sensor itself - can't remember the values right now but should be easily findable (use the google search). I haven't heard of a blocked pipe yet - but there's always a first time!

Good luck ...

Mike Noc · 9th May 2015, 06:39

The reason the engine stops with a defective ITP and less than a quarter of a tank of fuel onboard is that the UBP ends up sucking air not fuel.

The ITP has two ball valves at the top: a spring loaded normally closed pressure relief valve, and a normally open priming valve, which closes as the ITP primes and pressurises.

When the level drops in the tank it eventually reaches the top of the ITP, and the UBP starts sucking air in through the open priming valve.

With a failed ITP the UBP does have a bit more work to do, but it doesn't over stress it. I have run a UBP on its own for over 20k miles with no problems and other owners have done the same for far longer.

Unfortunately, like the ITPs, the UBP will eventually wear out, although they usually last a fair bit longer. And when they do the ITP is often found to have already failed, so maybe that is where the assumption is made that the failing ITP stressed the UBP?

The ITP isn't just used to help keep the tank levels equal either side. The Freelander TD4, which uses the M47R engine, has a flat bottomed tank, but still has an ITP.

.

mostin6556 · 9th May 2015, 10:30

Quote:

Originally Posted by Mike Noc

The reason the engine stops with a defective ITP and less than a quarter of a tank of fuel onboard is that the UBP ends up sucking air not fuel.

The ITP has two ball valves at the top: a spring loaded normally closed pressure relief valve, and a normally open priming valve, which closes as the ITP primes and pressurises.

When the level drops in the tank it eventually reaches the top of the ITP, and the UBP starts sucking air in through the open priming valve.

With a failed ITP the UBP does have a bit more work to do, but it doesn't over stress it. I have run a UBP on its own for over 20k miles with no problems and other owners have done the same for far longer.

Unfortunately, like the ITPs, the UBP will eventually wear out, although they usually last a fair bit longer. And when they do the ITP is often found to have already failed, so maybe that is where the assumption is made that the failing ITP stressed the UBP?

The ITP isn't just used to help keep the tank levels equal either side. The Freelander TD4, which uses the M47R engine, has a flat bottomed tank, but still has an ITP.

.

Okay I don't see how the Intank pump has any involvement with the UBP. The feed to the UBP is connects onto a pipe that runs down the side of the intank pump and picks up fuel from below. My intank pump is not directly connected to the feed to the engine. The second pipe that connects seems to just be a think black pipe inside that feeds back into the tank its self which is the return. As such how can the intank pump make any difference apart from the 1/4 tank issues as one side has fuel and not the other.

the arrows point to the pipe that attaches to the top. the second thin black pipe just fits in through the tube so neither are connected to the intank pump so how does it help the UBP

mostin6556 · 9th May 2015, 10:42

Quote:

Originally Posted by Avulon

Well done on getting it in place - having not removed it yourself in the first place.

On the subject of the intank pump-it lifts the fuel providing a low pressure supply to the UBP. With enough fuel in the tank the 'head' of fuel is enough to supply the UBP on it's own (but does still stress the UBP as it's under more strain now). You should note that it was the ITP that was uprated and the UBP deleted on the later models (if I've read previous posts on the subject correctly) - not the other way around. You can test the low pressure sensor by disconnecting it - if faulty then symptoms should improve, there's also a simple voltage test for the sensor itself - can't remember the values right now but should be easily findable (use the google search). I haven't heard of a blocked pipe yet - but there's always a first time!

Good luck ...

Thanks It was a pig to get in especially as not got a clue where it went but after splashing round in a load of diesel and breaking my nice new intank pump it went in. I have unplugged the LP sesnor and car runs fine(ish maybe a little slow on the take off but i think that might just be how it runs as not exactly over run with horsepower.......yet). if my new switch and housing turn up today will fit and see how i get on whilst putting old in tank pump back in so i can go Manchester and back at 3 in the morning.

Mike Noc · 9th May 2015, 11:09

Quote:

Originally Posted by mostin6556

Okay I don't see how the Intank pump has any involvement with the UBP. The feed to the UBP is connects onto a pipe that runs down the side of the intank pump and picks up fuel from below. My intank pump is not directly connected to the feed to the engine. The second pipe that connects seems to just be a think black pipe inside that feeds back into the tank its self which is the return. As such how can the intank pump make any difference apart from the 1/4 tank issues as one side has fuel and not the other.

the arrows point to the pipe that attaches to the top. the second thin black pipe just fits in through the tube so neither are connected to the intank pump so how does it help the UBP

Looks like we might be getting to the bottom of the problem.

It should be plumbed in like this: The feed to the UBP is taken from the top of the tank module on near side of the car. The spill return is connected to the top of the tank module on the offside of the car, along with the thin pipe which is the separate feed to the fuel burning heater.

