Fuel starvation, towed home by AA, help needed

StewartIngram · 23rd October 2020, 11:48

https://www.the75andztclub.co.uk/for...=302872&page=2

The last post on the above thread sums up the previous poor starting which plagued me for about 8 months, and seemed to have been cured. It might however bear some clues as to a new problem from yesterday!
Car is a 2.5 KV6 petrol auto, in good nick, about 113k miles. It is converted to lpg (by me, not the factory) and normally I only use petrol to start and for about 1/4 mile, when it changes to gas. However last weekend, I did my normal 15 mile trip to St.Ives and called in at Morrisons to fill up the lpg, only to find their pump locked. My next pump is 15 miles in the other direction from home, and yesterday I was on my way there when the problem happened. Earlier in the week the gas actually ran out, so I was running on petrol. All had been fine, but suddenly the engine hesitated then died. I managed to start it a couple of times, but it wouldn't rev, so the AA were called. Whilst waiting I did a few checks. At the Schrader valve at the front, there was some fuel, but not much pressure. When the ignition was turned on, the petrol pump ran for about 5 seconds as normal however. No obvious leaks were visible or could be smelt. Fuel gauge registered between 1/2 & 1/4 full, which seemed right to me by when I had last put some in, a couple of months previously, and by the mileage done on petrol. When the AA man came, his first thought was fuel filter splitting (the orange clip fault, though he wasn't aware of the clip being available as a mod). He was enthusiastic about finding the fault though, and when he left me (at home, after finally towing me there) he was disappointed at not knowing the result.
He thoroughly checked the filter and pump and tank area. He did find a tube not connected, which appeared that it should be going to to a clip on the fuel pump, but thought that it would make no difference being loose (nor did I). He also said that the rhs of the tank was pretty dry, which hinted at something amiss with the balance plumbing in the tank?
At home, I clipped that pipe on to the pump. It then started (but the fuel had sloshed around on the journey) but still wouldn't run. I went to the filter side and took that out. From the previous thread it will be noted that there was no paper cartridge in the filter, so I now took the chance to fit one. The other thing that I found, on the filter, was a black hose that looked as if it had been bent next to the fitting and was therefore crushed. (Possibly me when I took the filter out before?). To repair this I had to cut the end off and refit it. Also, the black wire to a tag on filter was broken and the tag had to be resoldered.
After putting it together again, it stiil won't start; fuel pump runs for 5 secs, but little pressure at the schrader valve. However there is pressure at the top pipe connector on the filter.
I'm not certain of a few things. Firstly, both the pump and filter are tight to get in, with the floats and pipes etc, have I trapped something? I can find no pictures to help. Rave has no description of the parts or operation. Secondly, Rimmers picture shows an expansion tank, and breather pipes. Again I can find no clear pics or descriptions. I have used the old test of removing the filler cap to check breathing to no avail. Thirdly, I wonder if the previous long use without a filter has resulted in a blockage somewhere. Is there a way of tracing through, possibly blowing through with an airline.
Next thing is, just to be sure, I going to get a can of petrol from the local garage and tip it into the rhs, just to make sure.

Stewart

planenut · 23rd October 2020, 12:32

Going back to basics, I would try the lighted taper test at the cylinders. Everybody will have their own solution for this one, good luck.

StewartIngram · 23rd October 2020, 13:06

OK, I just got 5L of petrol and put it in the rhs of the tank. Fired 1st time and runs ok. So the balance between tanks didn't work? Trikey's diagram shows a couple of static pumps involved. Now I don't know what they are, certainly not electric like the fuel pump. I wonder if they work under fuel pressure, if the fuel pump is actually working (as it now is). Will the fuel now balance? Or am I missing something.
I'm thing if I now drive to the garage and fill the tank, I will have (at least) the rhs fuel for the moment; a good mileage left. If I then go to the lpg pump and fill up, I will use that, thus preserving my stock of petrol until I can be certain the fault on petrol is clear. At a push I theoretically even start the car on lpg - though I've never tried.

T-Cut · 23rd October 2020, 13:20

I'd say you're still suffering from Fuel Filter Syndrome (FFS). The empty nearside of the tank indicates that the fuel level balancing system hasn't been working, probably due to the disconnected pipe. However, whether that was the culprit I can't guess. You'll soon know when you top up the tank with a few litres. You mentioned that there's 'pressure' at the filter outlet. I assume you couldn't measure it so the 'pressure' was a visual observation (?). The ECU won't issue a spark command unless the pressure at the rail is above a minimum around 50psi. A slight leak from the filter cap seal will reduce the pumped pressure enough to prevent startup. That seems to be a logical explanation. Having reviewed your earlier discussions, you haven't confirmed that the filter cap to body O-ring has been renewed. Did the filter element not come with this? If so, could it have been mis-fitted? I know from experience that this seal can be very fiddly to get right. The detached wire to the connector on the bottom of the filter module is part of the earthed safety circuit. It eliminates static sparking due to fluid flow.

If you want a little more insight on how the tank works, this might help https://www.the75andztclub.co.uk/for...d.php?t=108535

TC
EDIT: Oh, I see you've just proved my point about adding some juice. If driving returns to normal now, then the filter syndrome will be fixed with a new O-ring and the amber (white??) clip in place.

trikey · 23rd October 2020, 14:18

As TC says, try the O ring and a sealed filter 👍

StewartIngram · 23rd October 2020, 15:36

Just to add to the above. When I added 5L to the rhs, she started normally & ran ok, left it for over 15mins running, and revving ok. So I'm confident it was because it was low fuel level on the rhs. I confirm that when I eventually fitted the filter cartridge, I used 3 new o-rings, and also the clip. So no leak there now. Since then I've taken it to the garage and added £40 of fuel (ouch! I'm used to about £22 for a full fill lol) so if the fault is still there, I do have a good 3 months use left in which I can delve further. Worrying thing is that the fuel gauge didn't rise from its 1/4 tank setting at all with the £40. Maybe I've trapped one of the senders or something. What are the "static pumps"? I think I understand their purpose in the balancing etc, but how do they work? Do they need the presence of fuel moving round to make them work, something I didn't have before?

StewartIngram · 23rd October 2020, 15:37

edit to add - I also checked the small plastic filter, on an extension pipe from the big filter, was clean.

StewartIngram · 23rd October 2020, 15:56

Having read the "How-to Understand", I think I follow it better. And an apology, due to finding the diagram via another thread, I thought it was from Trikey, not T-Cut. Sorry to both of you.

T-Cut · 23rd October 2020, 17:58

Quote:

Originally Posted by StewartIngram

Worrying thing is that the fuel gauge didn't rise from its 1/4 tank setting at all with the £40. Maybe I've trapped one of the senders or something.

The filter (and pump) units have a downward facing 'lug' that engages with a cut-away in the tank port ring. This gives the correct positioning for the float arms. I doubt it's possible to refit the module without placing the lug correctly, but I'm not abolutely certain it can't be done. Of course any slight kink or bend put into the float arm itself can cause float obstruction. Another common cause is wear and tear on the rheostat windings which can cause resistance readings to be out. The ECU uses the combined rheostat readings to cumpute the gauge position. If you suspect a dodgy rheostat, check the resistances with an ohm meter.

There's also a HowTo fix this problem somewhere here (but the images have been lost).

Quote:

What are the "static pumps"?

Google 'venturi' and 'venturi pump' it should become obvious.

Quote:

I think I understand their purpose in the balancing etc, but how do they work? Do they need the presence of fuel moving round to make them work, something I didn't have before?

Yes, fuel must flow through them pretty quickly. The 75/ZT have always had them. EDIT: Oh, do you mean before you reconnected the black pipe? Then yes, I believe the black pipe operates one of the venturi pumps.

TC

StewartIngram · 23rd October 2020, 18:58

I'm understanding things a bit better now. Big problem is that everything is out of sight, in the tanks, and difficult to re-assemble. I agree that the pump and filter locate in one position only, but to get there you have to wiggle your way down though a collection of pipes and floats which always seem to hit obstructions. I'm thinking that next, I get my lpg filled up and then as normal run on that, using petrol for only the 1st 1/4 mile. That buys me a lot of time to fix things. After that, if I have the ignition switched on so the petrol gauge works, I should be able to check each sender, by manually moving it with the sender out of the tank? That should indicate which one is the problem surely? I'm thinking the pump one is the suspect, as with low fuel that side, most being on the lhs, it was showing approx 1/4 tank. Adding 5L didn't show any/much difference (tbh I didn't really notice though it looked more full). £40 then added should take it well up, probably 3/4 or so I would think. My guess is I have got no freedom of movement on a float when in the tank, and the last bit of pushing down the pump & filter seemed hard.