I've traced some of the pipework out, but not the interconnections within the tank. Look at #Post 4 here to see the diagram of the internal tank pipework.

http://www.the75andztclub.co.uk/foru...d.php?t=172055

There have been discussions about how accurate it is but I think if yours differs from the diagram then it could be that, in the past someone has dabbled with it.

It certainly wouldn't be the first time an owner has come across bodged up tank plumbing.

5th May 2015, 20:47	#23
mostin6556 Newbie MG ZT-T Join Date: Mar 2013 Location: Stafford Posts: 19 Thanks: 0 Thanked 0 Times in 0 Posts	Thank you very much. Here is a virtual beer 🍻 I will have a rummage in the tank. Not liking the the "remember where it came from as it's a pain to go back in" as it's already just splashing about (it was like that when I got here) part 7 does give a bit of info like you say so shall give it a whirl. I will report back my findings findings. Last edited by mostin6556; 5th May 2015 at 20:53..

9th May 2015, 00:18	#26
Avulon This is my second home 1.8t Tourer Join Date: Oct 2011 Location: Tanelorn Posts: 4,830 Thanks: 956 Thanked 1,148 Times in 916 Posts	Well done on getting it in place - having not removed it yourself in the first place. On the subject of the intank pump-it lifts the fuel providing a low pressure supply to the UBP. With enough fuel in the tank the 'head' of fuel is enough to supply the UBP on it's own (but does still stress the UBP as it's under more strain now). You should note that it was the ITP that was uprated and the UBP deleted on the later models (if I've read previous posts on the subject correctly) - not the other way around. You can test the low pressure sensor by disconnecting it - if faulty then symptoms should improve, there's also a simple voltage test for the sensor itself - can't remember the values right now but should be easily findable (use the google search). I haven't heard of a blocked pipe yet - but there's always a first time! Good luck ... __________________ Need a T4 ?: T4 Owners Map thanks to Stevestrat ( use at your own risk) Where?: https://en.wikipedia.org/wiki/Tanelorn Mods/Retrofits: PCV vortex 'filter'; bluetooth; inline thermostat; reversing sensors; plenum spyhole ; headlamp washers ; Diy mp3 player replacing CD multichanger; FBH with remote; Headlamp washers; black/chrome front grille, rear blind; Xenon projectors To do: puddle lights; 2 Din cd/nav to fit; boot release button

9th May 2015, 06:39	#27
Mike Noc This is my second home Rover 75 CDT Manual Connoisseur SE, Rover 75 CDT Automatic Connoisseur SE & a Freelander Td4. Join Date: Jul 2009 Location: Hampshire Posts: 11,571 Thanks: 3,470 Thanked 3,119 Times in 2,247 Posts	The reason the engine stops with a defective ITP and less than a quarter of a tank of fuel onboard is that the UBP ends up sucking air not fuel. The ITP has two ball valves at the top: a spring loaded normally closed pressure relief valve, and a normally open priming valve, which closes as the ITP primes and pressurises. When the level drops in the tank it eventually reaches the top of the ITP, and the UBP starts sucking air in through the open priming valve. With a failed ITP the UBP does have a bit more work to do, but it doesn't over stress it. I have run a UBP on its own for over 20k miles with no problems and other owners have done the same for far longer. Unfortunately, like the ITPs, the UBP will eventually wear out, although they usually last a fair bit longer. And when they do the ITP is often found to have already failed, so maybe that is where the assumption is made that the failing ITP stressed the UBP? The ITP isn't just used to help keep the tank levels equal either side. The Freelander TD4, which uses the M47R engine, has a flat bottomed tank, but still has an ITP. . Last edited by Mike Noc; 9th May 2015 at 08:10..

5th May 2015, 20:39	#21
mostin6556 Newbie MG ZT-T Join Date: Mar 2013 Location: Stafford Posts: 19 Thanks: 0 Thanked 0 Times in 0 Posts	Okay I'm struggling to find any in g o on the plastic bit with the hook that's in my picture should be attached to. Any ideas or a name of it to search. Clearly it has a hook for a reason and shouldn't just be lobbed in the tank.

8th May 2015, 19:54	#25
mostin6556 Newbie MG ZT-T Join Date: Mar 2013 Location: Stafford Posts: 19 Thanks: 0 Thanked 0 Times in 0 Posts	Just a quick update Having been back in the tank i struggled to get this arm back in place so removed pipe from the new pump to make life easier. (broke new pump connection off) managed to get the arm thing in place and have a good look at pipe work and from what i can see and correct me if i'm wrong the only function of the intank pump is to is to pull fuel from the other side to be picked up by the UBP. So as long as there's fuel in the this half the in tank pump is un required and therefore not the cause of the problem. Think it is either LP sensor (replacement filter housing and sensor will be here tomorrow) or a blocked pipe. will update progress over weekend.