23rd October 2020, 11:48	#1
StewartIngram Gets stuck in Rover 75 Connoisseur 2.5 V6 auto Join Date: Jan 2008 Location: Chatteris, Cambridgeshire Posts: 902 Thanks: 320 Thanked 159 Times in 127 Posts	Fuel starvation, towed home by AA, help needed https://www.the75andztclub.co.uk/for...=302872&page=2 The last post on the above thread sums up the previous poor starting which plagued me for about 8 months, and seemed to have been cured. It might however bear some clues as to a new problem from yesterday! Car is a 2.5 KV6 petrol auto, in good nick, about 113k miles. It is converted to lpg (by me, not the factory) and normally I only use petrol to start and for about 1/4 mile, when it changes to gas. However last weekend, I did my normal 15 mile trip to St.Ives and called in at Morrisons to fill up the lpg, only to find their pump locked. My next pump is 15 miles in the other direction from home, and yesterday I was on my way there when the problem happened. Earlier in the week the gas actually ran out, so I was running on petrol. All had been fine, but suddenly the engine hesitated then died. I managed to start it a couple of times, but it wouldn't rev, so the AA were called. Whilst waiting I did a few checks. At the Schrader valve at the front, there was some fuel, but not much pressure. When the ignition was turned on, the petrol pump ran for about 5 seconds as normal however. No obvious leaks were visible or could be smelt. Fuel gauge registered between 1/2 & 1/4 full, which seemed right to me by when I had last put some in, a couple of months previously, and by the mileage done on petrol. When the AA man came, his first thought was fuel filter splitting (the orange clip fault, though he wasn't aware of the clip being available as a mod). He was enthusiastic about finding the fault though, and when he left me (at home, after finally towing me there) he was disappointed at not knowing the result. He thoroughly checked the filter and pump and tank area. He did find a tube not connected, which appeared that it should be going to to a clip on the fuel pump, but thought that it would make no difference being loose (nor did I). He also said that the rhs of the tank was pretty dry, which hinted at something amiss with the balance plumbing in the tank? At home, I clipped that pipe on to the pump. It then started (but the fuel had sloshed around on the journey) but still wouldn't run. I went to the filter side and took that out. From the previous thread it will be noted that there was no paper cartridge in the filter, so I now took the chance to fit one. The other thing that I found, on the filter, was a black hose that looked as if it had been bent next to the fitting and was therefore crushed. (Possibly me when I took the filter out before?). To repair this I had to cut the end off and refit it. Also, the black wire to a tag on filter was broken and the tag had to be resoldered. After putting it together again, it stiil won't start; fuel pump runs for 5 secs, but little pressure at the schrader valve. However there is pressure at the top pipe connector on the filter. I'm not certain of a few things. Firstly, both the pump and filter are tight to get in, with the floats and pipes etc, have I trapped something? I can find no pictures to help. Rave has no description of the parts or operation. Secondly, Rimmers picture shows an expansion tank, and breather pipes. Again I can find no clear pics or descriptions. I have used the old test of removing the filler cap to check breathing to no avail. Thirdly, I wonder if the previous long use without a filter has resulted in a blockage somewhere. Is there a way of tracing through, possibly blowing through with an airline. Next thing is, just to be sure, I going to get a can of petrol from the local garage and tip it into the rhs, just to make sure. Stewart

23rd October 2020, 13:20	#4
T-Cut This is my second home Rover75 and Mreg Corsa. Join Date: Nov 2006 Location: Sumweer onat mote o'dust (Sagin) Posts: 21,753 Thanks: 341 Thanked 3,660 Times in 2,924 Posts	I'd say you're still suffering from Fuel Filter Syndrome (FFS). The empty nearside of the tank indicates that the fuel level balancing system hasn't been working, probably due to the disconnected pipe. However, whether that was the culprit I can't guess. You'll soon know when you top up the tank with a few litres. You mentioned that there's 'pressure' at the filter outlet. I assume you couldn't measure it so the 'pressure' was a visual observation (?). The ECU won't issue a spark command unless the pressure at the rail is above a minimum around 50psi. A slight leak from the filter cap seal will reduce the pumped pressure enough to prevent startup. That seems to be a logical explanation. Having reviewed your earlier discussions, you haven't confirmed that the filter cap to body O-ring has been renewed. Did the filter element not come with this? If so, could it have been mis-fitted? I know from experience that this seal can be very fiddly to get right. The detached wire to the connector on the bottom of the filter module is part of the earthed safety circuit. It eliminates static sparking due to fluid flow. If you want a little more insight on how the tank works, this might help https://www.the75andztclub.co.uk/for...d.php?t=108535 TC EDIT: Oh, I see you've just proved my point about adding some juice. If driving returns to normal now, then the filter syndrome will be fixed with a new O-ring and the amber (white??) clip in place. Last edited by T-Cut; 23rd October 2020 at 13:28..

23rd October 2020, 14:18	#5
trikey Premium Trader Rover 75 Join Date: Nov 2010 Location: Devon Posts: 33,768 Thanks: 8,837 Thanked 14,831 Times in 8,030 Posts	As TC says, try the O ring and a sealed filter 👍 __________________ Lest we forget..

23rd October 2020, 12:32	#2
planenut Regional Secretary Rover 1.8T Tourer Join Date: May 2007 Location: Heathrow Posts: 6,955 Thanks: 1,551 Thanked 2,036 Times in 1,264 Posts	Going back to basics, I would try the lighted taper test at the cylinders. Everybody will have their own solution for this one, good luck.

23rd October 2020, 13:06	#3
StewartIngram Gets stuck in Rover 75 Connoisseur 2.5 V6 auto Join Date: Jan 2008 Location: Chatteris, Cambridgeshire Posts: 902 Thanks: 320 Thanked 159 Times in 127 Posts	OK, I just got 5L of petrol and put it in the rhs of the tank. Fired 1st time and runs ok. So the balance between tanks didn't work? Trikey's diagram shows a couple of static pumps involved. Now I don't know what they are, certainly not electric like the fuel pump. I wonder if they work under fuel pressure, if the fuel pump is actually working (as it now is). Will the fuel now balance? Or am I missing something. I'm thing if I now drive to the garage and fill the tank, I will have (at least) the rhs fuel for the moment; a good mileage left. If I then go to the lpg pump and fill up, I will use that, thus preserving my stock of petrol until I can be certain the fault on petrol is clear. At a push I theoretically even start the car on lpg - though I've never tried.

23rd October 2020, 15:36	#6
StewartIngram Gets stuck in Rover 75 Connoisseur 2.5 V6 auto Join Date: Jan 2008 Location: Chatteris, Cambridgeshire Posts: 902 Thanks: 320 Thanked 159 Times in 127 Posts	Just to add to the above. When I added 5L to the rhs, she started normally & ran ok, left it for over 15mins running, and revving ok. So I'm confident it was because it was low fuel level on the rhs. I confirm that when I eventually fitted the filter cartridge, I used 3 new o-rings, and also the clip. So no leak there now. Since then I've taken it to the garage and added £40 of fuel (ouch! I'm used to about £22 for a full fill lol) so if the fault is still there, I do have a good 3 months use left in which I can delve further. Worrying thing is that the fuel gauge didn't rise from its 1/4 tank setting at all with the £40. Maybe I've trapped one of the senders or something. What are the "static pumps"? I think I understand their purpose in the balancing etc, but how do they work? Do they need the presence of fuel moving round to make them work, something I didn't have before?

23rd October 2020, 15:37	#7
StewartIngram Gets stuck in Rover 75 Connoisseur 2.5 V6 auto Join Date: Jan 2008 Location: Chatteris, Cambridgeshire Posts: 902 Thanks: 320 Thanked 159 Times in 127 Posts	edit to add - I also checked the small plastic filter, on an extension pipe from the big filter, was clean.

23rd October 2020, 15:56	#8
StewartIngram Gets stuck in Rover 75 Connoisseur 2.5 V6 auto Join Date: Jan 2008 Location: Chatteris, Cambridgeshire Posts: 902 Thanks: 320 Thanked 159 Times in 127 Posts	Having read the "How-to Understand", I think I follow it better. And an apology, due to finding the diagram via another thread, I thought it was from Trikey, not T-Cut. Sorry to both of you.

23rd October 2020, 18:58	#10
StewartIngram Gets stuck in Rover 75 Connoisseur 2.5 V6 auto Join Date: Jan 2008 Location: Chatteris, Cambridgeshire Posts: 902 Thanks: 320 Thanked 159 Times in 127 Posts	I'm understanding things a bit better now. Big problem is that everything is out of sight, in the tanks, and difficult to re-assemble. I agree that the pump and filter locate in one position only, but to get there you have to wiggle your way down though a collection of pipes and floats which always seem to hit obstructions. I'm thinking that next, I get my lpg filled up and then as normal run on that, using petrol for only the 1st 1/4 mile. That buys me a lot of time to fix things. After that, if I have the ignition switched on so the petrol gauge works, I should be able to check each sender, by manually moving it with the sender out of the tank? That should indicate which one is the problem surely? I'm thinking the pump one is the suspect, as with low fuel that side, most being on the lhs, it was showing approx 1/4 tank. Adding 5L didn't show any/much difference (tbh I didn't really notice though it looked more full). £40 then added should take it well up, probably 3/4 or so I would think. My guess is I have got no freedom of movement on a float when in the tank, and the last bit of pushing down the pump & filter seemed hard.